学习SpringMVC
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学习视频： www.bilibili.com/video/BV1aE…
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Spring:IOC和AOP必须掌握
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SpringMVC:执行流程必须掌握
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官网： docs.spring.io/spring/docs…
1.1 什么是MVC？
- Model：数据模型，提供要展示的数据，因此包含数据和行为，可以认为是领域模型或JavaBean组件（包含数据和行为），不过现在一般都分离开来：Value Object（数据Dao） 和 服务层（行为Service）。也就是模型提供了模型数据查询和模型数据的状态更新等功能，包括数据和业务。
- View:负责进行模型的展示，一般就是我们见到的用户界面，客户想看到的东西。
- Controller（调度员）： 接收用户请求，委托给模型进行处理（状态改变），处理完毕后把返回的模型数据返回给视图，由视图负责展示。也就是说控制器做了个调度员的工作。
- 最常用的MVC：（Model）Bean +（view） Jsp +（Controller） Servlet
1.2 Model1时代
- 分为：视图层V和模型层M；由视图层的view来控制分发数据并展示给用户
- 缺点：JSP职责不单一，过重，不便于维护
1.3 Model2时代（MVC延续至今）
- 流程：分为了Contrller,Model,View
- 访问流程：
- 用户发请求
- Servlet接收请求数据，并调用对应的业务逻辑方法
- 业务处理完毕，返回更新后的数据给servlet
- servlet转向到JSP，由JSP来渲染页面
- 响应给前端更新后的页面
1.4 回顾Servlet创建
- 创建maven,父工程：pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.ssl</groupId>
<artifactId>SpringMVC</artifactId>
<packaging>pom</packaging>
<version>1.0-SNAPSHOT</version>
<!--父工程导入依赖-->
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.10.0</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.62</version>
</dependency>
</dependencies>
<!--资源过滤器，防止导入资源失败问题，最好在父子pom.xml里都加入一下代码-->
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
</build>
</project>
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- 创建子工程，idea右键Add Framwork Support添加web支持
- 实现HelloServlet继承HttpServlet接口，并创建/WEB-INF/jsp/test.jsp
public class HelloServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//1 获得参数
//2 调用业务层
//3 视图转发或者重定向
req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doPost(req, resp);
}
}
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- web.xml中注册HelloServlet,测试跳转： http://localhost:8080/springmvc_01_servlet//helloServlet
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>HelloServlet</servlet-name>
<servlet-class>com.ssl.web.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloServlet</servlet-name>
<url-pattern>/helloServlet</url-pattern>
</servlet-mapping>
</web-app>
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2 第一个SpringMVC
- 概念：SpringMVC是Spring框架中的一个分支，是基于Java实现MVC的轻量级Web框架
- 核心：Spring的web框架围绕 DispatcherServlet [ 调度Servlet ] 设计的。
2.1 执行原理
SpringMVC底层工作原理：
- DispatcherServlet表示前置控制器，是整个SpringMVC的控制中心。用户发出请求，DispatcherServlet接收请求并拦截请求。
- 假设url为 : http://localhost:8080/SpringMVC/hello
- 服务器域名： http://localhost:8080
- web站点：/SpringMVC
- hello表示控制器：/hello
- 通过分析，如上url表示为：请求位于服务器localhost:8080上的SpringMVC站点的hello控制器。
- HandlerMapping为处理器映射。DispatcherServlet调用HandlerMapping,HandlerMapping根据请求url查找Handler。
- HandlerExecution表示具体的Handler,其主要作用是根据url查找控制器，如上url被查找控制器为：hello。
- HandlerExecution将解析后的信息传递给DispatcherServlet,如解析控制器映射等。
- HandlerAdapter表示处理器适配器，其按照特定的规则去执行Handler。
- Handler让具体的Controller执行。
- Controller将具体的执行信息返回给HandlerAdapter,如ModelAndView。
- HandlerAdapter将视图逻辑名或模型传递给DispatcherServlet。
- DispatcherServlet调用视图解析器(ViewResolver)来解析HandlerAdapter传递的逻辑视图名。
- 视图解析器将解析的逻辑视图名传给DispatcherServlet。
- DispatcherServlet根据视图解析器解析的视图结果，调用具体的视图。
- 最终视图呈现给用户。
2.2 不使用注解开发
- 了解具体的执行过程=面试谈资。虽然开发中不会这么麻烦的使用，但必须看完-理解-继续学习
1 配置web.xml
- 完成DispatcherServlet，关联resource配置文件
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!--配置DispatcherServlet:SpringMVC核心-->
<servlet>
<servlet-name>SpringMvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--关联一个SpringMvc的resource配置文件-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springMvc_servlet.xml</param-value>
</init-param>
<!--启动级别-->
<load-on-startup>1</load-on-startup>
</servlet>
<!--匹配所有的请求： / :只匹配请求，不包含所有的.jsp
/*:匹配所有的请求，包括jsp页面
-->
<servlet-mapping>
<servlet-name>SpringMvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
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2 配置springMvc_servlet.xml
- 获得视图解析器、映射器、适配器，绑定跳转url
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:c="http://www.springframework.org/schema/c"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
https://www.springframework.org/schema/aop/spring-aop.xsd">
<!--处理器映射器HandlerMapping:查找访问的url控制器-->
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
<!--处理器适配器HandlerAdapter：controller将处理好的数据返回给HandlerAdapter-->
<bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
<!--视图解析器ViewResolver：将后端处理好的数据和视图传给DispatchServlet，DS再交给ViewResolver先解析一遍，确认无误再传给前端
必须熟悉，以后还要学模版引擎Thymeleaf/Freemarker...
1 获取ModeAndView的数据
2 解析ModeAndView的视图名字
3 拼接视图名字，找到对应的视图 WEB-INF/jsp/hello.jsp
-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
<!--BeanNameUrlHandlerMapping处理器：绑定跳转的url=页面访问的网址-->
<bean id="/hello" class="com.ssl.controller.HelloController"/>
</beans>
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3 /WEB-INF/jsp/hello.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>hello</title>
</head>
<body>
<%--接受传递的参数--%>
${msg}
</body>
</html>
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4 HelloController实现Controller
- 访问： http://localhost:8080/springmvc_02_hellomvc/hello
public class HelloController implements Controller {
@Override
public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
//1 创建modelAndView
ModelAndView mv = new ModelAndView();
//2 调用业务层，这里没有，就不写
//3 封装对象，放在mv中添加
mv.addObject("msg", "Hello SpringMvc");
//4 封装要跳转的视图，WEB-INF/jsp/hello.jsp
mv.setViewName("hello");
return mv;
}
}
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==5 SpringMVC原理回顾==
- 反复观看，理解原理！
2.3 使用注解开发
1 web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!--与前面一样-->
<servlet>
<servlet-name>springMvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springMvc_servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springMvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
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2 springMvc_servlet.xml
- 注解省略了映射器、适配器，专注于写视图解析器；跳转的Controller也不用配置进Spring
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--自动扫描包，让指定包下的注解生效，由IOC容器统一管理-->
<context:component-scan base-package="com.ssl.controller"/>
<!--让SpringMvc不处理静态资源。让.css,.js等不进视图解析器-->
<mvc:default-servlet-handler/>
<!--注解加载映射器、适配器，不用之前那么麻烦配置了-->
<mvc:annotation-driven/>
<!--配置视图解析器-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>
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3 /WEB-INF/jsp/hello.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>hello</title>
</head>
<body>
${msg}
</body>
</html>
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4 HelloController
- 简化了实现的接口，使用@注解配置映射器
- 访问： http://localhost:8080/springmvc_03_annotation/hello
@Controller
public class HelloController {
/**
* @param model 模型
* @return 被视图解析器处理：访问"/WEB-INF/jsp/hello.jsp资源
* 访问的url:RequestMapping("/hello")
*/
@RequestMapping("/hello")
public String hello(Model model) {
//封装数据
model.addAttribute("msg", "Hello SpringMvc_annotation");
//被视图解析器处理：访问"/WEB-INF/jsp/hello.jsp资源
return "hello";
}
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3 Controller和RestFul
- 配置web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>springMvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring_mvc_servlet.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>springMvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<!-- <filter>
<filter-name>encode</filter-name>
<filter-class>com.ssl.filter.EncodeFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>encode</filter-name>
<url-pattern>/</url-pattern>
</filter-mapping>-->
<filter>
<filter-name>encode</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encode</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
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- spring_mvc_servlet.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--自动扫描包，让指定包下的注解生效，由IOC容器统一管理-->
<context:component-scan base-package="com.ssl.controller"/>
<!--让SpringMvc不处理静态资源。让.css,.js等不进视图解析器-->
<mvc:default-servlet-handler/>
<!--注解加载映射器、适配器，不用之前那么麻烦配置了-->
<mvc:annotation-driven/>
<!--以上的是定死的代码，
以下是配置视图解析器-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
<!--不使用注解开发的适配器：/demo1,注意点是id需要配置/-->
<bean id="/demo" class="com.ssl.controller.ControllerDemo1"/>
</beans>
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3.1 Controller
- 不使用注解，极其不推荐使用，因为：
- 配置麻烦：
<bean id="/demo" class="com.ssl.controller.ControllerDemo1"/>，并且需要implements Controller - 不够灵活，太费力气，浪费时间
- 访问： http://localhost:8080/springmvc_04_controller/demo
- 配置麻烦：
public class ControllerDemo1 implements Controller {
@Override
public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
ModelAndView modelAndView = new ModelAndView();
modelAndView.addObject("demo1","demo1:Controller会返回一个modelAndView");
modelAndView.setViewName("demo1");
return modelAndView;
}
}
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3.2 @Controller
- 使用注解开发，@Controller注册进Spring容器，如果返回值是String，并且有具体的页面可以跳转，那么就会被视图解析器解析
- 访问： http://localhost:8080/springmvc_04_controller/demo2
@Controller
public class ControllerDemo2 {
@RequestMapping("/demo2")
public String test1(Model model) {
model.addAttribute("demo2", "demo2");
return "demo2";
}
}
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3.3 @RequestMapping
- 可以在类和方法上配置url访问路径
- 访问： http://localhost:8080/springmvc_04_controller/controller/demo3
@Controller
@RequestMapping("/controller")
public class ControllerDemo3 {
@RequestMapping("/demo3")
public String test1(Model model) {
model.addAttribute("demo3", "demo3");
return "demo3";
}
}
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3.4 RestFul风格
- 优点：
- 最大的优势是安全，看不出源代码的参数和意义
- 实现地址复用，使得get和post访问url相同，框架会自动进行类型转换
- 高效：支持缓存
- 缺点：
- 不像原生的url见名知意，url理解不直观
- 实现方式：
- 1：url
@GetMapping("/addRest/{a}/{b}")+ 参数@PathVariable int a, @PathVariable int b- 访问： http://localhost:8080/springmvc_04_controller/addRest/1/2
- 2：url
@PostMapping("/addRest/{a}/{b}")+ 参数不变@PathVariable int a, @PathVariable int b- 使用Postman中的post访问： http://localhost:8080/springmvc_04_controller/addRest/1/2
- 1：url
@Controller
public class RestFulController {
/**
* 原生的url：http://localhost:8080/springmvc_04/add?a=1&b=1
*/
@RequestMapping("/add")
public String getAdd1(int a, int b, Model model) {
int result = a + b;
model.addAttribute("add", "原生的url：结果为" + result);
return "add";
}
/**
* RestFul方式一：method = get
* RequestMapping("/addRest/{a}/{b}" method=requestMethod.GET) = @GetMapping()
* http://localhost:8080/springmvc_04/addRest/1/1
*/
@GetMapping("/addRest/{a}/{b}")
public String getAdd2(@PathVariable int a, @PathVariable int b, Model model) {
int result = a + b;
model.addAttribute("add", "Rest的url：结果为" + result);
return "addRest";
}
/**
* 复用相同的url
* RestFul方式二：method=post，使用RestFul的话，请求的url和GET就一样了
*/
@PostMapping("/addRest/{a}/{b}")
public String getAdd3(@PathVariable int a, @PathVariable int b, Model model) {
int result = a + b;
model.addAttribute("add", "Rest的url：结果为" + result);
return "addRest";
}
}
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3.5 重定向和转发
return “forward:xxx”/"redirect:xxx"
@Controller
public class ModelTest1 {
//原生的转发：返回值是void，没有经过视图解析器；原生的重定向同样如此，都不走视图解析器，直接重定向
@RequestMapping("/test1")
public void test1(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String id = request.getSession().getId();
System.out.println(id);
request.getRequestDispatcher("index.jsp").forward(request,response);
}
//SpringMvc转发：测试结果是不走视图解析器，url没变是转发
@RequestMapping("/test2")
public String test2(Model model) {
model.addAttribute("demo1","这是test2中的Spring转发");
return "forward:/WEB-INF/jsp/demo1.jsp";
}
//SpringMvc重定向：测试结果是不走视图解析器
@RequestMapping("/test3")
public String test3() {
System.out.println("跳转回首页index.jsp");
return "redirect:index.jsp";
}
}
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3.6 接受请求参数和数据回显
- 前端提交的name和后端映射器接受的形参名一样，则直接接受
- 前端提交的name和后端映射器接受的形参名不用一样，再形参前
@RequestParam("xxx")更改名称一致- 养成习惯：无论是否一样，都必须加上
@RequestParam
- 养成习惯：无论是否一样，都必须加上
- 后端参数封装如果成一个pojo，前端传过来的name会自动pojo中的成员属性，不匹配的属性=null/0
- 如何解决中文乱码问题？请看下节！
@Controller
public class UserController {
/** http://localhost:8080/springmvc_04/t1?id=1&name=abc&age=18
* @param user SpringMvc 会自动封装数据到参数里的pojo，不匹配的属性=null/0
*/
@GetMapping("/t1")
public String getUser(User user){
System.out.println(user);
return "test1";
}
}
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3.7 Model，ModelAndView等
- Model：精简版，适合初学者，大多数情况封装参数，设置转发视图层就够用
- ModelMap：继承了LinkedHashMap，有它的方法和特性
- ModelAndView：可以在存储数据的同时，可以进行设置返回的逻辑视图，进行控制展示层的跳转
- 怎么学习：用80%的时间学号基础，18%时间研究框架，2%学点英文，剩下不会的看官方文档
4 乱码问题
- 方法一：web.xml里面配置的SpringMvc自带的过滤器
CharacterEncodingFilter-
<url-pattern>/*</url-pattern>：因为要跳转到xxx.jsp页面，所以url是/*(≠/)
-
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!--配置SpringMVC-->
<servlet>
<servlet-name>springMvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring_mvc_servlet.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>springMvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<!--web容器解决中文乱码问题-->
<filter>
<filter-name>encode</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encode</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
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- 方法二：一劳永逸，但需要重启Tomcat服务器，修改Tomcat里面的server.xml配置文件：
URIEncoding = "UTF-8"
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443"
URIEncoding = "UTF-8"/>
<!-- A "Connector" using the shared thread pool-->
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5 JSON
5.1 前端初识Json
- 前端展示两者数据，学会js和json互相转换
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>json</title>
<script type="text/javascript">
//user是一个js对象
var user = {
name: "张三",
age: 18,
sex: "男"
};
//后端传的json其实是一个字符串，前端将后端传的json转换成js对象渲染在页面上
//jsonUser:模拟后端传的json数据
//js转换成json
var jsonUser = JSON.stringify(user);
console.log(jsonUser);
//jsUser：js是一个对象
//json转换成js
var jsUser = JSON.parse(jsonUser);
console.log(jsUser)
</script>
</head>
<body>
</body>
</html>
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5.2 Jackson Databind
- 使用 Jackson Databind可以快速生成json数据
1 导入依赖
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.10.0</version>
</dependency>
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- json=一个字符串，所以会有中文乱码问题，需要在springmvc.xml配置
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--自动扫描包，让指定包下的注解生效，由IOC容器统一管理-->
<context:component-scan base-package="com.ssl.controller"/>
<!--让SpringMvc不处理静态资源。让.css,.js等不进视图解析器-->
<mvc:default-servlet-handler/>
<!--注解加载映射器、适配器，解决Json数据中文乱码问题-->
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8"/>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
<property name="failOnEmptyBeans" value="false"/>
</bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
<!--配置视图解析器，明确json数据不走数据解析器，直接传给前端-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
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2 编写Controller
- @RestControoler:该类下所有方法不走视图解析器，返回一个json数据
- @ResponceBody：该方法不走视图解析器，返回一个json数据
- 访问： http://localhost:8080/springmvc_05_json/t1，页面显示一个json数据，不经过视图解析器
- 回顾日期：
new SimpleDateFormat("yyyy-MM-dd:HH:mm:ss")
@RestController
public class UserController {
/* 概念：前后端分离的项目，后端代码不走视图解析器，后端传给前端的是json数据
方法上：注解@ResponseBody指定该方法不走视图解析器，会直接返回一个String=json数据就是一个字符串
类上：注解@RestController指定该类下的所有方法都不走视图解析器
Json返回一个对象
*/
@RequestMapping("/t1")
public String json1() throws JsonProcessingException {
User user = new User(1, "张三", 20);
ObjectMapper jacksonMapper = new ObjectMapper();
String str_user = jacksonMapper.writeValueAsString(user);
//user.toString()是自己指定的String但是公司通常是允许的，通常是使用第三方工具来返回String
//str_user有中文乱码问题，springMvc可以统一配置
return str_user;
}
/**
* Json返回一个List
*/
@RequestMapping("/t2")
public String json2() throws JsonProcessingException {
User user1 = new User(1, "张三", 20);
User user2 = new User(2, "张三", 21);
User user3 = new User(3, "张三", 22);
User user4 = new User(4, "张三", 23);
List<User> list = new ArrayList<>();
list.add(user1);
list.add(user2);
list.add(user3);
list.add(user4);
return new ObjectMapper().writeValueAsString(list);
}
/**
* json返回一个日期格式
*/
@RequestMapping("/t3")
public String json3() throws JsonProcessingException {
//方式一：原始纯java日期转换：推荐使用
// String date = new SimpleDateFormat("yyyy-MM-dd:HH-mm-ss").format(new Date());
ObjectMapper objectMapper = new ObjectMapper();
//方式二：使用mapper来制定日期格式，先关闭时间戳表示
objectMapper.configure(SerializationFeature.WRITE_DATE_KEYS_AS_TIMESTAMPS, false);
objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd:HH:mm:ss"));
Date date = new Date();
return objectMapper.writeValueAsString(date);
}
@Test
public void DateTest1() {
//传统的java日期格式转换
String date = new SimpleDateFormat("yyyy-MM-dd:HH:mm:ss").format(new Date());
System.out.println(date);
}
}
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5.3 FastJson
- 阿里巴巴官方提供的，实现Json数据的另一个工具，比JackSon Databind更方便
1 导包
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.62</version>
</dependency>
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2 编写Controller
- 比Jackson使用更方便
@RequestMapping("/t4")
public String json4() throws JsonProcessingException {
User user1 = new User(1, "张三", 20);
User user2 = new User(2, "张三", 21);
User user3 = new User(3, "张三", 22);
User user4 = new User(4, "张三", 23);
List<User> list = new ArrayList<>();
list.add(user1);
list.add(user2);
list.add(user3);
list.add(user4);
String jsonString = JSON.toJSONString(list);
return jsonString;
}
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6 SSM整合
6.1 环境
- IDEA+Mysq5.7+Tomca5.7+Maven3.6
- 数据库
create database `ssmbuild`; use `ssmbuild`; CREATE TABLE `books` ( `bookId` int(10) NOT NULL AUTO_INCREMENT COMMENT '书id', `bookName` varchar(100) NOT NULL COMMENT '书名', `bookCounts` int(11) NOT NULL COMMENT '数量', `detail` varchar(200) NOT NULL COMMENT '描述', KEY `bookId` (`bookId`) ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8 复制代码
- pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.ssl</groupId>
<artifactId>ssmbuild</artifactId>
<version>1.0-SNAPSHOT</version>
<!--依赖:junit,数据库驱动，连接池，Servlet，jsp，mybatis,mybatis-mvc,Spring,SpringMVC-->
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
<dependency>
<groupId>com.mchange</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.5.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.2</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.0.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
</dependency>
</dependencies>
<!--Maven资源过滤设置-->
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
</build>
</project>
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6.2 开发流程
- 需求分析+设计数据库+业务+传给前端页面
- 整体效果：
6.3 整合Mybatis
- mybatis-config.xml
- 数据库连接交给Spring-dao.xml配置
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--核心配置文件-->
<configuration>
<settings>
<setting name="logImpl" value="STDOUT_LOGGING"/>
</settings>
<!--配置数据源，交给Spring去做-->
<!--取别名-->
<typeAliases>
<!--resultMap:默认类名小写为使用id-->
<package name="com.ssl.pojo"/>
</typeAliases>
<mappers>
<mapper class="com.ssl.dao.BookMapper"/>
</mappers>
</configuration>
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# db.properties配置文件 driver=com.mysql.jdbc.Driver url=jdbc:mysql://localhost:3306/ssmbuild?useSSL=false&useUnicode=true&characterEncoding=utf-8 username=root password=123456 复制代码
6.4 整合Spring
- 1 spring-dao.xml
- 数据库连接读取db.properties有bug，手动连接jdbcurl和user
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--1 关联数据库配置文件-->
<context:property-placeholder location="classpath:db.properties"/>
<!--2 连接池 这次使用c3p0的连接池.常见的数据库：
dbcp:半自动操作，不能自动连接
c3p0：自动化操作，并且可以配置到对象中
druid,hikari(SpringBoot)-->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${driver}"/>
<property name="jdbcUrl" value="${url}"/>
<property name="user" value="${username}"/>
<property name="password" value="${password}"/>
<!--c3p0的私有属性-->
<property name="maxPoolSize" value="30"/>
<property name="minPoolSize" value="10"/>
<!--关闭连接后，不自动commit-->
<property name="autoCommitOnClose" value="false"/>
<property name="checkoutTimeout" value="10000"/>
<property name="acquireRetryAttempts" value="2"/>
</bean>
<!--3 sqlSessionFactory-->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!--绑定数据库-->
<property name="dataSource" ref="dataSource"/>
<!--绑定Mybatis的配置文件-->
<property name="configLocation" value="classpath:mybatis-config.xml"/>
</bean>
<!--4 配置dao接口扫描包，动态的实现了dao接口可以注入到Spring容器中,不用写mapperImpl.xml-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!--注入sqlSessionFactory-->
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
<!--扫描要扫描的dao的包-->
<property name="basePackage" value="com.ssl.dao"/>
</bean>
</beans>
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- 2 spring-service.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--1 扫描service下的包-->
<context:component-scan base-package="com.ssl.service"/>
<!--2 将我们的所有业务类，注入到Spring,这里使用bean配置，平时是使用注解-->
<bean id="BookServiceImpl" class="com.ssl.service.BookServiceImpl">
<property name="bookMapper" ref="bookMapper"/>
</bean>
<!--3 声明式事务配置-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"/>
</bean>
<!--4 AOP横切事务，这里用不到-->
</beans>
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- 3 application.xml
- 导入其他配置进spring主配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<import resource="classpath:spring-dao.xml"/>
<import resource="classpath:spring-service.xml"/>
<import resource="classpath:spring-mvc.xml"/>
</beans>
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6.5 整合SpringMVC
- 增加web项目的支持
- web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!--SpringMVC配置-->
<!--1 DispatcherServlet-->
<servlet>
<servlet-name>springMVC</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:application.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springMVC</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<!--2 乱码过滤-->
<filter>
<filter-name>encodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!--3 Session过期时间-->
<session-config>
<session-timeout>15</session-timeout>
</session-config>
</web-app>
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- spring-mvc.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--1 注解驱动-->
<mvc:annotation-driven/>
<!--2 静态资源过滤-->
<mvc:default-servlet-handler/>
<!--3 扫描包：Controller-->
<context:component-scan base-package="com.ssl.controller"/>
<!--4 视图解析器-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
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6.6 dao层
- BookMapper接口和BookMapperMapper.xml
public interface BookMapper {
//增加一本书
int addBook(Books books);
//删除一本书
int deleteBookById(@Param("bookId") int id);
//修改一本书
int updateBook(Books books);
//查询一本书根据id
Books queryBookById(@Param("bookId")int id);
//查询全部书
List<Books> queryAllBook();
Books queryBookByName(@Param("bookName") String bookName);
}
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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--核心配置文件-->
<mapper namespace="com.ssl.dao.BookMapper">
<insert id="addBook" parameterType="Books">
insert into ssmbuild.books(bookName, bookCounts, detail)
values (#{bookName},#{bookCounts},#{detail});
</insert>
<delete id="deleteBookById" parameterType="int">
delete from ssmbuild.books where bookId = #{bookId}
</delete>
<update id="updateBook" parameterType="Books">
update ssmbuild.books set
bookName=#{bookName},
bookCounts=#{bookCounts},
detail=#{detail}
where bookId=#{bookId};
</update>
<select id="queryBookById" parameterType="int" resultType="Books">
select * from ssmbuild.books where bookId = #{bookId};
</select>
<select id="queryAllBook" resultType="Books">
select * from ssmbuild.books;
</select>
<select id="queryBookByName" parameterType="String" resultType="Books">
select * from ssmbuild.books where bookName=#{bookName}
</select>
</mapper>
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6.7 service层
public interface BookService {
//增加一本书
int addBook(Books books);
//删除一本书
int deleteBookById(int id);
//修改一本书
int updateBook(Books books);
//查询一本书根据id
Books queryBookById(int id);
//查询全部书
List<Books> queryAllBook();
Books queryBookByName(String bookName);
}
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public class BookServiceImpl implements BookService {
//注入Dao层
private BookMapper bookMapper;
public void setBookMapper(BookMapper bookMapper) {
this.bookMapper = bookMapper;
}
@Override
public int addBook(Books books) {
return bookMapper.addBook(books);
}
@Override
public int deleteBookById(int id) {
return bookMapper.deleteBookById(id);
}
@Override
public int updateBook(Books books) {
return bookMapper.updateBook(books);
}
@Override
public Books queryBookById(int id) {
return bookMapper.queryBookById(id);
}
@Override
public List<Books> queryAllBook() {
return bookMapper.queryAllBook();
}
@Override
public Books queryBookByName(String bookName) {
return bookMapper.queryBookByName(bookName);
}
}
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6.8 controller层
@Controller
@RequestMapping("/book")
public class BookController {
@Autowired
@Qualifier("BookServiceImpl")
private BookService bookService;
//查询全部的书籍，并且返回到一个书籍展示页面
@RequestMapping("/allBook")
public String list(Model model) {
List<Books> books = bookService.queryAllBook();
model.addAttribute("list", books);
return "allBook";
}
//跳转到增加书籍页面
@RequestMapping("/toAddBook")
public String toAddBook() {
return "addBook";
}
//添加书籍
@RequestMapping("/addBook")
public String addBook(Books books) {
int result = bookService.addBook(books);
if (result > 0) {
System.out.println("添加书籍成功");
}
return "redirect:/book/allBook";
}
@RequestMapping("/toUpdateBook")
public String toUpdate(int bookId, Model model) {
Books books = bookService.queryBookById(bookId);
model.addAttribute("book", books);
return "updateBook";
}
/*
没有提交事务操作，更新会失败
*/
@RequestMapping("/updateBook")
public String updateBook(Books books) {
int result = bookService.updateBook(books);
if (result > 0) {
System.out.println("修改书籍成功");
}
return "redirect:/book/allBook";
}
/*
删除书籍，回顾RestFul风格
*/
@RequestMapping("/deleteBook/{bookId}")
public String deleteBook(@PathVariable("bookId") int bookId) {
int result = bookService.deleteBookById(bookId);
if (result > 0) {
System.out.println("删除书籍成功");
}
return "redirect:/book/allBook";
}
@RequestMapping("/queryBook")
public String queryBook(String queryBookName, Model model) {
Books books = bookService.queryBookByName(queryBookName);
//复用，这样就显示一个
List<Books> list = new ArrayList<>();
list.add(books);
if (books == null) {
list= bookService.queryAllBook();
model.addAttribute("errMsg","未查任何书籍");
}
model.addAttribute("list", list);
return "allBook";
}
}
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6.9 前端页面
index.xml
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
<style>
/*消除字体蓝色下划线*/
a {
text-decoration: none;
color: black;
font-size: 18px;
}
h3 {
width: 180px;
height: 38px;
margin: 100px auto;
text-align: center;
line-height: 38px;
background: deepskyblue;
border-radius: 5px;
}
</style>
</head>
<body>
<h3>
<a href="${pageContext.request.contextPath}/book/allBook">进入书籍展示页面</a>
</h3>
</body>
</html>
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WEB-INF/jsp/addBook.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
<%--BootStrap美化界面--%>
<link href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
<div class="row clearfix">
<%--屏幕分成12列--%>
<div class="col-md-12 column">
<div class="page-header">
<h1>
<small>新增书籍</small>
</h1>
</div>
</div>
</div>
<%--BootStrap官网拿"表单"数据 name属性保证pojo属性名称一致 required保证必须提交--%>
<form action="${pageContext.request.contextPath}/book/addBook" method="post">
<div class="form-group">
<label for="bName">书籍名称:</label>
<input type="text" name="bookName" class="form-control" id="bName" required>
</div>
<div class="form-group">
<label for="bCount">书籍数量：</label>
<input type="text" name="bookCounts" class="form-control" id="bCount" required>
</div>
<div class="form-group">
<label for="bDesc">书籍描述：</label>
<input type="text" name="detail" class="form-control" id="bDesc" required>
</div>
<div class="form-group">
<input type="submit" class="form-control" value="添加">
</div>
</form>
</head>
<body>
</body>
</html>
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WEB-INF/jsp/allBook.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>书籍展示页面</title>
<%--BootStrap美化界面--%>
<link href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div class="container">
<div class="row clearfix">
<%--屏幕分成12列--%>
<div class="col-md-12 column">
<div class="page-header">
<h1>
<small> 书籍列表——————————显示所有书籍</small>
</h1>
</div>
</div>
<div class="row">
<div class="col-md-4 column">
<a class="btn btn-primary" href="${pageContext.request.contextPath}/book/toAddBook">新增书籍</a>
<a class="btn btn-primary" href="${pageContext.request.contextPath}/book/allBook">显示全部书籍</a>
</div>
<div class="col-md-4 column"></div>
<div class="col-md-8 column">
<form action="${pageContext.request.contextPath}/book/queryBook" method="post" style="float: right">
<%--前端未传任何信息，就显示错误提示信息：未查任何书籍--%>
<span style="color: red;font-weight: bold">${errMsg}</span>
<%--class="form-inline"保证在同一行--%>
<input type="text" name="queryBookName" class="form-inline" placeholder="请输入要查询的书籍名称">
<input type="submit" value="查询" class="btn btn-primary">
</form>
</div>
</div>
</div>
<div class="row clearfix">
<div class="col-md-12 column">
<table class="table table-hover table-striped">
<thead>
<tr>
<th>书籍编号</th>
<th>书籍名称</th>
<th>书籍数量</th>
<th>书籍详情</th>
<th>操作</th>
</tr>
</thead>
<%--书籍从数据库中查询出来，从这个list中遍历出来，foreach--%>
<tbody>
<c:forEach var="book" items="${list}">
<tr>
<td>${book.bookId}</td>
<td>${book.bookName}</td>
<td>${book.bookCounts}</td>
<td>${book.detail}</td>
<td>
<a href="${pageContext.request.contextPath}/book/toUpdateBook?bookId=${book.bookId}">修改</a>
|
<a href="${pageContext.request.contextPath}/book/deleteBook/${book.bookId}">删除</a>
</td>
</tr>
</c:forEach>
</tbody>
</table>
</div>
</div>
</div>
</body>
</html>
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WEB-INF/jsp/updateBook.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
<%--BootStrap美化界面--%>
<link href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
<div class="row clearfix">
<%--屏幕分成12列--%>
<div class="col-md-12 column">
<div class="page-header">
<h1>
<small>修改书籍</small>
</h1>
</div>
</div>
</div>
<%--BootStrap官网拿"表单"数据 name属性保证pojo属性名称一致 required保证必须提交--%>
<form action="${pageContext.request.contextPath}/book/updateBook" method="post">
<%--提交失败：没有回显：问题：
1. 事务没有提交
2. sql执行失败，没有提交BookId，需要前端的隐藏域
--%>
<%--添加bookId的隐藏域--%>
<input type="hidden" name="BookId" value="${book.bookId}">
<div class="form-group">
<label for="bName">书籍名称:</label>
<input type="text" name="bookName" class="form-control" id="bName" value="${book.bookName}" required>
</div>
<div class="form-group">
<label for="bCount">书籍数量：</label>
<input type="text" name="bookCounts" class="form-control" id="bCount" value="${book.bookCounts}"required>
</div>
<div class="form-group">
<label for="bDesc">书籍描述：</label>
<input type="text" name="detail" class="form-control" id="bDesc" value="${book.detail}" required>
</div>
<div class="form-group">
<input type="submit" class="form-control" value="添加">
</div>
</form>
</head>
<body>
</body>
</html>
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7 Ajax
7.1 概念
- Ajax就是一个异步无刷新请求，无需更新整个页面就异步加载一些数据，交互性更强
- 模拟异步请求
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>模拟Ajax异步请求</title>
<script>
function go() {
var url = document.getElementById("url").value;
document.getElementById("iframe1").src = url;
}
</script>
</head>
<body>
<div>
<p>请输入地址：</p>
<p>
<input type="text" id="url">
<input type="button" id="button" value="提交" onclick="go()">
</p>
</div>
<div>
<iframe id="iframe1" style="width:100%;height: 500px">
</iframe>
</div>
</body>
</html>
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7.2 使用JQ使用Ajax
1 初试Ajax
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
<%--加载动态的JQ资源--%>
<script src="https://code.jquery.com/jquery-3.4.1.js"></script>
<script>
/*
AJax后盾必须懂的东西：
url：后端接受的地址
data：后端接受到的请求参数，json数据格式=前后端分离时候，后端传的数据便于前端接受就是json数据
success:后端接受成功返回的函数
error:后盾失败接受返回的函数
*/
function username() {
$.post({
url: "${pageContext.request.contextPath}/a1",
data: {"name": $("#username").val()},
success: function (data, status) {
console.log("data:" + data);
console.log("status:" + status);
}
})
}
</script>
</head>
<body>
<%--实现Ajax异步请求
1 绑定单击事件
2 单击事件函数使用Jq：$.post({})
--%>
用户名:<input type="text" id="username" onclick="username()">
</body>
</html>
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2 Ajax实现异步加载
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Ajax</title>
<script src="https://code.jquery.com/jquery-3.4.1.js"></script>
<script>
/*页面加载完*/
$(function () {
/*绑定btn单击事件*/
$("#btn").click(function () {
/*JQ使用Ajax异步请求*/
$.post("${pageContext.request.contextPath}/a2", function (data) {
// data接受返回的值
//console.log(data);
var html = "";
for (let i = 0; i < data.length; i++) {
html += "<tr>" +
"<td>" + data[i].name + "</td>" +
"<td>" + data[i].age + "</td>" +
"<td>" + data[i].sex + "</td>" +
+"<tr>"
}
$("#content").html(html);
});
});
})
</script>
</head>
<body>
<input type="button" id="btn" value="加载数据">
<table>
<tr>
<td>姓名</td>
<td>年龄</td>
<td>性别</td>
</tr>
<tbody id="content">
</tbody>
</table>
</body>
</html>
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3 实现登录验证
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>login</title>
<script src="https://code.jquery.com/jquery-3.4.1.js"></script>
<script>
function nameFun() {
$.post({
url: "${pageContext.request.contextPath}/a3",
data: {"name": $("#name").val()},
success: function (data) {
//console.log(data);
if (data.toString() === "用户名成功") {
$("#userInfo").css("color", "green");
} else {
$("#userInfo").css("color", "red");
}
$("#userInfo").html(data);
}
})
}
function passwordFun() {
$.post({
url: "${pageContext.request.contextPath}/a3",
data: {"password": $("#password").val()},
success: function (data) {
if (data.toString() === "密码正确") {
$("#userPasswordInfo").css("color", "green");
}else {
$("#userPasswordInfo").css("color", "red");
}
$("#userPasswordInfo").html(data);
}
})
}
</script>
</head>
<body>
<p>
用户名:<input type="text" id="name" onclick="nameFun()">
<%--span提示信息--%>
<span id="userInfo"></span>
</p>
<p>
用户密码:<input type="password" id="password" onclick="passwordFun()">
<span id="userPasswordInfo"></span>
</p>
</body>
</html>
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appliacation.xml添加json乱码问题
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--1 自动扫描包，让指定包下的注解生效，由IOC容器统一管理-->
<context:component-scan base-package="com.ssl.controller"/>
<!--2 注解驱动-->
<mvc:annotation-driven/>
<!-- 使用JQ，使用静态资源过滤需要引用，动态就不需要-->
<mvc:default-servlet-handler/>
<!--注解加载映射器、适配器，解决Json数据中文乱码问题-->
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8"/>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
<property name="failOnEmptyBeans" value="false"/>
</bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
<!--3 以上的是定死的代码，以下是配置视图解析器-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
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7.3 后端需要的前端知识
- HTML+CSS+Js（超级熟练）
- Js必会？：
- 函数闭包？
- DOM
- id,name.tag
- create,remove
- BOM：浏览器对象模型
- window
- document
8 拦截器
8.1 概念
- 数据独立性：Servlet中的是过滤器，而拦截器是SpringMVC框架独有的，独享request和response
- 拦截器只会拦截访问的控制器方法，如果访问的是jsp/html/css等式不会拦截的
- 拦截器是基于AOP思想的，和AOP实现是一样的，在application.xml中配置
<!--拦截器配置-->
<mvc:interceptors>
<mvc:interceptor>
<!--
/**是拦截之后所有的请求，比如/admin/a1/2131
-->
<mvc:mapping path="/**"/>
<bean class="com.ssl.config.MyInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
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8.2 自定义拦截器
- 实现 HandlerInterceptor
public class MyInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
//return true：执行下一个拦截器
System.out.println("===========处理前,这里进行拦截处理=================");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("===========处理后，通常进行日志管理=================");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("===========清洁中=================");
}
}
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- applica.xml配置
<!--拦截器配置-->
<mvc:interceptors>
<mvc:interceptor>
<!--
/**是拦截之后所有的请求，比如/admin/a1/2131
-->
<mvc:mapping path="/**"/>
<bean class="com.ssl.config.MyInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
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8.3 登录验证判断
public class LoginInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
HttpSession session = request.getSession();
request.getRequestURL();
//URL:http://localhost:8080/springmvc_07_interceptor/user//main
System.out.println("URL:" + request.getRequestURL());
//URI:/springmvc_07_interceptor/user//main
System.out.println("URI:" + request.getRequestURI());
if (session.getAttribute("username") == null || session.getAttribute("password") == null) {
request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);
} else if (session.getAttribute("username").equals("admin") && session.getAttribute("password").equals("123456")) {
return true;
}
if (request.getRequestURI().contains("ogin")) {
return true;
}
request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);
return false;
}
}
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@Controller
@RequestMapping("/user")
public class LoginController {
@RequestMapping("/main")
public String main() {
//沒登陸就不等進入首頁
return "main";
}
@RequestMapping("/goLogin")
public String goLogin() {
return "login";
}
@RequestMapping("/login")
public String login(String username, String password, HttpSession session, Model model) {
session.setAttribute("username", username);
session.setAttribute("password", password);
model.addAttribute("username", username);
return "main";
}
@RequestMapping("/outUser")
public String outUser(HttpSession session) {
session.removeAttribute("username");
session.removeAttribute("password");
return "main";
}
}
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9 文件上传
- 前端form添加enctype="multipart/form-data",method="post"
<form enctype="multipart/form-data" method="post" action="">
</form>
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- 后端pom导包
<dependencies>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.4</version>
</dependency>
<!--导入高版本的api-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
</dependency>
</dependencies>
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- Spring自带的文件上传,application.xml配置
<!--4 文件上传配置-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="defaultEncoding" value="utf-8"/>
<!--最大上传大小：单位是1字节-->
<property name="maxUploadSize" value="10485760"/>
<property name="maxInMemorySize" value="40960"/>
</bean>
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@RestController
public class FileController {
@RequestMapping("/upFile")
public String upFile(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
//设置文件保存路径
String path = request.getServletContext().getRealPath("/upload");
System.out.println("path:" + path);
File realPath = new File(path);
if (!realPath.exists()) {
realPath.mkdir();
}
System.out.println("上传的文件地址：" + realPath);
//CommonsMultipartFile的方法写文件，简化
file.transferTo(new File(realPath + "/" + file.getOriginalFilename()));
return "redirect:/index.jsp";
}
}
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10 文件下载
- 方式一：写方法下载
@RequestMapping(value = "/download")
public String downLoad(HttpServletResponse response, HttpServletRequest request) throws IOException {
//手动设置，要下载的图片地址
String path = request.getServletContext().getRealPath("/upload");
String fileName = "1.png";
//设置响应头
response.reset();//设置页面不缓存，清空buffer
response.setCharacterEncoding("UTF-8");
response.setContentType("multipart/form-data");//二进制传输数据
response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8"));
File file = new File(path, fileName);
//读取文件-输入流
InputStream input = new FileInputStream(file);
//写入文件-输出流
OutputStream out = response.getOutputStream();
byte[] buff = new byte[1024];
int index = 0;
while ((index = input.read(buff)) != -1) {
out.write(buff,0,index);
out.flush();
}
input.close();
out.close();
return "redirect:/index.jsp";
}
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- 方式二： 标签直接web下静态获取
正文到此结束
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