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SpringBoot 2.0 + Mybatis + Mybatis Generator + IDEA 制作多数据源

SpringBoot 2.0 + Mybatis + Mybatis Generator + 多数据源 + IDEA

吐槽

昨天网上找了个“完整”版的使用 SpringBoot 2.0 + Mybatis 实现多数据源，结果其实是缺少部分代码的，被害得很惨，浪费了太多时间，找了N多教程后最终集成成功，赶紧文章整理出来。

开发环境、技术栈

使用IDEA，集成了下面的功能点：SpringBoot 2.0 + Mybatis + Mybatis Generator + XML

以XML的形式和数据库交互，而不是使用注解的方式，项目之后遇到复杂的SQL语句还是XML形式方便

项目制作步骤

使用 IDEA 创建 SpringBoot 2.0 项目的过程略过

pom.xml 的全部代码：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.xdf</groupId>
    <artifactId>multd</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>multd</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.0</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>

            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <configuration>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
            </plugin>


        </plugins>
    </build>

</project>

解释项目结构

本来想在图片中标注每个包、文件的作用，看看太多了，还是文字表达吧。controller 存放控制器类，com.xdf.multd.dao.test1 和 com.xdf.multd.dao.test2 分别存放两个数据库对应的 dao 类，com.xdf.multd.datasource 存放两个数据库对应的数据库连接，将两个数据库表对应的ORM类的都存放在包com.xdf.multd.model 中，com.xdf.multd.service 自然是服务层了。

下面讲解 resources 目录下的文件：

mapper 是 Mybatis Generator 生成的 mapper 文件存放的位置，生成后要对应的拷贝到 mappers.test1 或者 mappers.test2 中，下面的3个文件 application.yml、application-dev.yml、application-mult.yml 是多环境配置，generatorConfig.xml 是 Mybatis Generator 的相关参数，mybatis-config.xml 是映射ORM时数据类型的对应关系，最后一个 mysql-connector-java-5.1.34.jar 是 Mybatis Generator 链接数据库时要用到的驱动。

application.yml 的全部代码：

spring:
  profiles:
    active: mult

application-mult.yml 的全部代码：

server:
  port: 8083

# mybatis generator 的配置
mybatis:
  config-location: classpath:mybatis-config.xml
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.xdf.multd.model


spring:
  datasource:
    test1:
      driver-class-name: com.mysql.cj.jdbc.Driver
      jdbc-url: jdbc:mysql://localhost:3306/femis?userUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
      username: root
      password: chanchaw
    test2:
      driver-class-name: com.mysql.cj.jdbc.Driver
      jdbc-url: jdbc:mysql://localhost:3306/femisimg?userUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
      username: root
      password: chanchaw

mybatis-config.xml 的全部代码：

<?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">
<configuration>
    <settings>
        <setting name="callSettersOnNulls" value="true"/>
        <setting name="cacheEnabled" value="true"/>
        <setting name="lazyLoadingEnabled" value="true"/>
        <setting name="aggressiveLazyLoading" value="true"/>
        <setting name="multipleResultSetsEnabled" value="true"/>
        <setting name="useColumnLabel" value="true"/>
        <setting name="useGeneratedKeys" value="false"/>
        <setting name="autoMappingBehavior" value="PARTIAL"/>
        <setting name="defaultExecutorType" value="SIMPLE"/>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
        <setting name="localCacheScope" value="SESSION"/>
        <setting name="jdbcTypeForNull" value="NULL"/>
    </settings>
    <typeAliases>
        <typeAlias alias="Integer" type="java.lang.Integer" />
        <typeAlias alias="Long" type="java.lang.Long" />
        <typeAlias alias="HashMap" type="java.util.HashMap" />
        <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" />
        <typeAlias alias="ArrayList" type="java.util.ArrayList" />
        <typeAlias alias="LinkedList" type="java.util.LinkedList" />
    </typeAliases>
</configuration>

generatorConfig.xml 的全部代码：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<!-- 配置生成器 -->
<generatorConfiguration>

    <!--classPathEntry:数据库的JDBC驱动,换成你自己的驱动位置 可选 -->
    <!--<classPathEntry location="E:/IdeaProjects/mysql-connector-java-5.1.47.jar"/>-->
    <classPathEntry location="D:/Java/ideaProject/multd/src/main/resources/mysql-connector-java-5.1.34.jar"/>

    <!-- 一个数据库一个context,defaultModelType="flat" 大数据字段，不分表 -->
    <context id="MysqlTables" targetRuntime="MyBatis3Simple" defaultModelType="flat">

        <!-- 自动识别数据库关键字，默认false，如果设置为true，根据SqlReservedWords中定义的关键字列表；一般保留默认值，遇到数据库关键字（Java关键字），使用columnOverride覆盖 -->
        <property name="autoDelimitKeywords" value="true"/>

        <!-- 生成的Java文件的编码 -->
        <property name="javaFileEncoding" value="utf-8"/>

        <!-- beginningDelimiter和endingDelimiter：指明数据库的用于标记数据库对象名的符号，比如ORACLE就是双引号，MYSQL默认是`反引号； -->
        <property name="beginningDelimiter" value="`"/>
        <property name="endingDelimiter" value="`"/>

        <!-- 格式化java代码 -->
        <property name="javaFormatter" value="org.mybatis.generator.api.dom.DefaultJavaFormatter"/>

        <!-- 格式化XML代码 -->
        <property name="xmlFormatter" value="org.mybatis.generator.api.dom.DefaultXmlFormatter"/>
        <plugin type="org.mybatis.generator.plugins.SerializablePlugin"/>
        <plugin type="org.mybatis.generator.plugins.ToStringPlugin"/>

        <!-- 注释 -->
        <commentGenerator>
            <property name="suppressAllComments" value="true"/><!-- 是否取消注释 -->
            <property name="suppressDate" value="false"/> <!-- 是否生成注释代时间戳-->
        </commentGenerator>

        <!-- jdbc连接-->
        <!--<jdbcConnection driverClass="com.mysql.jdbc.Driver"-->
                        <!--connectionURL="jdbc:mysql://localhost:3306/femis?serverTimezone=UTC" userId="root"-->
                        <!--password="chanchaw"/>-->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/femisimg?serverTimezone=UTC" userId="root"
                        password="chanchaw"/>

        <!-- 类型转换 -->
        <javaTypeResolver>
            <!-- 是否使用bigDecimal， false可自动转化以下类型（Long, Integer, Short, etc.） -->
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>

        <!-- 生成实体类地址 -->
        <javaModelGenerator targetPackage="com.xdf.multd.model" targetProject="src/main/java">
            <!-- 是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false"/>
            <!-- 从数据库返回的值去掉前后空格 -->
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!-- 生成map.xml文件存放地址 -->
        <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources">
            <property name="enableSubPackages" value="false"/>
        </sqlMapGenerator>

        <!-- 生成接口dao -->
        <javaClientGenerator targetPackage="com.xdf.multd.dao" targetProject="src/main/java" type="XMLMAPPER">
            <property name="enableSubPackages" value="false"/>
        </javaClientGenerator>

        <!-- table可以有多个,每个数据库中的表都可以写一个table，tableName表示要匹配的数据库表,也可以在tableName属性中通过使用%通配符来匹配所有数据库表,只有匹配的表才会自动生成文件 enableSelectByPrimaryKey相应的配置表示是否生成相应的接口 -->
        <table tableName="orderimg" enableCountByExample="false" enableUpdateByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"
               enableSelectByPrimaryKey="true" enableUpdateByPrimaryKey="true"
               enableDeleteByPrimaryKey="true">
            <property name="useActualColumnNames" value="true"/>
        </table>

    </context>
</generatorConfiguration>

为两个数据库创建对应的数据源，两个文件都放在 com.xdf.multd.datasource 下，其中 DataSource1Config 对的全部代码如下：

package com.xdf.multd.datasource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.xdf.multd.dao.test1", sqlSessionTemplateRef  = "test1SqlSessionTemplate")
public class DataSource1Config {

    @Bean(name = "test1DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.test1")
    @Primary
    public DataSource testDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "test1SqlSessionFactory")
    @Primary
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("test1DataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        //添加XML目录
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try {
            bean.setMapperLocations(resolver.getResources("classpath*:mappers/test1/*.xml"));
            return bean.getObject();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }

    }

    @Bean(name = "test1TransactionManager")
    @Primary
    public DataSourceTransactionManager testTransactionManager(@Qualifier("test1DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "test1SqlSessionTemplate")
    @Primary
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

DataSource2Config 的全部代码如下：

package com.xdf.multd.datasource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.xdf.multd.dao.test2", sqlSessionTemplateRef  = "test2SqlSessionTemplate")
public class DataSource2Config {

    @Bean(name = "test2DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.test2")
    public DataSource testDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "test2SqlSessionFactory")
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("test2DataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try {
            bean.setMapperLocations(resolver.getResources("classpath*:mappers/test2/*.xml"));
            return bean.getObject();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    @Bean(name = "test2TransactionManager")
    public DataSourceTransactionManager testTransactionManager(@Qualifier("test2DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "test2SqlSessionTemplate")
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}