转载

Spring MVC拦截器学习

1 介绍

Spring Web MVC是基于Servlet API构建的原始Web框架。

2 拦截器

2.1 定义

springmvc框架的一种拦截机制

2.2 使用

2.2.1 两步走

实现HandlerInterceptor接口
注册（xml或者注解）

2.2.2 HandlerInterceptor接口

Spring MVC拦截器学习

实现HandlerInterceptor接口

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class InterceptorTest implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle");
        return true; // 只有返回true才会继续向下执行，返回false取消当前请求
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion");
    }
}

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

/**
 * 注册拦截器(扫描到拦截器)
 */
@Configuration
public class MyWebAppConfigurer extends WebMvcConfigurerAdapter {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new InterceptorTest()).addPathPatterns("/**");
        super.addInterceptors(registry);
    }
}