SpringBoot自定义拦截器

1、创建自定义拦截器类

package cn.woniu.myInterseption;
 
import org.springframework.lang.Nullable;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class MyIntercepror implements HandlerInterceptor {
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("在controller之前执行!!!!");
        return true;
                //HandlerInterceptor.super.preHandle(request, response, handler);
    }
 
    /**
     * value: 只有抛出指定异常类型,才会被该方法捕捉到
     * @return
     */
    @ExceptionHandler(value = {java.lang.ArithmeticException.class})
    public ModelAndView mdv(){
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("error1");
        return modelAndView;
    }
 
    /**
     * 在业务代码执行完了但是还没有执行试图解析器,意思就是还没有返回页面前执行
     * * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("返回页面前");
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }
 
    /**
     * 页面已经返回后执行
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("页面返回后!!!!");
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
    }
 
 
 

2、配置拦截器

创建springmvc配置类

package cn.woniu.configuration;
 
import cn.woniu.myInterseption.MyIntercepror;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class MyMvcHandler implements WebMvcConfigurer {
    public void addInterceptors(InterceptorRegistry registry) {
    registry.addInterceptor(new MyIntercepror())//将我们自定义拦截器
        .addPathPatterns("/**")//所有路径都拦截
        .excludePathPatterns("/","/login");//配置不需要拦截的url
    }
}

配置拦截器后会造成页面静态资源无法加载的问题

• 修改配置文件

  #配置mvc静态资源目录  不配置默认为"/**" spring.mvc.static-path-pattern=/static/**
  

• 修改页面静态资源引用

要加上"/satic/"

<link href='/static/bootstrap/css/bootstrap.css' rel="stylesheet">
<script type="text/javascript" src='/static/js/jquery-3.5.1.js'></script>
<script type="text/javascript" src='/static/bootstrap/js/bootstrap.js'></script>

• 修改拦截器注册方法

 返回类

package cn.woniu.controller;
 
import cn.woniu.entity.Users;
import org.apache.ibatis.jdbc.Null;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
 
@RestController
public class HandlerController {
    @RequestMapping("/hhh")
    public String testExcepition(){
        int  i =1/0;
//        Users users=null;
//        users.getId();
        throw new NullPointerException();
        //return "111";
    }
 
 
 
    @RequestMapping(value="/login")
    public String login(){
 
        return "login";
    }
    @RequestMapping(value="/index" )
    public String index(){
        System.out.println("执行controller方法");
        return "index";
    }
}

访问login,显示拦截

 

释放通行后,得到返回值 

 

我们在哪里控制放行和关闭,就是拦截器第一个方法的返回值,true为放行,false为关闭