SpringBoot自定义拦截器

1、创建自定义拦截器类

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   package cn.woniu.myInterseption;
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   import org.springframework.lang.Nullable;
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   import org.springframework.web.bind.annotation.ExceptionHandler;
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   import org.springframework.web.servlet.HandlerInterceptor;
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   import org.springframework.web.servlet.ModelAndView;
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   import javax.servlet.http.HttpServletRequest;
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   import javax.servlet.http.HttpServletResponse;
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    public class MyIntercepror implements HandlerInterceptor {
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    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
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    System.out.println("在controller之前执行!!!!");
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    return true;
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    //HandlerInterceptor.super.preHandle(request, response, handler);
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    }
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    /**
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    * value: 只有抛出指定异常类型,才会被该方法捕捉到
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    * @return
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    */
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    @ExceptionHandler(value = {java.lang.ArithmeticException.class})
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    public ModelAndView mdv(){
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    ModelAndView modelAndView = new ModelAndView();
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    modelAndView.setViewName("error1");
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    return modelAndView;
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    }
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    /**
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    * 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
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    * * @param request
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    * @param response
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    * @param handler
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    * @param modelAndView
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    * @throws Exception
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    */
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    @Override
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    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
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    System.out.println("返回页面前");
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    HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
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    }
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    /**
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    * 页面已经返回后执行
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    * @param request
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    * @param response
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    * @param handler
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    * @param ex
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    * @throws Exception
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    */
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    @Override
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    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
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    System.out.println("页面返回后!!!!");
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    HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
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    }
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    }
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2、配置拦截器

创建springmvc配置类

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

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/"

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

• 修改拦截器注册方法

 返回类

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

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 

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