Spring 配置拦截器 HandlerInterceptor

比眉伴天荒 2022-06-08 04:58 712阅读 0赞

**目录**

1、Spring基础环境搭建（略）

2、过滤器类实现 HandlerInterceptor 接口

3、mvc:interceptors 配置

4、拦截器访问顺序

5、看看我们的测试方法-线程暂停1000毫秒

6、实验打印结果

7、执行顺序

过滤器-拦截器（preHandle方法）-被调用程序运行结束-拦截器（postHandle方法）-拦截器（afterCompletion方法）

8、延伸阅读-使用拦截器或者过滤器修改 request 的参数值

9、获取所有的入参

--------------------

## 1、Spring基础环境搭建（略） ##

## 2、过滤器类实现 HandlerInterceptor 接口 ##

不要对里面的 maxSize 参数感到奇怪，他是可有可无的，其来自于xml配置中配置的参数，看下一步

preHandle return false 时程序就会中止

如果想要页面跳转到一个单独到页面可以

response.sendRedirect(request.getContextPath() + "/路径");
    return false;

package com.bestcxx.stu.fileup.intercepter;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.apache.commons.fileupload.servlet.ServletFileUpload;
    import org.apache.commons.fileupload.servlet.ServletRequestContext;
    import org.springframework.web.multipart.MaxUploadSizeExceededException;
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    public class MyInterceptor implements HandlerInterceptor {
    	private long maxSize;
    
    	@Override
    	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
    			throws Exception {
    		System.out.println(this.getClass()+" preHandle开始："+System.currentTimeMillis());
    		System.out.println(this.getClass()+" 自定义拦截器访问前："+maxSize);
    		 if(request!=null && ServletFileUpload.isMultipartContent(request)) {
    	            ServletRequestContext ctx = new ServletRequestContext(request);
    	            long requestSize = ctx.contentLength();
    	            if (requestSize > maxSize) {
    	                throw new MaxUploadSizeExceededException(maxSize);
    	            }
    	        }
    		System.out.println(this.getClass()+" preHandle结束："+System.currentTimeMillis());
    		return true;
    		
    	}
    
    	@Override
    	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
    			ModelAndView modelAndView) throws Exception {
    		// TODO Auto-generated method stub
    		System.out.println(this.getClass()+" postHandle开始："+System.currentTimeMillis());
    		System.out.println(this.getClass()+" 自定义拦截器访问中："+maxSize);
    		System.out.println(this.getClass()+" postHandle结束："+System.currentTimeMillis());
    		
    	}
    
    	@Override
    	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
    			throws Exception {
    		// TODO Auto-generated method stub
    		System.out.println(this.getClass()+" afterCompletion开始："+System.currentTimeMillis());
    		System.out.println(this.getClass()+" 自定义拦截器访问后："+maxSize);
    		System.out.println(this.getClass()+" afterCompletion结束："+System.currentTimeMillis());
    
    	}
    
    	public void setMaxSize(long maxSize) {
    		this.maxSize = maxSize;
    	}
    	
    	
    
    }

## 3、mvc:interceptors 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:tx="http://www.springframework.org/schema/tx"  
        xmlns:aop="http://www.springframework.org/schema/aop"  
        xmlns:util="http://www.springframework.org/schema/util"  
        xmlns:orm="http://www.springframework.org/schema/orm"   
        xmlns:mvc="http://www.springframework.org/schema/mvc"  
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd  
                            http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd  
                            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd  
                            http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd  
                            http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.3.xsd  
                            http://www.springframework.org/schema/orm http://www.springframework.org/schema/orm/spring-orm-4.3.xsd  
                            http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd  
        ">
        
         <mvc:interceptors>
         	<mvc:interceptor>
         		<mvc:mapping path="/**"/>
         		<bean class="com.bestcxx.stu.fileup.intercepter.MyInterceptor">
         			<property name="maxSize" value="5000"></property>
         		</bean>
         	</mvc:interceptor>
         </mvc:interceptors>
        
    </beans>

## 4、拦截器访问顺序 ##

访问-过滤器-拦截器（访问前，中，后三个方法都会被调用）

## 5、看看我们的测试方法-线程暂停1000毫秒 ##

@GetMapping(value="restfulGetResponseBody")
    	@ResponseBody
    	public AjaxRespnseModel<String> restfulGetResponseBody(){
    		System.out.println(this.getClass()+" restfulGetResponseBody开始："+System.currentTimeMillis());
    		AjaxRespnseModel<String> a=new AjaxRespnseModel<String>();
    		a.setResult("RESTful风格测试");
    		a.setMsg("RESTful风格测试,仅仅用户测试get方法。");
    		
    		//线程停止1000毫秒
    		try {
    			Thread.sleep(1000);
    		} catch (InterruptedException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		System.out.println(this.getClass()+" restfulGetResponseBody结束："+System.currentTimeMillis());
    		return a;
    	}

## 6、实验打印结果 ##

不要在意第一行，那个是我写的一个filter，不过可以认为，Filter是限于interceptor执行的

class com.bestcxx.stu.fileup.filter.MyFilter 自定义路过的filter
    class com.bestcxx.stu.fileup.intercepter.MyInterceptor preHandle开始：1505445860408
    class com.bestcxx.stu.fileup.intercepter.MyInterceptor 自定义拦截器访问前：5000
    class com.bestcxx.stu.fileup.intercepter.MyInterceptor preHandle结束：1505445860408
    class com.bestcxx.stu.fileup.controller.RestfulController restfulGetResponseBody开始：1505445860411
    class com.bestcxx.stu.fileup.controller.RestfulController restfulGetResponseBody结束：1505445861411
    class com.bestcxx.stu.fileup.intercepter.MyInterceptor postHandle开始：1505445861475
    class com.bestcxx.stu.fileup.intercepter.MyInterceptor 自定义拦截器访问中：5000
    class com.bestcxx.stu.fileup.intercepter.MyInterceptor postHandle结束：1505445861475
    class com.bestcxx.stu.fileup.intercepter.MyInterceptor afterCompletion开始：1505445861475
    class com.bestcxx.stu.fileup.intercepter.MyInterceptor 自定义拦截器访问后：5000
    class com.bestcxx.stu.fileup.intercepter.MyInterceptor afterCompletion结束：1505445861475

## 7、执行顺序 ##

### 过滤器-拦截器（preHandle方法）-被调用程序运行结束-拦截器（postHandle方法）-拦截器（afterCompletion方法） ###

## 8、延伸阅读-使用拦截器或者过滤器修改 request 的参数值 ##

在实际访问中，有时候我们会遇到参数需要处理的情况，比如数字隐藏，加密解密等，这个时候需要对传递中的参数进行二次处理

使用拦截器(org.springframework.web.servlet.HandlerInterceptor)和过滤器(javax.servlet.Filter)都可以实现这个功能

过滤器 中

@Override
        public void doFilter(ServletRequest request, 
    ServletResponse response, FilterChain chain) throws IOException, ServletException {
            request.getParameterMap().put("参数名",新值);
            chain.doFilter(request,response);
        }

拦截器中

@Override
        public boolean preHandle(HttpServletRequest request,
     HttpServletResponse response, Object handler) throws Exception {
            request.getParameterMap().put("参数名",新值);
            return true;
        }

由于本文是拦截器的，所以附上过滤器的配置-web.xml 中增加

<filter>
    		<filter-name>myFilter</filter-name>
    		<filter-class>**.filter.MyFilter</filter-class>
    	</filter>
    	<filter-mapping>
    		<filter-name>myFilter</filter-name>
    		<url-pattern>/a/b/*</url-pattern>
    	</filter-mapping>

## 9、获取所有的入参 ##

Set<String> set=request.getParameterMap().keySet();
    
            Iterator iterator=set.iterator();
            while(iterator.hasNext()){
                logger.info(iterator.next());
            }