自定义拦截器

springmvc可以使用拦截器对请求进行拦截处理，用户可以自定义拦截器来实现特定功能

自定义拦截器必须实现HandlerInterceptor接口

-preHandle():这个方法在业务处理器处理请求之前被调用，在该方法中对用户请求request

进行处理。如果你决定该拦截器对请求进行拦截处理后还要调用其他拦截器，或者业务处理器

去进行处理，则返回true；如果你决定不需要再调用其他组件处理请求，则返回false

-postHandle():这个方法在业务处理器处理完请求后，但是DispatchServlet向客户端返回

响应前被调用，在该方法中对用户请求request进行处理

-afterCompletion():这个方法在DispatchServlet完全处理完请求后被调用，可以在该方法中

进行一些资源清理操作

 

 

多个拦截器执行顺序

 

package com.hous.crud.interceptor;

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

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

public class FirstInterceptor implements HandlerInterceptor {

	/* 
	 * 该方法在目标方法之前被调用
	 * 若返回值为true，则继续调用后续的拦截器和目标方法
	 * 若返回值为false，则不会再调用后续的拦截器和目标方法
	 * 
	 * 可以考虑做权限，日志，事务等
	 */
	@Override
	public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception {
		System.out.println("[FirstInterceptor]preHandle");
		return true;
	}
	
	/* 
	 * 调用目标方法之后，渲染视图之前
	 * 可以对请求域中的属性或视图做出修改
	 */
	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object arg2, ModelAndView mv)
			throws Exception {
//		System.out.println(mv.getViewName());
		System.out.println(request.getRequestURI());
		System.out.println("[FirstInterceptor]postHandle");
	}

	/* 
	 * 渲染视图之后被调用，释放资源
	 */
	@Override
	public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
			throws Exception {
		System.out.println("[FirstInterceptor]afterCompletion");
	}
}

<?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:mvc="http://www.springframework.org/schema/mvc"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd
		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd">

	<!-- 自动扫描bean -->
	<context:component-scan base-package="com.hous.crud"></context:component-scan>
	<!-- 配置视图解析器 -->
	<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/views/"></property>
		<property name="suffix" value=".jsp"></property>
	</bean>
	<!-- 解决静态资源路径问题 -->
	<mvc:default-servlet-handler/>
	
	<mvc:annotation-driven conversion-service="conversionService"/>
	<!-- 
		将自定义的转换器注册到springmvc上下文中
		org.springframework.context.support.ConversionServiceFactoryBean
		org.springframework.format.support.FormattingConversionServiceFactoryBean
	 -->
	<bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
		<property name="converters">
			<set>
				<ref bean="employeeConverter"/>
			</set>
		</property>
	</bean>
	<!-- 配置国际化 -->
	<bean id="messageSource" 
		class="org.springframework.context.support.ResourceBundleMessageSource">
		<property name="basename" value="i18n"></property>
	</bean>
	<!-- 配置SessionLocaleResolver -->
	<bean id="localeResolver" 
		class="org.springframework.web.servlet.i18n.SessionLocaleResolver"></bean>
	<mvc:interceptors>
		<!-- 配置自定义拦截器 -->
		<bean class="com.hous.crud.interceptor.FirstInterceptor" />
		<!-- 配置LocaleChangeInterceptor -->
		<bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor" />
		<mvc:interceptor>
			<mvc:mapping path="/json"/>
			<bean class="com.hous.crud.interceptor.SecondInterceptor" />
		</mvc:interceptor>
	</mvc:interceptors>
	<!-- 
	<mvc:view-controller path="/i18n"/>
	 -->
	<mvc:view-controller path="/i18n2"/>
	
	<!-- 文件上传解析器 -->
	<bean id="multipartResolver"
		class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
		<property name="defaultEncoding" value="UTF-8"></property>
		<property name="maxUploadSize" value="1024000"></property>
	</bean>
	
</beans>

package com.hous.crud.interceptor;

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

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

public class SecondInterceptor implements HandlerInterceptor {

	/* 
	 * 该方法在目标方法之前被调用
	 * 若返回值为true，则继续调用后续的拦截器和目标方法
	 * 若返回值为false，则不会再调用后续的拦截器和目标方法
	 * 
	 * 可以考虑做权限，日志，事务等
	 */
	@Override
	public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception {
		System.out.println("[SecondInterceptor]preHandle");
		return true;
	}
	
	/* 
	 * 调用目标方法之后，渲染视图之前
	 * 可以对请求域中的属性或视图做出修改
	 */
	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object arg2, ModelAndView mv)
			throws Exception {
//		System.out.println(mv.getViewName());
		System.out.println(request.getRequestURI());
		System.out.println("[SecondInterceptor]postHandle");
	}

	/* 
	 * 渲染视图之后被调用，释放资源
	 */
	@Override
	public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
			throws Exception {
		System.out.println("[SecondInterceptor]afterCompletion");
	}
}