springmvc权限拦截器

配置文件spring-servlet.xml

<?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:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="
           http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-3.0.xsd
           http://www.springframework.org/schema/mvc
           http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
    <!-- 注解扫描包 -->
    <context:component-scan base-package="com.web.controller" />  

    <!-- 开启注解 -->
    <mvc:annotation-driven/>

 	<mvc:view-controller path="/" view-name="redirect:/user/logUI" />
<!-- 	<mvc:view-controller path="/" view-name="redirect:/home/index" /> -->
    <!-- 静态资源访问 -->
    <mvc:resources location="/FlatUI/" mapping="/FlatUI/**"/>
    <mvc:resources location="/PAS_V1/" mapping="/FlatUI/**"/>
    <mvc:resources location="/img/" mapping="/img/**"/>
    <mvc:resources location="/js/" mapping="/js/**"/>
    <mvc:resources location="/css/" mapping="/css/**"/>
    <mvc:resources location="/script/" mapping="/script/**"/>
    <mvc:resources location="/style/" mapping="/style/**"/>

    <!-- ViewResolver 视图解析器 -->
    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
    <!-- 上传文件 -->
     <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
          <property name="defaultEncoding"  value="UTF-8"/>
          <property name="maxUploadSize"    value="1048576000"/>
          <property name="maxInMemorySize"  value="40960"/>
    </bean>    

    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**" />
            <bean class="com.web.controller.util.CommonInterceptor" />
        </mvc:interceptor>
    </mvc:interceptors>
	<!-- json转换器 -->
	<!--<bean id="jsonConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
		<property name="supportedMediaTypes" value="application/json" />
	</bean> -->

</beans>

拦截器源码

package com.web.controller.util;

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import com.web.controller.entity.User;

public class CommonInterceptor implements HandlerInterceptor {
	private Log log = LogFactory.getLog(this.getClass());
	@Override
	public void afterCompletion(HttpServletRequest arg0,HttpServletResponse arg1, Object arg2, Exception arg3) throws Exception {
	}

	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response,Object handler, ModelAndView modelAndView) throws Exception {
		log.info("==============执行顺序: 2、postHandle================");
	}

	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
		log.info("==============执行顺序: 1、preHandle================");
        String requestUri = request.getRequestURI();
        String contextPath = request.getContextPath();
        String url = requestUri.substring(contextPath.length());  

        log.info("requestUri:"+requestUri);
        log.info("contextPath:"+contextPath);
        log.info("url:"+url);
        //System.out.println(">>>: " + url);
        // 判断路径是登出还是登录验证，是这两者之一的话执行Controller中定义的方法
        if(url.startsWith("/user/logUI") || url.endsWith("/user/logout")) {
            return true;
        }

        // 进入登录页面，判断session中是否有key，有的话重定向到首页，否则进入登录界面
        if(url.startsWith("/user/login/")) {
            if(request.getSession() != null && request.getSession().getAttribute("usersession") != null) {
            	return true;
            }
            else {
            	response.sendRedirect("/portal/user/logUI");
            	return false;
            }
        }
        return true;
	}
}

usercontroller中的login代码

下面对用户名和密码是否为空的判断非常重要， 如果是用户已登录状态， 会造成空指针异常

@RequestMapping("/login")
	public String login(String loginName, String password, HttpSession session,HttpServletRequest request){
		//session.invalidate();
		User user = null;
		if(loginName!=null&&password!=null){
		    user = userService.findByLoginNameAndPassword(loginName, password);}

		if(user == null){
			request.setAttribute("loginError", "用户名或者密码错误");
			return "/userController/loginUI";
		}
		else{
			session.setAttribute("usersession", user);
		}
		return "/homeController/index";
	}