package joanna.yan.ssm.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 HandlerInterceptor1 implements HandlerInterceptor{//执行Handler完成执行此方法//应用场景：统一异常处理，统一日志处理
    @Overridepublic void afterCompletion(HttpServletRequest request,HttpServletResponse response, Object handler, Exception ex)throws Exception {System.out.println("HandlerInterceptor1......afterCompletion");}//进入Handler方法之后，返回modelAndView之前执行//应用场景从modelAndView出发：将公用的模型数据（比如菜单导航）在这里传到视图，也可以在这里同意指定视图
    @Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response,Object handler, ModelAndView modelAndView) throws Exception {System.out.println("HandlerInterceptor1......postHandle");}//进入Handler方法之前执行//用于身份认证、身份授权//比如身份认证，如果认证不通过表示当前用户没有登录，需要此方法拦截不再向下执行。
    @Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws Exception {System.out.println("HandlerInterceptor1......preHandle");//return false表示拦截，不向下执行//return true表示放行return true;}}

<beanclass="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"><property name="interceptors"><list><ref bean="handlerInterceptor1"/><ref bean="handlerInterceptor2"/></list></property>
</bean><bean id="handlerInterceptor1" class="joanna.yan.ssm.interceptor.HandlerInterceptor1"/><bean id="handlerInterceptor2" class="joanna.yan.ssm.interceptor.HandlerInterceptor2"/>

    <!--拦截器 --><mvc:interceptors><!--多个拦截器,顺序执行 --><mvc:interceptor><!-- /**表示所有url包括子url路径 --><mvc:mapping path="/**"/><bean class="joanna.yan.ssm.interceptor.HandlerInterceptor1"></bean></mvc:interceptor><mvc:interceptor><mvc:mapping path="/**"/><bean class="joanna.yan.ssm.interceptor.HandlerInterceptor2"></bean></mvc:interceptor></mvc:interceptors>

HandlerInterceptor1...preHandle
HandlerInterceptor2...preHandleHandlerInterceptor2...postHandle
HandlerInterceptor1...postHandleHandlerInterceptor2...afterCompletion
HandlerInterceptor1...afterCompletion

HandlerInterceptor1...preHandle
HandlerInterceptor2...preHandle
HandlerInterceptor1...afterCompletion

HandlerInterceptor1...preHandle

package joanna.yan.ssm.controller;import javax.servlet.http.HttpSession;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;@Controller
public class LoginController {//登录@RequestMapping("/login")public String login(HttpSession session, String username, String password) throws Exception{//调用service进行用户身份认证//...//在session中保存用户身份信息session.setAttribute("username", username);return "redirect:items/queryItems.action";}//退出@RequestMapping("/logout")public String logout(HttpSession session) throws Exception{//清除session
        session.invalidate();return "redirect:items/queryItems.action";}}

public class LoginInterceptor implements HandlerInterceptor{//执行Handler完成执行此方法//应用场景：统一异常处理，统一日志处理
    @Overridepublic void afterCompletion(HttpServletRequest request,HttpServletResponse response, Object handler, Exception ex)throws Exception {System.out.println("HandlerInterceptor1......afterCompletion");}//进入Handler方法之后，返回modelAndView之前执行//应用场景从modelAndView出发：将公用的模型数据（比如菜单导航）在这里传到视图，也可以在这里同意指定视图
    @Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response,Object handler, ModelAndView modelAndView) throws Exception {System.out.println("HandlerInterceptor1......postHandle");}//进入Handler方法之前执行//用于身份认证、身份授权//比如身份认证，如果认证不通过表示当前用户没有登录，需要此方法拦截不再向下执行。
    @Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws Exception {System.out.println("HandlerInterceptor1......preHandle");//获取请求的urlString url=request.getRequestURI();//判断url是否是公开地址（实际使用时要将公开地址配置到文件中）//这里公开地址是登录提交的地址if(url.indexOf("login.action")>=0){//如果进行登录提交，放行return true;}//判断sessionHttpSession session=request.getSession();String username=(String) session.getAttribute("username");if(username!=null){//身份存在，放行return true;}//执行到这里，表示用户身份需要认证，跳转登录页面request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);//return false表示拦截，不向下执行//return true表示放行return false;}}