springmvc 过滤器和拦截器

 1. 拦截器:

interceptor

过滤器(filter)与拦截器(intercepter)相同点:
1) 都可以拦截请求,过滤请求
2) 都是应用了过滤器(责任链)设计模式

2.区别:

1) filter是范围比较大,配置web.xml中

2) intercepter范围比较小,配置在springmvc中

3) 在进入springmvc处理之前,要先处理web.xml的

springmvc-servlet.txml

    <bean id="localeResolver"
           class="org.springframework.web.servlet.i18n.SessionLocaleResolver"></bean>
     <mvc:interceptors>
         <!--<bean class="com.etc.interceptor.LoginInterceptor.etc.interceptor.MyInterceptor"></bean>-->
         <bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor"></bean>
         <mvc:interceptor>
             <mvc:mapping path="/**"/>
             <mvc:exclude-mapping path="/login"/>
             <bean class="com.etc.interceptor.LoginInterceptor"/>
         </mvc:interceptor>
     </mvc:interceptors>

web.xml

     <filter>
         <filter-name>loginFilter</filter-name>
         <filter-class>com.etc.fileter.MyFileter</filter-class>
     </filter>
     <filter-mapping>
         <filter-name>loginFilter</filter-name>
         <url-pattern>/</url-pattern>
     </filter-mapping>

LoginInterceptor:

 package com.etc.interceptor;
 
 import org.springframework.web.servlet.HandlerInterceptor;
 import org.springframework.web.servlet.ModelAndView;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 
 public class LoginInterceptor implements HandlerInterceptor {
     @Override
     public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
         HttpSession session=httpServletRequest.getSession();
         if(session.getAttribute("login")==null){
             httpServletResponse.sendRedirect("/login");
             return false;
         }else {
             System.out.println("ip:"+httpServletRequest.getRemoteHost()+"url"+httpServletRequest.getRequestURL()) ;
             return true;
         }
     }
 
     @Override
     public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
 
     }
 
     @Override
     public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
 
     }
 }

MyFileter:

 package com.etc.fileter;
 
 import javax.servlet.*;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 import java.io.IOException;
 
 public class MyFileter implements Filter {
     @Override
     public void init(FilterConfig filterConfig) throws ServletException {
 
     }
 
     @Override
     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
 // 实际
         HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
         HttpServletResponse httpServletResponse = (HttpServletResponse) servletResponse;
 
         // 如果调用了这个方法,过滤器就会继承往下执行,
         HttpSession session = httpServletRequest.getSession();
         if (session.getAttribute("login") == null) {
             //没有登陆
             httpServletResponse.sendRedirect("/login");
             //return false;
         } else {
             System.out.println("ip:" + httpServletRequest.getRemoteHost() + ",url:" + httpServletRequest.getRequestURL());
             filterChain.doFilter(servletRequest, servletResponse);
             //return true;
         }
 
     }
 
     @Override
     public void destroy() {
 
     }
 }