java web基础 --- URL重定向Filter-白红宇

java web基础 --- URL重定向Filter

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发布时间：2019-06-14

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java web基础 --- URL重定向Filter

httpRequest.getRequestDispatcher("/helloWorld").forward(httpRequest, response);

服务器端转发，不改变浏览器端URL地址，常用

httpResponse.sendRedirect(uri);

浏览器端重定向，改变URL在浏览器地址栏

URLOverWriteFilter.java

1 package com.web1.util; 2  3 import java.io.IOException; 4  5 import javax.print.attribute.standard.ReferenceUriSchemesSupported; 6 import javax.servlet.Filter; 7 import javax.servlet.FilterChain; 8 import javax.servlet.FilterConfig; 9 import javax.servlet.ServletException;10 import javax.servlet.ServletRequest;11 import javax.servlet.ServletResponse;12 import javax.servlet.annotation.WebFilter;13 import javax.servlet.http.HttpServletRequest;14 import javax.servlet.http.HttpServletResponse;15 16 /**17  * Servlet Filter implementation class URLOverWriteFilter18  */19 @WebFilter("/URLOverWriteFilter")20 public class URLOverWriteFilter implements Filter {21 22     private FilterConfig config;23     /**24      * Default constructor. 25      */26     public URLOverWriteFilter() {27         // TODO Auto-generated constructor stub28     }29 30     /**31      * @see Filter#destroy()32      */33     public void destroy() {34         // TODO Auto-generated method stub35     }36 37     /**38      * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)39      */40     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {41         //do something42         String uri = "";43         HttpServletRequest httpRequest = null;44         if (request instanceof HttpServletRequest) {45             httpRequest = (HttpServletRequest)request;46             System.out.println("URL:" + httpRequest.getRequestURL().toString());47             System.out.println("URI:" + httpRequest.getRequestURI().toString());48             uri = httpRequest.getRequestURI();49             uri = uri.replace("home.html", "helloWorld");50         }51         if (httpRequest.getRequestURI().indexOf("home.html") >= 0) {52             /*if (response instanceof HttpServletResponse) {53                 HttpServletResponse httpResponse = (HttpServletResponse)response;54                 httpResponse.sendRedirect(uri);55             }*/56             httpRequest.getRequestDispatcher("/helloWorld").forward(httpRequest, response);57         }58         else{59             //go to next Filter60             chain.doFilter(request, response);61         }62     }63 64     /**65      * @see Filter#init(FilterConfig)66      */67     public void init(FilterConfig fConfig) throws ServletException {68         this.config = fConfig;69     }70 71 }

web.xml

按照filter-mapping的顺序


     
       
      
                Hello World Servlet    
        
      
       Hello World Servlet
        
          
       
        Encode Filter
           
       
        com.web1.util.RequestEncodeFilter
         
        
          
       
        Encode Filter
           
       
        /*
         
          
          
       
        URLOverFilter Filter
           
       
        com.web1.util.URLOverWriteFilter
         
        
          
       
        URLOverFilter Filter
           
       
        /home.html
         
          
          
       
        helloWorld
           
       
        com.web1.hello.HelloWorldServlet
         
        
          
       
        helloWorld
           
       
        /helloWorld
         
        
          
       
        helloImage
           
       
        com.web1.hello.ImageServlet
         
        
          
       
        helloImage
           
       
        /helloImage