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

package com.web1.util;

import java.io.IOException;

import javax.print.attribute.standard.ReferenceUriSchemesSupported;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* Servlet Filter implementation class URLOverWriteFilter
*/
@WebFilter("/URLOverWriteFilter")
public class URLOverWriteFilter implements Filter {

private FilterConfig config;
/**
* Default constructor.
*/
public URLOverWriteFilter() {
// TODO Auto-generated constructor stub
}

/**
* @see Filter#destroy()
*/
public void destroy() {
// TODO Auto-generated method stub
}

/**
* @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
*/
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
//do something
String uri = "";
HttpServletRequest httpRequest = null;
if (request instanceof HttpServletRequest) {
httpRequest = (HttpServletRequest)request;
System.out.println("URL:" + httpRequest.getRequestURL().toString());
System.out.println("URI:" + httpRequest.getRequestURI().toString());
uri = httpRequest.getRequestURI();
uri = uri.replace("home.html", "helloWorld");
}
if (httpRequest.getRequestURI().indexOf("home.html") >= 0) {
/*if (response instanceof HttpServletResponse) {
HttpServletResponse httpResponse = (HttpServletResponse)response;
httpResponse.sendRedirect(uri);
}*/
httpRequest.getRequestDispatcher("/helloWorld").forward(httpRequest, response);
}
else{
//go to next Filter
chain.doFilter(request, response);
}
}

/**
* @see Filter#init(FilterConfig)
*/
public void init(FilterConfig fConfig) throws ServletException {
this.config = fConfig;
}

}


web.xml

按照filter-mapping的顺序

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" metadata-complete="true" version="3.0">
<description>
Hello World Servlet
</description>
<display-name>Hello World Servlet</display-name>
<filter>
<filter-name>Encode Filter</filter-name>
<filter-class>com.web1.util.RequestEncodeFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>Encode Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

<filter>
<filter-name>URLOverFilter Filter</filter-name>
<filter-class>com.web1.util.URLOverWriteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>URLOverFilter Filter</filter-name>
<url-pattern>/home.html</url-pattern>
</filter-mapping>

<servlet>
<servlet-name>helloWorld</servlet-name>
<servlet-class>com.web1.hello.HelloWorldServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>helloWorld</servlet-name>
<url-pattern>/helloWorld</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>helloImage</servlet-name>
<servlet-class>com.web1.hello.ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>helloImage</servlet-name>
<url-pattern>/helloImage</url-pattern>
</servlet-mapping>
</web-app>