使用getNamedDispatcher()转发请求

来源：互联网发布：python 爬虫伯乐在线编辑：程序博客网时间：2024/06/05 14:22

请注意web.xml

<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">  <display-name>servletNamedDispatcher</display-name>   <servlet>    <servlet-name>Controller</servlet-name>      <servlet-class>liuliking.Controller</servlet-class>    </servlet>    <servlet>     <servlet-name>Weather</servlet-name>        <servlet-class>liuliking.Weather</servlet-class>    </servlet>        <servlet-mapping>        <servlet-name>Controller</servlet-name>        <url-pattern>/controller</url-pattern>    </servlet-mapping>    <welcome-file-list>    <welcome-file>index.html</welcome-file>     </welcome-file-list></web-app>

这里，对于liuliking.Weather这个servlet，并没有下面对应的条目：

<servlet-mapping>        <servlet-name>Weather</servlet-name>        <url-pattern>/weather</url-pattern>    </servlet-mapping>

但这并不影响转发

package liuliking;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.*;import javax.servlet.http.*;public class Weather extends HttpServlet{public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException{PrintWriter out = response.getWriter();System.out.println("这里");out.println();out.println("<html><body>");out.println("<h2>This is Weather Servlet</h2>");out.println("</html></body>");}}

package liuliking;import java.io.IOException;import javax.servlet.*;import javax.servlet.http.*;import javax.servlet.ServletException;public class Controller extends HttpServlet{public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException,ServletException{RequestDispatcher dispatcher = null;String param = request.getParameter("go");if(param.equals("weather")){dispatcher = getServletContext().getNamedDispatcher("Weather");}if(dispatcher != null){dispatcher.forward(request,response);}}}

源代码：http://pan.baidu.com/share/link?shareid=4144844182&uk=3878681452