Servlet跳转
1、客户端跳转
在Servlet中如果要想进行客户端跳转，直接使用HttpServletResponse接口的sendRedirect()方法即可，要注意的是：此跳转只能传递session范围的属性，无法传递request范围属性。
客户端跳转————ClientRedirect.java
package com.ls.servlet_04;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ClientRedirect extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.getSession().setAttribute("name", "刘胜");
request.setAttribute("info", "Java Web");
response.sendRedirect("get_info.jsp");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doGet(request, response);
}
}
配置web.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>ClientRedirect</servlet-name>
<servlet-class>com.ls.servlet_04.ClientRedirect</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ClientRedirect</servlet-name>
<url-pattern>/servlet_ClientRedirect</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
接收属性————get_info.jsp
<?xml version="1.0" encoding="UTF-8" ?>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>getInfo</title>
</head>
<%request.setCharacterEncoding("GBK"); %>
<body>
<h2>session属性：<%=session.getAttribute("name") %></h2>
<h2>request属性：<%=request.getAttribute("info") %></h2>
</body>
</html>
在地址栏输入“http://localhost:8080/servletdemo/servlet_ClientRedirect”（servletdemo根据自己的Myeclipse创建的工程名而定）
运行结果：
由于是客户端跳转，从运行程序结果可以发现，跳转后的地址栏是会发生变化的，只能接收session属性范围的内容，不能接收request属性范围的内容
2、服务器跳转
在Servlet中没有像JSP中<jsp:forward>指令，要想执行服务器跳转就必须依靠RequestDispatcher接口完成，此接口有两种方法：
public void forward （ServletRequest request, ServletResponse response）throws ServletException，IOException 页面跳转
public void include（ServletRequest request, ServletResponse response）throws ServletException，IOException 页面包含
使用RequestDispatcher接口的forward（）方法即可完成跳转功能的实现，但是如果要想使用此接口需要使用ServletRequest接口提供的方法实例化：
public RequestDispatcher getRequestDispatcher（String path） 取得RequestDispatcher接口实例
使用服务器跳转————ServerRedirect.java
package com.ls.servlet_05;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ServerRedirect extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.getSession().setAttribute("name", "刘胜");
request.setAttribute("info", "Java Web");
RequestDispatcher rd=request.getRequestDispatcher("get_info.jsp");
rd.forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doGet(request, response);
}
}
配置web.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>ServerRedirect</servlet-name>
<servlet-class>com.ls.servlet_05.ServerRedirect</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ServerRedirect</servlet-name>
<url-pattern>/servlet_ServerRedirect</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
接收属性————get_info.jsp
<?xml version="1.0" encoding="UTF-8" ?>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>getInfo</title>
</head>
<%request.setCharacterEncoding("GBK"); %>
<body>
<h2>session属性：<%=session.getAttribute("name") %></h2>
<h2>request属性：<%=request.getAttribute("info") %></h2>
</body>
</html>
在地址栏输入“http://localhost:8080/servletdemo/servlet_ServerRedirect”（servletdemo根据自己的Myeclipse创建的工程名而定）
运行结果：
服务器跳转后，地址栏不发生变化，而且此时尅在跳转后的JSP文件中接收到session及request范围的属性