servlet中实现页面跳转的两种方法1) redirect 方式

response.sendRedirect(“/a.jsp”);

页面的路径是相对路径。sendRedirect可以将页面跳转到任何页面，不一定局限于本web应用中，如：

response.sendRedirect(“URL”);

跳转后浏览器地址栏变化。

这种方式要传值出去的话，只能在url中带parameter或者放在session中，无法使用request.setAttribute来传递。

2) forward方式

RequestDispatcher dispatcher = request.getRequestDispatcher(“/a.jsp”);

dispatcher .forward(request, response);

Servlet页面跳转的路径是相对路径。forward方式只能跳转到本web应用中的页面上。

跳转后浏览器地址栏不会变化。

使用这种方式跳转，传值可以使用三种方法：url中带parameter，session，request.setAttribute

实例：

第一种方法:

AccountBean.java文件

package com.ht.servlet;

public class AccountBean {
private String username = “”;
private String password = “”;
public String getPassword() {
 return password;
}
public void setPassword(String password) {
 this.password = password;
}
public String getUsername() {
 return username;
}
public void setUsername(String username) {
 this.username = username;
}
}

CheckAccount.java文件

package com.ht.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class CheckAccount extends HttpServlet {

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
  throws ServletException, IOException {
 doGet(req,resp);
 }

@Override
public void doGet(HttpServletRequest req, HttpServletResponse resp)
  throws ServletException, IOException {
 HttpSession session = req.getSession();
 AccountBean account = new AccountBean();
 String username = req.getParameter(“username”);
 String pwd = req.getParameter(“pwd”);
 account.setPassword(pwd);
 account.setUsername(username);
 if((username != null)&&(username.trim().equals(“jsp”))) {
  if((pwd != null)&&(pwd.trim().equals(“1″))) {
   System.out.println(“success”);
   session.setAttribute(“account”, account);
   String login_suc = “success.jsp”;
    resp.sendRedirect(login_suc);
    return;
  }
 }
 String login_fail = “fail.jsp”;
 resp.sendRedirect(login_fail);
 return;
}

}

第二种方法：
package servlets;

import java.io.IOException;
import java.io.PrintWriter;

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 LoginServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {

 doPost(request,response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {

 String user = request.getParameter(“user”);
 RequestDispatcher rd = null;
  if(user!=null&&user.equals(“admin”))
 {
  request.getSession().setAttribute(“login”, “true”);
  rd = request.getRequestDispatcher(“admin.html”);
   rd.forward(request, response);  
 }
 else if(user!=null&&user.equals(“common”))
 {
  request.getSession().setAttribute(“login”, “true”);
  rd = request.getRequestDispatcher(“common.html”);
   rd.forward(request, response);    
 }
 else
  response.sendRedirect(“login.html”);
 }

}

http://blog.sina.com.cn/s/blog_5c5bc9070100zhsn.html