struts2+jquery实现ajax登陆实例详解

package com.action;

import org.apache.struts2.convention.annotation.Action;
import org.apache.struts2.convention.annotation.ParentPackage;
import org.apache.struts2.convention.annotation.Result;
import org.apache.struts2.convention.annotation.Results;

import com.opensymphony.xwork2.ActionSupport;

@Action("login")
@ParentPackage(value = "json-default")
@Results({ @Result(name = "success", type = "json", params = { "data", "flag" }), })
public class LoginAction extends ActionSupport {

  /**
   * 
   */
  private static final long serialVersionUID = 1751244794407005783L;
  private String flag;
  private String username;
  private String password;

  public String execute() {
    try {
      if (getUsername() == null || getUsername().trim().equals("")) {
        setFlag("用户名不能为空");
        return SUCCESS;
      } else if (getPassword() == null || getPassword().trim().equals("")) {
        setFlag("密码不能为空");
        return SUCCESS;
      } else if (getUsername().trim().equals("admin")
           getPassword().equals("admin")) {
        setFlag("登陆成功");
        return SUCCESS;
      } else {
        setFlag("用户名或密码错误");
        return SUCCESS;
      }
    } catch (Exception e) {
      e.printStackTrace();
      setFlag("登陆异常");
      return SUCCESS;
    }
  }

  public String getFlag() {
    return flag;
  }

  public void setFlag(String flag) {
    this.flag = flag;
  }

  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;
  }

}

%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
%
  String path = request.getContextPath();
  String basePath = request.getScheme() + "://"
      + request.getServerName() + ":" + request.getServerPort()
      + path + "/";
%>

!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
html>
head>
base href="%=basePath%>" rel="external nofollow" >

title>My JSP 'index.jsp' starting page/title>
meta http-equiv="pragma" content="no-cache">
meta http-equiv="cache-control" content="no-cache">
meta http-equiv="expires" content="0">
meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
meta http-equiv="description" content="This is my page">
script type="text/javascript" src="./resource/js/jquery.min.js">/script>
/head>
script type="text/javascript">
  $(document).ready(function() {
    $(".loginButton").click(function() {
      var name = $("#username").val();//获取登陆用户名
      var password = $("#password").val(); //获取登陆密码
      $.post("login", {
        username : name,
        password : password
      }, callback, "json");
    });

    function callback(data) {
      var value=data.flag;
      if(value=="登陆成功"){
      location.href="./success.jsp" rel="external nofollow" ;
      }else{
       alert(value);
    }
  });
/script>
body>
  input name="username" id="username" type="text" />
  input name="password" id="password" type="password" />
  button class="loginButton" class="btn btn-inverse">登陆/button>
/body>
/html>