S2SH整合JQuery+Ajax实现登录验证的代码

package com.lk.action;
import javax.annotation.Resource;
import com.googlecode.jsonplugin.annotations.JSON;
import com.lk.service.StudentControl;
import com.opensymphony.xwork2.ActionSupport;
public class LoginAjaxAction extends ActionSupport {
private String username;
private StudentControl studentControl;
@JSON(serialize=false) //setStudentControl利用了spring，很重要，让studentControl不序列化,如果序列化会报错
public StudentControl getStudentControl() {//这个错，找了好久...ajax一直返回error
return studentControl;
}
@Resource(name="studentControl")
public void setStudentControl(StudentControl studentControl) {
this.studentControl = studentControl;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
@Override
public String execute() throws Exception {
if(studentControl.getStudentById(Integer.parseInt(username))!=null){
username = "用户存在";
}else{
username = "用户不存在";
}

return "success";
}
}

<package name="ajax" extends="json-default">
<action name="loginAjax" class="com.lk.action.LoginAjaxAction">
<result type="json" />
</action>
</package>

//用户名 绑定的事件 焦点的移入和移出
$("#un").bind({
focus:function(){
$(this).addClass("txtclick");
},
blur:function(){
var vtxt = $("#un").val();
if (vtxt.length == 0) {
$("#unerror").html("用户名不能为空");
$(this).removeClass("txtclick");
}else if(!isInteger(vtxt)){
//检测用户名格式是否正确
$("#unerror").html("格式不正确！");
$(this).removeClass("txtclick");
}else{
$.ajax({
url : "loginAjax",
dataType : "json",
data : {
username : $(this).val(),
time : Math.random()*1000
},
success : function(data){
alert("成功"+data.username);
},
error : function(){
alert("错误");
}
})
}
}
});