spring+ajax+spring mvc+mybatis验证用户名是否存在

js文件：

$('#name\\.info').html('');

$.ajax({
url:"/dang_ssm/user/checkName.do",
data:"name="+v,
        dataType:"text",
type:"post",
success:function(data){
     if(data=="success"){
     $('#name\\.info').html('<img src="../images/right.gif">');
    }else{
    $('#name\\.info').html('<img src="../images/wrong.gif">昵称已经被使用');
     }
}
});

控制层代码：

@Controller
@RequestMapping("/user")
public class checkEmailController {
private UserDao userDao;
public UserDao getUserDao() {
return userDao;
}
    @Resource
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
    @RequestMapping(value="/{v}.do")
    @ResponseBody
    public String checkEmail(@PathVariable("v") String v){
    List<User> list=userDao.findByEmail(v);
    if(list.isEmpty()){
    return "success";
    }
    return "error";
    }
}