使用ajax实现登录功能

前端ajax登录代码：

  //测试提交，对接程序删除即可
  $("#login").click(function(){
      var thisUsername = document.getElementById("username").value;
      var thisPassword = document.getElementById("password").value;
      
      if(username != null){
          if(password != null){
              // 第一个参数是提交的地址
              $.post("http://localhost:8080/login.do",
                {
                    // 提交时携带的参数
                    username:thisUsername,
                    password:thisPassword
                },
                // 回调函数,data是服务器返回的数据
                function(data,status){
                    var dataObj=eval("("+data+")");//转换为json对象 
                    
                    // dataObj.code是服务器返回的一个数据
                    if(dataObj.code == 1){
                        location.href="main.html";
                    }else{
                        alert(dataObj.msg)
                        return;
                    }
                });
            }
        }
      });

后台对请求进行处理：

package com.kude.controller;

import com.kude.pojo.User;
import com.kude.service.UserService;
import com.kude.util.ImgFormat;
import net.sf.json.JSONObject;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.List;

/**
 * @Author: 樊小铭
 * 登录功能
 * @Date: 2019/7/13 9:32
 */

@Controller
@ResponseBody
public class LoginController {

    @Autowired
    private UserService userService;

    @RequestMapping(value = "/login.do",produces = "text/plain;charset=utf-8")
    public String login(String username, String password, HttpServletRequest request, HttpServletResponse response){

        response.setCharacterEncoding("utf-8");

        User u =  userService.selectByUsername(username);

        ImgFormat message = new ImgFormat();

        // 通过用户名来匹配登录的用户信息
        
            if(u.getUsername().equals(username)){
                if(u.getPassword().equals(password)){

                    // 将用户信息保存到session中
                    HttpSession session = request.getSession();
                    session.setAttribute("user",u);

                    // 返回一个json格式的数据
                    message.setCode(1);
                    message.setMsg("登陆成功");
                    message.setData(JSONObject.fromObject(u));
                    return JSONObject.fromObject(message).toString();
                }
                message.setCode(0);
                message.setMsg("密码不正确");
                return JSONObject.fromObject(message).toString();
            }
            message.setCode(0);
            message.setMsg("账号不存在");
            return JSONObject.fromObject(message).toString();
        }
        message.setCode(0);
        message.setMsg("请登录账户");
        return JSONObject.fromObject(message).toString();
    

}