javaee SpringMVC中json的使用

jsp

<%--Created by IntelliJ IDEA.User: 呆萌老师:QQ:2398779723Date: 2019/12/6Time: 15:55To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%String baseurl=request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+request.getContextPath();pageContext.setAttribute("baseurl",baseurl);
%>
<html>
<base href="${baseurl}" />
<head><title>Title</title><script src="${baseurl}/static/js/jquery1.11.3.min.js"></script><script src="${baseurl}/static/js/reg.js"></script>
</head>
<body>
<from action="${baseurl}/users/reg" method="post"><pre>用户名:<input type="text" name="uname" /><span id="s1"></span>密码:<input type="password" name="pwd" />确认密码:<input type="password" name="repwd" />专业:<select id="major" ></select><input type="submit" name="sub" value="注册" /></pre>
</from>
</body>
</html>

js


$(function(){//给文本框做失去焦点事件$(":text[name='uname']").blur(function(){//1.获得用户名var uname=$(this).val();//2.通过ajax将用户名传到服务器端 判断 将结果返回$.get("http://localhost:8080/TestSpringMVC4/users/checkUname?uname="+uname,function(msg){//3.处理返回的结果if(msg=="exists")$("#s1").html("已存在");else$("#s1").html("可以使用");})})//加载所有的专业信息$("#major").click(function(){//通过ajax到服务器端取回所有的专业信息$.getJSON("http://localhost:8080/TestSpringMVC4/users/getMajorList2",function(arr){//清除之前的option$("#major").empty();$.each(arr,function(k,v){//返回的数据 组装成option添加到select中var option=$("<option></option>");option.val(v.id);option.html(v.name);$("#major").append(option);})})})})

java

package com.test.controller;import com.alibaba.fastjson.JSON;
import com.test.pojo.Major;
import com.test.pojo.Users;
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.HttpSession;
import java.util.ArrayList;
import java.util.List;@Controller
@RequestMapping("/users")
public class UsersController {@RequestMapping("/loginUi")public String loginUi(){return "login";}@RequestMapping("/checkLogin")public String checkLogin(Users user, HttpServletRequest request){if(user.getUname().equals("daimenglaoshi") && user.getPwd().equals("123")){//存入sessionHttpSession session= request.getSession();session.setAttribute("loginUser",user);//重定向return "redirect:/index.jsp";}elsereturn "login";}@RequestMapping("/regUi")public String regUi(){return "reg";}@RequestMapping("/checkUname")//返回响应体(响应的内容)  不做转发@ResponseBodypublic String checkUname(String uname){if(uname.equals("daimenglaoshi"))return "exists";elsereturn "not exists";}@RequestMapping("/getMajorList")@ResponseBody//框架会帮你转换成json字符串的public List<Major> getMajorList(){List<Major> majorList=new ArrayList<Major>();System.out.println("2222");majorList.add(new Major(1,"aaa"));majorList.add(new Major(2,"bb"));return majorList;}@RequestMapping(value="/getMajorList2",produces = "text/html;charset=utf-8")@ResponseBodypublic String getMajorList2(){List<Major> majorList=new ArrayList<Major>();majorList.add(new Major(1,"计算机"));majorList.add(new Major(2,"英语"));return JSON.toJSONString(majorList);}}