SpringMVC-Json處理-@ResponseBody（向前端頁面發送json數據）

SpringMVC-Json處理

1.前端界面發送Ajax請求：

<!--在引入文件的時候要在springmvc.xml中添加相應配置，允許訪問靜態資源-->
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-3.4.1.js"></script> 
<input type="button" value="請求json" id="btn">

<script>
    $(function(){

        $('#btn').click(function(){
          /* 發送ajax請求*/
           $.post("${pageContext.request.contextPath}/getJson",function (data) {
               console.log(data);
           });
        });

     });
</script>

2.後臺前端控制器接收請求並返回json格式的數據

 

//直接返回一個對象
@RequestMapping("getJson")
@ResponseBody/*將數據返回json格式時候需要添加這個註解*/
public User getJson(){
   //直接返回一個對象
   User user = new User();
   user.setUsername("hohh");
   user.setAge(18);
   return user;
}

//返回一個list集合
@RequestMapping("getJson")
@ResponseBody/*將數據返回json格式*/
    public  List<User> getJson(){
        User user1 = new User();
        user1.setUsername("h1");
        user1.setAge(1);
        user1.setGender(0);


        User user2 = new User();
        user2.setUsername("h2");
        user2.setAge(2);
        user2.setGender(0);

        User user3 = new User();
        user3.setUsername("h3");
        user3.setAge(3);
        user3.setGender(0);


        ArrayList<User> arrayList = new ArrayList<>();
        arrayList.add(user1);
        arrayList.add(user2);
        arrayList.add(user3);


        return arrayList;
    }
//返回一個Map集合
    @RequestMapping("getJson")
    @ResponseBody/*將數據返回json格式*/
    public  HashMap<String, Object> getJson(){
        User user1 = new User();
        user1.setUsername("h1");
        user1.setAge(1);
        user1.setGender(0);


        User user2 = new User();
        user2.setUsername("h2");
        user2.setAge(2);
        user2.setGender(0);

        User user3 = new User();
        user3.setUsername("h3");
        user3.setAge(3);
        user3.setGender(0);

        ArrayList<User> arrayList = new ArrayList<>();
        arrayList.add(user1);
        arrayList.add(user2);
        arrayList.add(user3);

        HashMap<String, Object> hashMap = new HashMap<>();
        hashMap.put("name","helong");
        hashMap.put("list",arrayList);

        return hashMap;
    }