JSON

        JSON（JavaScript Object Notation）翻译为JavaScript对象，这是JS语言的对象表示形式，常用项目前后端之间的信息交互

* java对象表示形式
    User user = new User();
    user.setUsername("后羿");
    user.setAge(23);
    user.setSex("男");
			
* javaScript对象(JSON)表示形式
    {
        "username":"后羿",
        "age":"23",
        "sex":"男",
    }

Java对象转换JOSN对象

导入Josn坐标

 

    com.fasterxml.jackson.core
    jackson-core
    2.9.0


    com.fasterxml.jackson.core
    jackson-databind
    2.9.0


    com.fasterxml.jackson.core
    jackson-annotations
    2.9.0

package com.itheima.test;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.itheima.domain.User;
import lombok.ToString;
import org.junit.Test;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


public class JsonTransferTest {

    
    @Test
    public void testDomain()throws Exception{
        User user = new User(1,"隔壁老王","男","北京","test@itcast.cn");
        //1.创建转换对象
        ObjectMapper objectMapper = new ObjectMapper();
        String json = objectMapper.writeValueAsString(user);
        System.out.println(json);
    }

    
    @Test
    public void testList()throws Exception{
        User u1 = new User(1,"隔壁老王1","男","北京","test@itcast.cn");
        User u2 = new User(2,"隔壁老王2","男","北京","test@itcast.cn");
        User u3 = new User(3,"隔壁老王3","男","北京","test@itcast.cn");

        List users = new ArrayList<>();
        users.add(u1);
        users.add(u2);
        users.add(u3);

        ObjectMapper objectMapper = new ObjectMapper();
        String json = objectMapper.writeValueAsString(users);
        System.out.println(json);
    }


    
    @Test
    public void testMap()throws Exception{
        User u1 = new User(1,"隔壁老王1","男","北京","test@itcast.cn");
        User u2 = new User(2,"隔壁老王2","男","北京","test@itcast.cn");
        User u3 = new User(3,"隔壁老王3","男","北京","test@itcast.cn");

        Map map = new HashMap<>();
        map.put("u1",u1);
        map.put("u2",u2);
        map.put("u3",u3);

        ObjectMapper objectMapper = new ObjectMapper();
        String json = objectMapper.writeValueAsString(map);
        System.out.println(json);
    }
}

JOSN转Java对象

    
    @Test
    public void testJsonToDomain()throws Exception{
        String json = "{"id":1,"name":"隔壁老王1","gender":"男","address":"北京","email":"test@itcast.cn"}";
        ObjectMapper objectMapper = new ObjectMapper();
        User user = objectMapper.readValue(json, User.class);
        System.out.println(user);
    }

 AJAX

        AJAX(Asynchronous JavaScript and XML)异步的 JavaScript 和 XML

发送get请求：
axios.get(请求的地址?请求的参数).then(function(参数){
});


发送post请求：
axios.post(请求的地址,请求的参数).then(function(参数){
});

    
    
    
    
    
    


测试异步交互