json

json
        JSON(JavaScript Object Notation) 是一种轻量级的数据交换格式。它基于ECMAScript的一个子集。
    json格式:
        格式1:value可以为任意值
            {"key":value,"key1":value1}
        格式2:e可以为任意值
            [e1,e2]
    jsonlib工具类,可以使对象转换成json数据
        1.导入jar包
        2.使用api
            JSONArray.fromObject(对象)  数组和list  
            JSONObject.fromObject(对象) bean和map   

public class Demo {
    
    @Test
    //数组
    public void f1(){
        String[] arr={"aaa","bb","cc"};
        JSONArray json = JSONArray.fromObject(arr);
        System.out.println(json);
    }

["aaa","bb","cc"]

@Test
    //list
    public void f2(){
        List<String> list=new ArrayList<>();
        list.add("11");
        list.add("22");
        list.add("33");
        JSONArray json = JSONArray.fromObject(list);
        System.out.println(json);
    }

 ["11","22","33"]

@Test
    //bean
    public void f3(){
        Province pro = new Province();
        pro.setName("北京");
        pro.setProvinceid(1);
        
        JSONObject json = JSONObject.fromObject(pro);
        
        System.out.println(json);
    }

{"name":"北京","provinceid":1}

@Test
    //map
    public void f4(){
        Map<String, Object> map=new HashMap<>();
        map.put("username", "tom");
        map.put("age", 18);
        JSONObject json = JSONObject.fromObject(map);
        
        System.out.println(json);
    }

{"username":"tom","age":18}

@Test
    //bean
    public void f5(){
        List<Province> list=new ArrayList<>();
        list.add(new Province(1,"bj"));
        list.add(new Province(2,"tj"));
        list.add(new Province(3,"nj"));
        list.add(new Province(4,"dj"));
        
        
        JSONArray json = JSONArray.fromObject(list);
        
        System.out.println(json);
    }

[{"name":"bj","provinceid":1},{"name":"tj","provinceid":2},{"name":"nj","provinceid":3},{"name":"dj","provinceid":4}]

public class Province {
    private int provinceid;
    private String name;
    public int getProvinceid() {
        return provinceid;
    }
    public void setProvinceid(int provinceid) {
        this.provinceid = provinceid;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Province(int provinceid, String name) {
        super();
        this.provinceid = provinceid;
        this.name = name;
    }
    public Province() {
        super();
    
    }
    
}