JSONObject只是一种数据结构，可以理解为JSON格式的数据结构（key-value 结构），可以使用put方法给json对象添加元素。JSONObject可以很方便的转换成字符串，也可以很方便的把其他对象转换成JSONObject对象。

pom：

 <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.28</version>
        </dependency>

1.通过原生生成json数据格式。

JSONObject zhangsan = new JSONObject();
        try {
            //添加
            zhangsan.put("name", "张三");
            zhangsan.put("age", 18.4);
            zhangsan.put("birthday", "1900-20-03");
            zhangsan.put("majar", new String[] {"哈哈","嘿嘿"});
            zhangsan.put("null", null);
            zhangsan.put("house", false);
            System.out.println(zhangsan.toString());
        } catch (JSONException e) {
            e.printStackTrace();
        }

2.通过hashMap数据结构生成

     HashMap<String, Object> zhangsan = new HashMap<>();
        
        zhangsan.put("name", "张三");
        zhangsan.put("age", 18.4);
        zhangsan.put("birthday", "1900-20-03");
        zhangsan.put("majar", new String[] {"哈哈","嘿嘿"});
        zhangsan.put("null", null);
        zhangsan.put("house", false);
        System.out.println(new JSONObject(zhangsan).toString());

3.通过实体生成 

        Student student = new Student();
        student.setId(1);
        student.setAge("20");
        student.setName("张三");
        //生成json格式
        System.out.println(JSON.toJSON(student));
        //对象转成string
        String stuString = JSONObject.toJSONString(student);

4.JSON字符串转换成JSON对象

String studentString = "{\"id\":1,\"age\":2,\"name\":\"zhang\"}";

//JSON字符串转换成JSON对象
JSONObject jsonObject1 = JSONObject.parseObject(stuString);

System.out.println(jsonObject1);

5.list对象转listJson

ArrayList<Student> studentLsit = new ArrayList<>();
        Student student1 = new Student();
        student1.setId(1);
        student1.setAge("20");
        student1.setName("asdasdasd");

        studentLsit.add(student1);

        Student student2 = new Student();
        student2.setId(2);
        student2.setAge("20");
        student2.setName("aaaa:;aaa");

        studentLsit.add(student2);

        //list转json字符串
        String string = JSON.toJSON(studentLsit).toString();
        System.out.println(string);

        //json字符串转listJson格式
        JSONArray jsonArray = JSONObject.parseArray(string);

        System.out.println(jsonArray);

 

 

阿里的json很好用，还有一个谷歌Gson也不错。有兴趣的可以看一看

JSONObject jo= (JSONObject) JSONObject.toJSON(javaBean); 

Student stu = JSONObject.parseObject(jo, Student.class);

JSONObject jo = JSON.parseObject(str);

 

JSONObject jsonObject = JSONObject.fromObject(result);报错

引用import net.sf.json.JSONObject;
 <!-- JSONObject对象依赖的jar包 -->
        <dependency>
            <groupId>commons-beanutils</groupId>
            <artifactId>commons-beanutils</artifactId>
            <version>1.9.3</version>
        </dependency>
		 <dependency>
            <groupId>commons-collections</groupId>
            <artifactId>commons-collections</artifactId>
            <version>3.2.1</version>
        </dependency>
		<dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.1.1</version>
        </dependency>
        <dependency>
            <groupId>net.sf.ezmorph</groupId>
            <artifactId>ezmorph</artifactId>
            <version>1.0.6</version>
        </dependency>
         <dependency>
			<groupId>net.sf.json-lib</groupId>
			<artifactId>json-lib</artifactId>
			<version>2.2.3</version>
			<classifier>jdk15</classifier><!-- 指定jdk版本 -->
		</dependency>

目录

1、JSONObject 和String 之间的转化

2、JSONObject 和 bean  之间的转化

3、JSONObject 和 list 之间的转化

4、JSONObject 和 array之间的转化

5、复杂json 用JSONObject 转换

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Employee {

    private String name;
    private Integer age;
    private BigDecimal salary;
    private String height;
}

    public static void main(String[] args) {

        List<Employee> employees = Arrays.asList(

                new Employee("张三", 18, new BigDecimal("9999"),"180"),
                new Employee("李四", 18, new BigDecimal("8888"),"180"),
                new Employee("翠花", 18, new BigDecimal("7777"),"180")

        );

        Employee employee = new Employee();
        employee.setAge(18);
        employee.setName("test");
        String s = JSONObject.toJSONString(employee);
        System.out.println("JSONObject 和String 之间的转化>>>" + s);

        String str = "{\"age\":18,\"name\":\"test\",\"salary\":20}";
        Employee employee1 = JSONObject.toJavaObject(JSONObject.parseObject(str), Employee.class);
        System.out.println("JSONObject 和 bean  之间的转化>>>" + employee1);

        String str1 = JSONObject.toJSONString(employees);
        System.out.println("JSONObject 和 list 之间的转化>>>" + str1);