FastJSON

1.简介
FastJSON是一个Java语言编写的标准的JSON库，可以将Java对象转换为JSON格式，也可以将JSON字符串转换为Java对象。

2.常用方法
(1).JavaBean类

public class Student {
    private String name;
    private int age;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

	//get和set方法
}

(2).JavaBean转JSONString

public class JsonDemo {
    public static void main(String[] args) {
        List<Student> list = new ArrayList<>();
        Student steven = new Student("steven", 30);
        Student owen = new Student("owen", 28);
        list.add(steven);
        list.add(owen);
        System.out.println("*******JavaBean  to JSONString*******");
        System.out.println("*******Object*******");
        String objectStr = JSON.toJSONString(steven);
        System.out.println(objectStr);
        System.out.println("*******List*******");
        String listStr = JSON.toJSONString(list);
        System.out.println(listStr);
    }
}    

*******JavaBean  to JSONString*******
*******Object*******
{"age":30,"name":"steven"}
*******List*******
[{"age":30,"name":"steven"},{"age":28,"name":"owen"}]

(3).JSONString转JavaBean

public class JsonDemo {
    public static void main(String[] args) {
		String objectStr = "{\"age\":30,\"name\":\"steven\"}";
		String listStr = "[{\"age\":30,\"name\":\"steven\"},{\"age\":28,\"name\":\"owen\"}]";
		System.out.println("******JSONString to JavaBean*******");
		System.out.println("*******Object*******");
		Student student = JSON.parseObject(objectStr, Student.class);
		System.out.println(student);
		List<Student> studentList = JSON.parseObject(listStr,new TypeReference<List<Student>>(){});
		System.out.println(studentList);
		System.out.println();
	}
}

******JSONString to JavaBean*******
*******Object*******
Student{name='steven', age=30}
[Student{name='steven', age=30}, Student{name='owen', age=28}]

(4).JavaBean转JSONObject

public class JsonDemo {
    public static void main(String[] args) {
		System.out.println("******JavaBean to JSONObject******");
        Student steven = new Student("steven", 30);
        JSONObject stevenJsonObject = (JSONObject) JSON.toJSON(steven);
        System.out.println(stevenJsonObject.getString("name"));
        System.out.println();
    }
}

******JavaBean to JSONObject******
steven

(5).JSONObject to JavaBean

public class JsonDemo {
    public static void main(String[] args) {
		System.out.println("******JSONObject to JavaBean******");
        Student student = new Student("steven", 30);
        JSONObject stevenJsonObject= (JSONObject) JSON.toJSON(student);
        Student steven = JSON.toJavaObject(stevenJsonObject, Student.class);
        System.out.println(steven);
        System.out.println();
    }
}

******JSONObject to JavaBean******
Student{name='steven', age=30}

(6).JavaBean转JSONArray

public class JsonDemo {
    public static void main(String[] args) {
		System.out.println("*******JavaBean to JSONArray******");
        List<Student> studentList = new ArrayList<>();
        for (int i = 0; i < 5; i++) {
            studentList.add(new Student("student" + i, i));

        }
        JSONArray jsonArrays = (JSONArray) JSON.toJSON(studentList);
        for (int i = 0; i < jsonArrays.size(); i++) {
            System.out.println(jsonArrays.getJSONObject(i));
        }
        System.out.println();
    }
}

*******JavaBean to JSONArray******
{"name":"student0","age":0}
{"name":"student1","age":1}
{"name":"student2","age":2}
{"name":"student3","age":3}
{"name":"student4","age":4}