1.我这里使用的是阿里的fastjson的jar包

 <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.53</version>
        </dependency>

2.我们先生成一个Student类

package com.it.model;


public class Student {
    private String name;
    private int age;
    private String sex;
    private double score;

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

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder("Student{");
        sb.append("name='").append(name).append('\'');
        sb.append(", age=").append(age);
        sb.append(", sex='").append(sex).append('\'');
        sb.append(", score=").append(score);
        sb.append('}');
        return sb.toString();
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public double getScore() {
        return score;
    }
    public void setScore(double score) {
        this.score = score;
    }
}

2.我们先来进行对象转换成json

下面是我们的测试代码

 @Test
    public void testObj2Json(){
        Student student = new Student("wen",23,"男",98.5);
        String s = JSONObject.toJSONString(student);
        System.out.println(s);
    }

测试结果如下:

{"age":23,"name":"wen","score":98.5,"sex":"男"}

3.json转换成对象

@Test
    public void testJson2Object(){
        String str = "{\"age\":23,\"name\":\"wen\",\"score\":98.5,\"sex\":\"男\"}";
        Student student = JSONObject.parseObject(str, Student.class);
        System.out.println(student);
    }

测试结果如下:

Student{name='wen', age=23, sex='男', score=98.5}

4.array转换成json

 @Test
    public void testArray2Json(){
        ArrayList<Student> students = new ArrayList<>();
        for (int i = 1; i < 5; i++) {
            Student student = new Student("wen"+i,23+i,"男",98.5-i);
            students.add(student);
        }
        String s = JSONObject.toJSONString(students);
        System.out.println(s);
    }

测试结果如下:

[{"age":24,"name":"wen1","score":97.5,"sex":"男"},{"age":25,"name":"wen2","score":96.5,"sex":"男"},{"age":26,"name":"wen3","score":95.5,"sex":"男"},{"age":27,"name":"wen4","score":94.5,"sex":"男"}]

5.json转换成array

 @Test
    public void testJson2Array(){
        String str = "[{\"age\":24,\"name\":\"wen1\",\"score\":97.5,\"sex\":\"男\"},{\"age\":25,\"name\":\"wen2\",\"score\":96.5,\"sex\":\"男\"},{\"age\":26,\"name\":\"wen3\",\"score\":95.5,\"sex\":\"男\"},{\"age\":27,\"name\":\"wen4\",\"score\":94.5,\"sex\":\"男\"}]";
        List<Student> students = JSONObject.parseArray(str, Student.class);
        for (Student student : students) {
            System.out.println(student);
        }
    }

测试结果如下:

Student{name='wen1', age=24, sex='男', score=97.5}
Student{name='wen2', age=25, sex='男', score=96.5}
Student{name='wen3', age=26, sex='男', score=95.5}
Student{name='wen4', age=27, sex='男', score=94.5}

从这里可以看出来,fastjson使用比原的json好用多了,这我们可以自己写一个工具类方便我们以后来使用.