java 解析json中的数组对象数组 java的json解析几种方法

我们在日常开发中少不了和JSON数据打交道，那么我们来看看JAVA中常用的JSON解析方式。 
1、JSON官方 
2、GSON 
3、FastJSON 
4、jackson 

JSON操作涉及到的类：

 

 

public class Student {

    private int id;
    private String name;
    private int age;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    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 Student(int id, String name, int age) {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
    }
    public Student() {
        super();
    }
    @Override
    public String toString() {
        return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";
    }
}

 

 

public class Grade {

    private int id;
    private String name;
    private ArrayList<Student> stus;
    public Grade(int id, String name, ArrayList<Student> stus) {
        super();
        this.id = id;
        this.name = name;
        this.stus = stus;
    }
    public Grade() {
        super();
    }
    @Override
    public String toString() {
        return "Grade [id=" + id + ", name=" + name + ", stus=" + stus + "]";
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public ArrayList<Student> getStus() {
        return stus;
    }
    public void setStus(ArrayList<Student> stus) {
        this.stus = stus;
    }

}

 

（1）JSON官方的解析

 

public class JSONTest {

//解析JSON
    @Test
    public void test1() throws JSONException{
        //对象嵌套数组嵌套对象
        String json1="{'id':1,'name':'JAVAEE-1703','stus':[{'id':101,'name':'刘一','age':16}]}";
        //数组
        String json2="['北京','天津','杭州']";

        //1、
        //解析第一层---对象
        JSONObject jObject1=new JSONObject(json1);
        Grade grade=new Grade();
        grade.setId(jObject1.getInt("id"));
        grade.setName(jObject1.getString("name"));
        ArrayList<Student> stus=new ArrayList<>();
        grade.setStus(stus);
        //解析第二层----数组
        JSONArray jsonArray2=jObject1.getJSONArray("stus");
        //遍历数组获取元素----对象
        for(int i=0;i<jsonArray2.length();i++){
            //解析第三层----对象
            JSONObject jObject3=jsonArray2.getJSONObject(i);
            Student student=new Student(jObject3.getInt("id"), jObject3.getString("name"), jObject3.getInt("age"));
            grade.getStus().add(student);
        }

        System.out.println(grade);

       
        //2、
        //获取数组对象
        JSONArray jArray=new JSONArray(json2);
        ArrayList<String> list=new ArrayList<>();
        //遍历获取元素
        for(int i=0;i<jArray.length();i++){
            //jArray.optString(i);//等价于getXXX
            list.add(jArray.getString(i));
        }
        System.out.println("解析结果："+list);
    }

//生成JSON
    @Test
    public void test2() throws JSONException{
        JSONObject jo1=new JSONObject();
        jo1.put("id", 1001);
        jo1.put("name", "范老");
        jo1.put("age", 20);
        JSONObject jo2=new JSONObject();
        jo2.put("id", 1002);
        jo2.put("name", "平平");
        jo2.put("age", 19);
        JSONArray ja2=new JSONArray();
        ja2.put(jo1);
        ja2.put(jo2);
        JSONObject jo3=new JSONObject();
        jo3.put("id", 11);
        jo3.put("name", "JAVAEE-1704");
        jo3.put("stus",ja2);        
        String json=jo3.toString();
        System.out.println(json);

    }

}

 

 

（2）谷歌GSON解析

 

public class GSONTest {

    //解析
    @Test
    public void test1() {
        // 对象嵌套数组嵌套对象
        String json1 = "{'id':1,'name':'JAVAEE-1703','stus':[{'id':101,'name':'刘一','age':16}]}";
        // 数组
        String json2 = "['北京','天津','杭州']";

        Gson gson=new Gson();
        //1、
        //解析对象：第一个参数：待解析的字符串 第二个参数结果数据类型的Class对象
        Grade grade=gson.fromJson(json1, Grade.class);
        System.out.println(grade);

        //2、
        //解析数组要求使用Type
        ArrayList<String> list=gson.fromJson(json2, 
                new TypeToken<ArrayList<String>>(){}.getType());
        System.out.println(list);
    }

//生成
    @Test
    public void test2(){
        ArrayList<Student> list=new ArrayList<>();
        for(int i=1;i<3;i++){
            list.add(new Student(101+i, "码子", 20+i));
        }
        Grade grade=new Grade(100001,"张三", list);
        Gson gson=new Gson();
        //将对象转换为诶JSON格式字符串
        String json=gson.toJson(grade);
        System.out.println(json);

    }
}

 

 

（3）FastJSON

 

public class FASTJson {

    //解析
    @Test
    public void test1() {
        // 对象嵌套数组嵌套对象
        String json1 = "{'id':1,'name':'JAVAEE-1703','stus':[{'id':101,'name':'刘铭','age':16}]}";
        // 数组
        String json2 = "['北京','天津','杭州']";
        //1、
        //静态方法
        Grade grade=JSON.parseObject(json1, Grade.class);
        System.out.println(grade);
        //2、
        List<String> list=JSON.parseArray(json2, String.class);
        System.out.println(list);
    }

//生成
    @Test
    public void test2(){
        ArrayList<Student> list=new ArrayList<>();
        for(int i=1;i<3;i++){
            list.add(new Student(101+i, "码子", 20+i));
        }
        Grade grade=new Grade(100001,"张三", list);
        String json=JSON.toJSONString(grade);
        System.out.println(json);
    }
}

 

 

（4）jackSon解析JSON，SpringMVC内置的解析器

 

public class JackSonTest {

    //解析
    @Test
    public void test1() throws Exception{
        // 对象嵌套数组嵌套对象
        String json1 = "{\"id\":1,\"name\":\"JAVAEE-1703\",\"stus\":[{\"id\":101,\"name\":\"刘一\",\"age\":16}]}";
        // 数组
        String json2 = "[\"北京\",\"天津\",\"杭州\"]";
        //1、
        ObjectMapper mapper=new ObjectMapper();
        Grade grade=mapper.readValue(json1, Grade.class);
        System.out.println(grade);
        //2、
        ArrayList<String> list=mapper.readValue(json2, 
                new TypeReference<ArrayList<String>>() {
        });
        System.out.println(list);

    }
    //生成
    @Test
    public void test2() throws JsonProcessingException{
        ArrayList<Student> list=new ArrayList<>();
        for(int i=1;i<3;i++){
            list.add(new Student(101+i, "码子", 20+i));
        }
        Grade grade=new Grade(100001,"张三", list);
        ObjectMapper mapper=new ObjectMapper();
        //将对象转换为JSON格式字符串
        String json=mapper.writeValueAsString(grade);
        System.out.println(json);
    }
}