{
    "result": 1,
    "personData": [
        {
            "name": "Tom Green",
            "age": 22,
            "url": "https://img.alicdn.com/imgextra/i2/2578685019/TB21XA7iXXXXXbxXpXXXXXXXXXX_!!2578685019.jpg",
            "schoolInfo": [
                {
                    "school_name": "Cambridge"
 

                },
                {
                    "school_name": "Oxford"
                }
            ]
        },
        {
            "name": "Bill Gates",
            "age": 66,
            "url": "https://img.alicdn.com/tps/TB1PebaLXXXXXX3XpXXXXXXXXXX-990-500.jpg",
            "schoolInfo": [
                {
                    "school_name
 
": "北京大學"
                },
                {
                    "school_name": "清華大學"
                }
            ]
        }
    ]
}

Google gson地址：https://github.com/google/gson，將jar包下載後匯入到java工程中即可。我們來分析一下上述json資料，包括兩個元素，第一個是result，int型資料，第二個元素是personData，是一個物件（假設是Person物件）的集合，其中這個Person物件又包含了一個schoolInfo物件的集合。每個schoolInfo物件中只包含了一個school_name屬性。下面新建一個Java工程進行上述json資料的生成。
1 SchoolInfo.java

package www.imooc.com;

public class SchoolInfo {
    private String school_name;

    public String getSchool_name() {
        return school_name;
    }

    public void setSchool_name(String school_name) {
        this.school_name = school_name;
    }
}

Person.java

package www.imooc.com;

import java.util.List;

public class Person {
    private String name;
    private int age;
    private String url;
    private List<SchoolInfo> schoolInfo;//SchoolInfo是一個SchoolInfo物件的集合
    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 getUrl() {
        return url;
    }
    public void setUrl(String url) {
        this.url = url;
    }
    public List<SchoolInfo> getSchoolInfo() {
        return schoolInfo;
    }
    public void setSchoolInfo(List<SchoolInfo> schoolInfo) {
        this.schoolInfo = schoolInfo;
    }       
}

Result.java

package www.imooc.com;

import java.util.List;


/*
 * Result包括一個int型別資料，一個Person類物件的集合
 * */

public class Result {
    private int result;
    private List<Person> personData;
    public int getResult() {
        return result;
    }
    public void setResult(int result) {
        this.result = result;
    }
    public List<Person> getPersonData() {
        return personData;
    }
    public void setPersonData(List<Person> personData) {
        this.personData = personData;
    }


}

2 新建TestJson.java，生成json

package www.imooc.com;

import java.util.ArrayList;
import java.util.List;

import com.google.gson.Gson;

public class TestJson {

    public static void main(String[] args) {
        //設定result的資料,包括一個int資料和一個Person物件的集合
        Result result = new Result();
        result.setResult(1);
        List<Person> listPersons = new ArrayList<Person>();
        //設定result類中的第一個Person物件,包括name,age,url和一個SchoolInfo物件的集合       
        Person person1 = new Person();
        person1.setName("Tom Green");
        person1.setAge(22);
        person1.setUrl("https://img.alicdn.com/imgextra/i2/2578685019/TB21XA7iXXXXXbxXpXXXXXXXXXX_!!2578685019.jpg");
        //設定Person類中的SchoolInfo,包括一個school_name
        List<SchoolInfo> listSchoolInfo1 = new ArrayList<SchoolInfo>(); 
        SchoolInfo schoolInfo1 = new SchoolInfo();
        schoolInfo1.setSchool_name("Cambridge");
        SchoolInfo schoolInfo2 = new SchoolInfo();
        schoolInfo2.setSchool_name("Oxford");       
        listSchoolInfo1.add(schoolInfo1);
        listSchoolInfo1.add(schoolInfo2);                           
        person1.setSchoolInfo(listSchoolInfo1);//將SchoolInfo的物件集合新增到Person中
        //設定result類中的第二個Person物件,包括name,age,url和一個SchoolInfo物件的集合       
        Person person2 = new Person();
        person2.setName("Bill Gates");
        person2.setAge(66);
        person2.setUrl("https://img.alicdn.com/tps/TB1PebaLXXXXXX3XpXXXXXXXXXX-990-500.jpg");
        //設定Person類中的SchoolInfo,包括一個school_name
        List<SchoolInfo> listSchoolInfo2 = new ArrayList<SchoolInfo>(); 
        SchoolInfo schoolInfo3 = new SchoolInfo();
        schoolInfo3.setSchool_name("北京大學");
        SchoolInfo schoolInfo4 = new SchoolInfo();
        schoolInfo4.setSchool_name("清華大學");     
        listSchoolInfo2.add(schoolInfo3);
        listSchoolInfo2.add(schoolInfo4);                           
        person2.setSchoolInfo(listSchoolInfo2);//將SchoolInfo的物件集合新增到Person中

        listPersons.add(person1);//將Person物件的集合新增到Result中
        listPersons.add(person2);//將Person物件的集合新增到Result中   
        result.setPersonData(listPersons);

        Gson gson = new Gson();
        System.out.println(gson.toJson(result));//將上述設定的程式碼轉為json
    }

}