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Code  ›  Java 语言 ArrayList 和 JSONArray 相互转换__jsonarray转换成list
https://blog.51cto.com/u_12295205/3132901
宽容的毛衣
1 年前
private String name; // 姓名 private Integer age; // 年龄 private String gender; // 性别 public Student(String name, Integer age, String gender) { this.name = name; this.age = age; this.gender = gender; public String getName() { return name; public void setName(String name) { this.name = name; public Integer getAge() { return age; public void setAge(Integer age) { this.age = age; public String getGender() { return gender; public void setGender(String gender) { this.gender = gender; @Override public String toString() { return "Student{" + "name='" + name + ''' + ", age=" + age + ", gender='" + gender + ''' +

ArrayList 转成 JSONArray

简单总结了 6 种 方法（推荐 第5、6种），代码如下： 

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import java.util.ArrayList;
 * @author Miracle Luna
 * @version 1.0
 * @date 2019/7/5 17:43
public class ArrayListToJSONArray {
    public static void main(String[] args) {
        ArrayList<Student> studentList = new ArrayList<Student>();
        JSONArray studentJsonArray = new JSONArray();
        Student John = new Student("John", 16,"boy");
        Student Lily = new Student("Lily", 17, "girl");
        Student Jack = new Student("Jack", 18, "boy");
        studentList.add(John);
        studentList.add(Lily);
        studentList.add(Jack);
        System.out.println("=============== studentList info ================");
        System.out.println(studentList.toString());
        // 方式 1
        studentJsonArray = JSON.parseArray(JSONObject.toJSONString(studentList));
        System.out.println("n方式 1: " + studentJsonArray.toJSONString());
        // 方式 2
        studentJsonArray = JSON.parseArray(JSON.toJSONString(studentList));
        System.out.println("n方式 2: " + studentJsonArray.toJSONString());
        // 方式 3
        studentJsonArray = JSONObject.parseArray(JSONObject.toJSONString(studentList));
        System.out.println("n方式 3: " + studentJsonArray.toJSONString());
        // 方式 4
        studentJsonArray = JSONObject.parseArray(JSON.toJSONString(studentList));
        System.out.println("n方式 4: " + studentJsonArray.toJSONString());
        // 方式 5
        studentJsonArray = JSONArray.parseArray(JSONObject.toJSONString(studentList));
        System.out.println("n方式 5: " + studentJsonArray.toJSONString());
        // 方式 6
        studentJsonArray = JSONArray.parseArray(JSON.toJSONString(studentList));
        System.out.println("n方式 6: " + studentJsonArray.toJSONString());
        System.out.println("n============== Lambda 表达式 遍历 JSONArray ============");
        studentJsonArray.forEach(student -> System.out.println("student info: " + student));

执行结果如下：


=============== studentList info ================
[Student{name='John', age=16, gender='boy'}, Student{name='Lily', age=17, gender='girl'}, Student{name='Jack', age=18, gender='boy'}]
方式 1: [{"gender":"boy","name":"John","age":16},{"gender":"girl","name":"Lily","age":17},{"gender":"boy","name":"Jack","age":18}]
方式 2: [{"gender":"boy","name":"John","age":16},{"gender":"girl","name":"Lily","age":17},{"gender":"boy","name":"Jack","age":18}]
方式 3: [{"gender":"boy","name":"John","age":16},{"gender":"girl","name":"Lily","age":17},{"gender":"boy","name":"Jack","age":18}]
方式 4: [{"gender":"boy","name":"John","age":16},{"gender":"girl","name":"Lily","age":17},{"gender":"boy","name":"Jack","age":18}]
方式 5: [{"gender":"boy","name":"John","age":16},{"gender":"girl","name":"Lily","age":17},{"gender":"boy","name":"Jack","age":18}]
方式 6: [{"gender":"boy","name":"John","age":16},{"gender":"girl","name":"Lily","age":17},{"gender":"boy","name":"Jack","age":18}]
============== Lambda 表达式 遍历 JSONArray ============
student info: {"gender":"boy","name":"John","age":16}
student info: {"gender":"girl","name":"Lily","age":17}
student info: {"gender":"boy","name":"Jack","age":18}


JSONArray 转成 ArrayList


简单总结了 7 种 方法（推荐前 4种），代码如下：


import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import java.util.*;
 * @author Miracle Luna
 * @version 1.0
 * @date 2019/7/5 18:36
public class JSONArrayToArrayList {
    public static void main(String[] args) {
        JSONArray studentJSONArray = new JSONArray();
        List<Student> studentList = new ArrayList<Student>();
        Map<String, Object> JohnMap = new HashMap<String, Object>();
        JohnMap.put("name", "John");
        JohnMap.put("age", 16);
        JohnMap.put("gender", "boy");
        JSONObject John = new JSONObject(JohnMap);
        Map<String, Object> LilyMap = new HashMap<String, Object>();
        LilyMap.put("name", "Lily");
        LilyMap.put("age", 17);
        LilyMap.put("gender", "girl");
        JSONObject Lily = new JSONObject(LilyMap);
        Map<String, Object> JackMap = new HashMap<String, Object>();
        JackMap.put("name", "Jack");
        JackMap.put("age", 18);
        JackMap.put("gender", "boy");
        JSONObject Jack = new JSONObject(JackMap);
        studentJSONArray.add(John);
        studentJSONArray.add(Lily);
        studentJSONArray.add(Jack);
        System.out.println("n=============== studentJSONArray info ================");
        System.out.println(studentJSONArray);
        System.out.println("n=============== JSONArray to ArrayList(方式 1) ================");
        studentList = studentJSONArray.toJavaList(Student.class);
        studentList.forEach(student -> System.out.println("stundet info: " + student));
        System.out.println("n=============== JSONArray to ArrayList(方式 2) ================");
        studentList = JSON.parseArray(studentJSONArray.toJSONString(), Student.class);
        studentList.forEach(student -> System.out.println("stundet info: " + student));
        System.out.println("n=============== JSONArray to ArrayList(方式 3) ================");
        studentList = JSONObject.parseArray(studentJSONArray.toJSONString(), Student.class);
        studentList.forEach(student -> System.out.println("stundet info: " + student));
        System.out.println("n=============== JSONArray to ArrayList(方式 4) ================");
        studentList = JSONArray.parseArray(studentJSONArray.toJSONString(), Student.class);
        studentList.forEach(student -> System.out.println("stundet info: " + student));
        System.out.println("n=============== JSONArray to ArrayList(方式 5) ================");
        final ArrayList<Student> tmpList = new ArrayList<Student>();
        studentJSONArray.forEach(studentJson -> {
            JSONObject jsonObject = (JSONObject)studentJson;
            Student student = new Student(jsonObject.getString("name"), jsonObject.getInteger("age"), jsonObject.getString("gender"));
            tmpList.add(student);
        studentList = tmpList;
        studentList.forEach(student -> System.out.println("stundet info: " + student));
        System.out.println("n=============== JSONArray to ArrayList(方式 6) ================");
        studentList.clear();
        for (Object object : studentJSONArray) {
            JSONObject jsonObject = (JSONObject)object;
            Student student = new Student(jsonObject.getString("name"), jsonObject.getInteger("age"), jsonObject.getString("gender"));
            studentList.add(student);
        studentList.forEach(student -> System.out.println("stundet info: " + student));
        System.out.println("n=============== JSONArray to ArrayList(方式 7) ================");
        studentList.clear();
        for (int i = 0; i < studentJSONArray.size(); i++) {
            JSONObject jsonObject = (JSONObject)studentJSONArray.get(i);
            Student student = new Student(jsonObject.getString("name"), jsonObject.getInteger("age"), jsonObject.getString("gender"));
            studentList.add(student);
        studentList.forEach(student -> System.out.println("stundet info: " + student));

执行结果如下：


=============== studentJSONArray info ================
[{"gender":"boy","name":"John","age":16},{"gender":"girl","name":"Lily","age":17},{"gender":"boy","name":"Jack","age":18}]
=============== JSONArray to ArrayList(方式 1) ================
stundet info: Student{name='John', age=16, gender='boy'}
stundet info: Student{name='Lily', age=17, gender='girl'}
stundet info: Student{name='Jack', age=18, gender='boy'}
=============== JSONArray to ArrayList(方式 2) ================
stundet info: Student{name='John', age=16, gender='boy'}
stundet info: Student{name='Lily', age=17, gender='girl'}
stundet info: Student{name='Jack', age=18, gender='boy'}
=============== JSONArray to ArrayList(方式 3) ================
stundet info: Student{name='John', age=16, gender='boy'}
stundet info: Student{name='Lily', age=17, gender='girl'}
stundet info: Student{name='Jack', age=18, gender='boy'}
=============== JSONArray to ArrayList(方式 4) ================
stundet info: Student{name='John', age=16, gender='boy'}
stundet info: Student{name='Lily', age=17, gender='girl'}
stundet info: Student{name='Jack', age=18, gender='boy'}
=============== JSONArray to ArrayList(方式 5) ================
stundet info: Student{name='John', age=16, gender='boy'}
stundet info: Student{name='Lily', age=17, gender='girl'}
stundet info: Student{name='Jack', age=18, gender='boy'}
=============== JSONArray to ArrayList(方式 6) ================
stundet info: Student{name='John', age=16, gender='boy'}
stundet info: Student{name='Lily', age=17, gender='girl'}
stundet info: Student{name='Jack', age=18, gender='boy'}
=============== JSONArray to ArrayList(方式 7) ================
stundet info: Student{name='John', age=16, gender='boy'}
stundet info: Student{name='Lily', age=17, gender='girl'}
stundet info: Student{name='Jack', age=18, gender='boy'}
 
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