本篇主要讲解 ArrayList 和 fastjson 中的 JSONArray相互转换的几种常用方式,以实体类 Student.java 举例说明
Student 实体类
public class Student {
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;
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.*;
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'}
本篇主要讲解 ArrayList 和 fastjson 中的 JSONArray相互转换的几种常用方式,以实体类 Student.java 举例说明Student 实体类public class Student { private String name; // 姓名 private Integer age; // 年龄 private String gender; // 性别 public Student(String name, Integer
String dataStr = (String) map.get("Data");
JSONArray parseArray = JSON.parseArray(dataStr);
List<SModel> sModelList = new ArrayList<SModel>();
sModelList = JSON.parseArray(parseArray....
一般大家都知道ArrayList和LinkedList的大致区别:
1.ArrayList是实现了基于动态数组的数据结构,LinkedList基于链表的数据结构。
2.对于随机访问get和set,ArrayList觉得优于LinkedList,因为LinkedList要移动指针。
3.对于新增和删除操作add和remove,LinedList比较占优势,因为ArrayList要移动数据。
ArrayList和LinkedList是两个集合类,用于存储一系列的对象引用(references)。例如我们可以用ArrayList来存储一系列的String或者Integer。那
public class Main {
public static void main(String[] args) {
ArrayList<String> arrayList = new ArrayList<>();
arrayList.add("element1");
arrayList.add("element2");
JSONArray jsonArray = new JSONArray();
for (String element : arrayList) {
jsonArray.put(element);
System.out.println(jsonArray.toString());
这个例子中,我们首先创建了一个 ArrayList,然后遍历它的元素,将每个元素添加到 JSONArray 中。最后,我们通过调用 jsonArray.toString() 方法将其转换为字符串并输出。