Java解析Json字符串--数组或列表

Json示例：

 [
 {
 "age": 25,
 "gender": "female",
 "grades": "三班",
 "name": "露西",
 "weight": 51.3
 },
 {
 "age": 26,
 "gender": "male",
 "grades": "三班",
 "name": "杰克",
 "weight": 66.5
 },
 {
 "age": 25,
 "gender": "female",
 "grades": "三班",
 "name": "莉莉",
 "weight": 55
 }
 ]

我们来解析一下这个Json字符串。

首先，因为此Json字符串最外边是由一个中括弧”[]”包裹，那么，最终我们会用数组或者列表来接收它。

接下来，我们能看到中括弧里边有三个同级的大括弧，并且每个大括弧里包含的内容是相同的，大括弧我们可以对应创建一个类，我们创建一个类Student.java，并对应大括弧内的元素，定义相应的成员变量，生成get/set方法。

我们生成的Student.java如下：

 package com.bean;

 /**
 * 学生
 */
 public class Student {

 private int age;//年龄
 private String gender;//性别，male/female
 private String grades;//班级
 private String name;//姓名
 private float weight;//体重

 public int getAge() {
 return age;
 }
 public void setAge(int age) {
 this.age = age;
 }
 public String getGender() {
 return gender;
 }
 public void setGender(String gender) {
 this.gender = gender;
 }
 public String getGrades() {
 return grades;
 }
 public void setGrades(String grades) {
 this.grades = grades;
 }
 public String getName() {
 return name;
 }
 public void setName(String name) {
 this.name = name;
 }
 public float getWeight() {
 return weight;
 }
 public void setWeight(float weight) {
 this.weight = weight;
 }

 }

解析成数组或列表：

 package com.test;

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

 import net.sf.json.JSONArray;

 import com.bean.Student;

 public class Domain {

 @SuppressWarnings("unchecked")
 public static void main(String[] args) {

 String jsonStr = "[{\"age\": 25,\"gender\": \"female\",\"grades\": \"三班\",\"name\": \"露西\",\"weight\": 51.3},{\"age\": 26,\"gender\": \"male\",\"grades\": \"三班\",\"name\": \"杰克\",\"weight\": 66.5},{\"age\": 25,\"gender\": \"female\",\"grades\": \"三班\",\"name\": \"莉莉\",\"weight\": 55}]";

 JSONArray jsonArray = JSONArray.fromObject(jsonStr);

 Student[] stus = new Student[3];
 List<Student> list = new ArrayList<Student>();

 stus = (Student[]) JSONArray.toArray(jsonArray, Student.class);//转换成数组
 list = (List<Student>) JSONArray.toCollection(jsonArray, Student.class);//转换成列表

 }
 }

通过数组或者列表生成Json字符串：

 package com.test;

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

 import net.sf.json.JSONArray;

 import com.bean.Student;

 public class Domain {

 @SuppressWarnings("unchecked")
 public static void main(String[] args) {

 Student stu1 = new Student();
 Student stu2 = new Student();
 Student stu3 = new Student();

 stu1.setAge(25);
 stu1.setGender("female");
 stu1.setGrades("三班");
 stu1.setName("露西");
 stu1.setWeight(51.3f);

 stu2.setAge(26);
 stu2.setGender("male");
 stu2.setGrades("三班");
 stu2.setName("杰克");
 stu2.setWeight(66.5f);

 stu3.setAge(25);
 stu3.setGender("female");
 stu3.setGrades("三班");
 stu3.setName("莉莉");
 stu3.setWeight(55.0f);

 Student[] stus = new Student[3];
 List<Student> list = new ArrayList<Student>();

 stus[0] = stu1;
 stus[1] = stu2;
 stus[2] = stu3;

 list.add(stu1);
 list.add(stu2);
 list.add(stu3);

 String jsonStr1 = JSONArray.fromObject(stus).toString();
 String jsonStr2 = JSONArray.fromObject(list).toString();

 System.out.println(jsonStr1);
 System.out.println(jsonStr2);

 }
 }