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);


}
}