JSON字符串转换为对象-蒲公英云

JSON字符串转换为对象

首先理解JSONObject 和JSONArray,JSONObject就代表{“key”:”value”,”key”:”value”}格式，不管多么复杂都是这种格式，JSONArray代表[{“key”:”value”},{“key”:”value”}]格式，原理一样，不管多么复杂，都是这种格式。

net.sf.json-lib

json-lib

2.4

jdk15

下面例子展示了怎么把对象转换成字符串，把复杂字符串解析成对象

package JSON.JSONObjectAndJSONArray;
import org.junit.Before;
import JSON.entity.Student;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
/**
 * Unit test for simple App.
 */
public class AppTest extends TestCase {
    /**
     * Create the test case
     *
     * @param testName
     *            name of the test case
     */
    public AppTest(String testName) {
        super(testName);
    }
    /**
     * @return the suite of tests being tested
     */
    public static Test suite() {
        return new TestSuite(AppTest.class);
    }
    /**
     * Rigourous Test :-)
     */
    @org.junit.Test
    public void testApp() {
        Student stu1 = new Student("001", "小红", "24");
        Student stu2 = new Student("002", "小黄", "25");
        Student stu3 = new Student("003", "小绿", "23");
        JSONObject jsonObject = new JSONObject();
        JSONArray jsonArray = new JSONArray();
        jsonObject.put("stu1", stu1);
        jsonObject.put("stu2", stu2);
        jsonObject.put("stu3", stu3);
        String jsonString = jsonObject.toString();
        System.out.println(jsonString);
        // {"stu1":{"age":"24","id":"001","name":"小红"},"stu2":{"age":"25","id":"002","name":"小黄"},"stu3":{"age":"23","id":"003","name":"小绿"}}
        jsonArray.add(stu1);
        jsonArray.add(stu2);
        jsonArray.add(stu3);
        System.out.println(jsonArray.toString());
        // [{"age":"24","id":"001","name":"小红"},{"age":"25","id":"002","name":"小黄"},{"age":"23","id":"003","name":"小绿"}]
        jsonObject = new JSONObject();
        jsonObject.put("student", jsonArray);
        System.out.println(jsonObject);
        // {"student":[{"age":"24","id":"001","name":"小红"},{"age":"25","id":"002","name":"小黄"},{"age":"23","id":"003","name":"小绿"}]}
        System.out.println("----------------");
        String str = "{\"stu1\":{\"age\":\"24\",\"id\":\"001\",\"name\":\"小红\"},\"stu2\":{\"age\":\"25\",\"id\":\"002\",\"name\":\"小黄\"},\"stu3\":{\"age\":\"23\",\"id\":\"003\",\"name\":\"小绿\"}}";
        JSONObject jsonObject2 = JSONObject.fromObject(str);
        Object object = jsonObject2.get("stu1");
        System.out.println(object);
        // {"age":"24","id":"001","name":"小红"}
        JSONObject jsonBean = JSONObject.fromObject(object);
        System.out.println("jsonBean---" + jsonBean);
        // jsonBean---{"age":"24","id":"001","name":"小红"}
        Object bean = JSONObject.toBean(jsonBean, Student.class);
        if (bean instanceof Student) {
            System.out.println(bean);
            // Student [id=001, name=小红, age=24]
        }
        System.out.println("--------------");
        String str2 = "{\"student\":[{\"age\":\"24\",\"id\":\"001\",\"name\":\"小红\"},{\"age\":\"25\",\"id\":\"002\",\"name\":\"小黄\"},{\"age\":\"23\",\"id\":\"003\",\"name\":\"小绿\"}]}";
        JSONObject jsonObject3 = JSONObject.fromObject(str2);
        Object object2 = jsonObject.get("student");
        JSONArray jsonArray2 = JSONArray.fromObject(object2);
        for (int i = 0; i < jsonArray2.size(); i++) {
            Object object3 = jsonArray2.get(i);
            JSONObject object4 = jsonObject.fromObject(object3);
            Object bean2 = JSONObject.toBean(object4, Student.class);
            if (bean2 instanceof Student) {
                System.out.println(bean2);
                /*
                 * Student [id=001, name=小红, age=24] 
                 * Student [id=002, name=小黄, age=25] 
                 * Student [id=003, name=小绿, age=23]
                 */
            }
        }
    }
}