java如何获取json数组长度 java获取json数组对象的值

基本的JSONArray与JSONObject操作，还是挺简单的，但是自己鼓捣半天啊，把结果和代码记录下。

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class JsonTest {

    public static void main(String[] args) {
        //待读取的JSON文件
        String json="{'name':'xiaobai','school':[{'name1':'xiaoxue'},{'name1':'zhongxue'}]}";

        //建立一个JSON对象
        JSONObject jsonObject=JSONObject.fromObject(json);
        //读取对象值,由键索引键值，
        System.out.println(jsonObject.get("name"));
        System.out.println(jsonObject.get("school"));
        //System.out.println(jsonObject.get("school").toString());

        //读取数组
        JSONArray jsonArray=JSONArray.fromObject(jsonObject.get("school").toString());
        //System.out.println(jsonArray.size());

        //for循环读取数组里面的值
        for(int i=0;i<jsonArray.size();i++){
            JSONObject o=JSONObject.fromObject(jsonArray.get(i).toString());
            System.out.println(o.get("name1"));
            if(o.get("name1").equals("zhongxue")){
                System.out.println("这是中学");
            }
        }
    }
}

输出结果：

xiaobai
[{"name1":"xiaoxue"},{"name1":"zhongxue"}]
xiaoxue
zhongxue
这是中学

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class Jsontest1 {

    public static void main(String[] args) {
        //待读取的JSON文件
        String json1 = "{\"cat\":\"it\",//string类型\n" +
                "\"languages\":[\n" +
                "{\"id\":1,\"ide\":\"Eclipse\",\"name\":\"Java\"},\n" +
                "{\"id\":2,\"ide\":\"XCode\",\"name\":\"Swift\"},\n" +
                "{\"id\":3,\"ide\":\"Visual Studio\",\"name\":\"C#\"}\n" +
                "],//整型\n" + "\"pop\":ture//布尔类型\n" + "}";

        //建立一个JSON对象
        JSONObject jsonObject1 = JSONObject.fromObject(json1);
        //读取对象值,由键索引键值，
        System.out.println(jsonObject1.get("cat"));
        System.out.println(jsonObject1.get("pop"));
        System.out.println(jsonObject1.get("languages"));

        //读取数组
        //for循环读取数组里面的值
        JSONArray jsonArray1 = JSONArray.fromObject(jsonObject1.get("languages"));

        if (jsonArray1.size() != 0) {
            for (int i = 0; i < jsonArray1.size(); i++) {
                System.out.println(jsonArray1.get(i));
                String json2 = jsonArray1.get(i).toString();
                JSONObject jsonObject2 = JSONObject.fromObject(json2);
                System.out.println(jsonObject2.get("id"));
                System.out.println(jsonObject2.get("ide"));
                System.out.println(jsonObject2.get("name"));
            }
        }
    }
}

运行结果：
it
ture
[{"id":1,"ide":"Eclipse","name":"Java"},{"id":2,"ide":"XCode","name":"Swift"},{"id":3,"ide":"Visual Studio","name":"C#"}]
{"id":1,"ide":"Eclipse","name":"Java"}
1
Eclipse
Java
{"id":2,"ide":"XCode","name":"Swift"}
2
XCode
Swift
{"id":3,"ide":"Visual Studio","name":"C#"}
3
Visual Studio
C#