Java之JSON处理（JSONObject、JSONArray）

依赖包：json-20180130.jar

MAVEN地址：

         <dependency>
             <groupId>org.json</groupId>
             <artifactId>json</artifactId>
             <version>20180130</version>
         </dependency>

比较简单，一看就懂，源码如下：

 package json;

 import org.json.JSONArray;
 import org.json.JSONObject;

 import java.util.HashMap;
 import java.util.Map;

 /**
  * JSONObject和JSONArray使用：进行JSON对象转换和操作
  * JSONObject：处理JSON串，多种构造方法，可用于多类型转账。
  * JSONArray：JSON数组，有顺序
  */
 public class JsonFirst {
     public static void main(String[] args) {
         // 1、定义一个json对象
         JSONObject jo = new JSONObject();
         jo.put("id", "1");
         jo.put("name", "tom");
         jo.put("age", "25");
         System.out.println("1、JSONObject: " + jo);
         // 获取name值
         String name = jo.getString("name");
         System.out.println("查询name:" + name);

         // 2、定义一个Json数组，数组有顺序
         JSONArray ja = new JSONArray();
         ja.put(0, "yang");
         ja.put(1, "li");
         ja.put(2, "zhang");
         ja.put(4, "fouth");
         System.out.println("2、JSONArray数组: " + ja);
         // 获取第四个值
         String fouth = ja.getString(4);
         System.out.println("查询第四个：" + fouth);

         // 3、json中添加json对象组成复杂JSON
         jo.put("Object", ja);
         System.out.println("3、添加JSON对象后: " + jo);

         // 4、String转换为JSON（复杂JSON处理）
         String str = "{\"name\":\"tom\",\"Object\":[\"yang\",\"li\",\"zhang\",null,\"fouth\"],\"id\":\"1\",\"age\":\"25\"}";
         JSONObject jo2 = new JSONObject(str);
         System.out.println("4、String转换为JSON:" + jo2);
         System.out.println("name属性值:" + jo2.getString("name"));
         System.out.println("Object属性值:" + jo2.get("Object").toString());
         // 删除Object属性值
         jo.remove("Object");
         System.out.println("删除Object属性值:" + jo);

         // 5、map和JSON转换
         Map<String, String> map1 = new HashMap<String, String>();
         map1.put("name", "Alexia");
         map1.put("sex", "female");
         map1.put("age", "23");
         JSONObject jo3 = new JSONObject(map1);
         System.out.println("5.1 map转JSON:" + jo3);
         Map<String, Object> map2 = new HashMap<String, Object>();
         map2 = jo3.toMap();
         System.out.println("5.2 JSON转map:" + map2);

         // 6、JSONArray中添加map和JSON对象
         JSONArray jo4 = new JSONArray();
         jo4.put(map1);
         jo4.put(1, "333");
         jo4.put(jo);
         System.out.println("6、JSONArray中添加map和JSON对象：" + jo4);

     }
 }

运行结果：

1、JSONObject: {"name":"tom","id":"1","age":"25"}
查询name:tom
2、JSONArray数组: ["yang","li","zhang",null,"fouth"]
查询第四个：fouth
3、添加JSON对象后: {"name":"tom","Object":["yang","li","zhang",null,"fouth"],"id":"1","age":"25"}
4、String转换为JSON:{"name":"tom","Object":["yang","li","zhang",null,"fouth"],"id":"1","age":"25"}
name属性值:tom
Object属性值:["yang","li","zhang",null,"fouth"]
删除Object属性值:{"name":"tom","id":"1","age":"25"}
5.1 map转JSON:{"name":"Alexia","age":"23","sex":"female"}
5.2 JSON转map:{sex=female, name=Alexia, age=23}
6、JSONArray中添加map和JSON对象：[{"name":"Alexia","age":"23","sex":"female"},"333",{"name":"tom","id":"1","age":"25"}]