Java fastjson中JSONObject 常用的方法及相关转换

最新推荐文章于 2025-07-08 15:52:48 发布

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最新推荐文章于 2025-07-08 15:52:48 发布

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本文介绍了Java fastjson库中JSONObject的相关内容，包括其继承结构和常用方法。重点讲解了JSONObject如何转换为JSON字符串、从JSON字符串创建JSONObject、JavaBean与JSONObject之间的相互转换，以及将json数据解析为Map的技巧。

继承关系：

public abstract class JSON implements JSONStreamAware, JSONAware {}

public class JSONObject extends JSON implements Map<String, Object>, Cloneable, Serializable, InvocationHandler {}

public class JSONArray extends JSON implements List<Object>, Cloneable, RandomAccess, Serializable {}

1.JSONObject 的常用方法

//数据准备
	List<Student> list=new ArrayList<Student>();
	list.add(new Student(1,1000d,"旅游",new Date()));
	list.add(new Student(2,1500d,"玩电脑游戏",new Date()));
	list.add(new Student(3,3000d,"看电影",new Date()));
	Student student=new Student(1,1000d,"旅游",new Date());
	JSONObject jsonObject=new JSONObject();
	jsonObject.put("8", "签名");
	jsonObject.put("d", 10.0);
	jsonObject.put("date", new Date());
	jsonObject.put("stu", new Student(8,8000d,"购物",new Date()));
	jsonObject.put("arr", list);
	//相当于
	Map<String,Object> map=new HashMap<String, Object>();
	//常用方法
	//1.判断该JSONObject对象是否为空
	jsonObject.isEmpty();
	//2.获取键值对的数量
	jsonObject.size();
	//3.根据键获取value;
	jsonObject.get("1");
	jsonObject.getString("8");
	jsonObject.getDouble("d");
	Date date = jsonObject.getDate("date");
	System.out.println(date);
	//4.是否包含指定的key
	jsonObject.containsKey("1");
	//5.是否包含指定的value
	jsonObject.containsValue("签名");	
	//6.根据key获取对应的JSONObject对象
	System.out.println(jsonObject);
	JSONObject stuJson=jsonObject.getJSONObject("stu");
	           stuJson.put("bz", "好学生");
	           stuJson.put("hobby", "学习");
	           jsonObject.put("stu", stuJson);
     //将JSONObject转换为javaBean
         stuJson..toJavaObject(Student.class)
	System.out.println(stuJson);
	System.out.println(jsonObject);
	//7.根据key获取对应的JSONObject数组
	JSONArray arrJson=jsonObject.getJSONArray("arr");
     相当于List<Object> list=new ArrayList<Object>();
	//8.将数组转换为list
	List<Student> javaList = jsonObject.getJSONArray("arr").toJavaList(Student.class);
	System.out.println(arrJson);
	//9.将JSONObject转为json字符串
	String jsonString = jsonObject.toJSONString();
	System.out.println(jsonString);
	//10.public class JSONObject extends JSON implements Map<String, Object>, Cloneable, Serializable, InvocationHandler{}
	//具有map的特点
	Set<Entry<String, Object>> entrySet = jsonObject.entrySet();
	Iterator<Entry<String, Object>> iterator = entrySet.iterator();
	while(iterator.hasNext()){
		Entry<String, Object> next = iterator.next();
		System.out.println(next.getKey()+":"+next.getValue());
	}
	Set<String> keySet = jsonObject.keySet();
	Collection<Object> values = jsonObject.values();
	//11.根据key移除键值对
	jsonObject.remove("arr");
	//12.清楚所有的元素
	jsonObject.clear();

2.相关转换

JSONObject----》JSON字符串

  
	JSONObject jsonObject=new JSONObject();
    jsonObject.put("date", new Date());
     //JSONObject--->json 字符串
	String jsonString = jsonObject.toJSONString();

	//JSONObject--->json 字符串	
	String string = jsonObject.toString();

JSON字符串---》JSONObject

String jsonStr="{\"createRq\":1576647338750,\"hthm\":\"Beer00001\",\"hydm\":\"10000\",\"hymc\":\"10000\",\"hzmc\":\"Ibeer\",\"id\":1}";
	JSONObject parseObject = JSON.parseObject(jsonStr);

JavaBean----》JSONObject

//javaBen--->JSONObject
//1.将javaBen转换为JSON字符串
String jsonString2 = JSONObject.toJSONString(student);
//2.JSON字符串---》JSONObject
JSONObject parseObject = JSONObject.parseObject(jsonString2);

JSONObject------》JavaBean

 //JSONObject---->JavaBen
	    Student javaObject = JSONObject.toJavaObject(parseObject, Student.class);

json----》Map

  String strjson="{\"method\":\"OnEventNotify\",\"params\":{\"ability\":\"event_face_recognition\",\"events\":[{\"data\":{\"faceRecognitionResult\":{\"faceMatch\":[{\"certificate\":\"342623198710177156\",\"faceGroupCode\":\"6a4f52d1024f4b5ea391452e4c07d05c\",\"faceGroupName\":\"人脸分组1\",\"faceInfoCode\":\"7159c1037d434b93bb6af01f5bfaf685\",\"faceInfoName\":\"秦华\",\"faceInfoSex\":\"male\",\"facePicUrl\":\"http://10.67.184.86:80/FDLib?FDID=5EC907D0E97C49188342020A274AA9BE&pId=48D135B74EE447E7A336A7B5DEA97E5A&size=66455\",\"similarity\":0.029999999999999999}],\"snap\":{\"ageGroup\":\"young\",\"bkgUrl\":\"http://10.67.184.86:80/picture/Streaming/tracks/103/?name=ch0001_03000001329061154662400130164&size=130164\",\"faceTime\":\"2019-05-27 14:17:56\",\"faceUrl\":\"http://10.67.184.86:80/picture/Streaming/tracks/103/?name=ch0001_03000001329061153843200007456&size=7456\",\"gender\":\"female\",\"glass\":\"yes\"},\"srcEventId\":\"BE9A6EB8-4CCC-4D53-87FC-66BB28DA4A5A\"},\"resInfo\":[{\"cn\":\"184.156_6024_抓拍\",\"indexCode\":\"86f0d4c232fc4807af9f7b98490a5891\",\"resourceType\":\"camera\"}],\"srcEventId\":\"BE9A6EB8-4CCC-4D53-87FC-66BB28DA4A5A\"},\"eventId\":\"e91d79f5-543c-4e9f-8c4a-82a113e8d384\",\"eventType\":1644175361,\"happenTime\":\"2019-05-27T14:17:56.000+08:00\",\"srcIndex\":\"6a4f52d1024f4b5ea391452e4c07d05c\",\"srcName\":\"人脸分组1\",\"srcType\":\"facegroup\",\"status\":0,\"timeout\":0}],\"sendTime\":\"2019-05-27T14:17:50.747+08:00\"}}";
    
    Map map=(Map)JSON.parse(strjson);