java - 如何将 JSONObject 转换为 java 对象

Question

我有一个Event使用构建器模式设置字段并最终将字段添加到 JSON 的类对象。

public class Event{

  private EventProcessor eventProcessor = new EventProcessor();
  private String userName;
  private String userID;

  public Event setUserName(String userName){
     this.userName = userName;
     return this;
  }
  public Event setUserID(String userID){
     this.userID = userID;
     return this;
}

  public void toJson(){
   JSONObject json = new JSONObject();

   if(null != userName)
   json.put("userName", userName);
   if(null != userID)
   json.put("userID", userID);

  // need help to convert json to "event"
   eventProcessor.addToQueue(event);
  }
 }

EventProcessor 类

  public class EventProcessor{

   static{
  EventQueue eventQueue = new EventQueue<Event>();
 }

  public void addToQueue(Event event){

    eventQueue.add(event);
   }

 }

我曾经通过json进入eventProcessor.addToQueue()方法和设置eventQueue = new EventQueue<JSONObejct>()和public void addToQueue(JSONObject event) 。这对我有用。但现在我需要将 POJO 传递给 addToQueue(Event event)方法。如何更改代码并转换 json结果为event对象并将其作为参数传递给 addToQueue(Event event)方法？

Answer 1

1. 您可以使用Gson将JSONObject转换为java POJO:

   Event event = gson.fromJson(json.toString(), Event.class);
   

2. 您可以使用 Jackson 来执行相同的操作:

   ObjectMapper objectMapper = new ObjectMapper();
   Event event = objectMapper.readValue(json.toString(), Event.class);