java - JSON 解析错误。 key 存在但未找到

Question

这是我的代码片段。我正在尝试从 PUBNUB 向我的系统发送 JSON 消息并解析它。我的 key 是“CMD”。这是我从 pubnub {"CMD":"hey"}

发送的内容

public void successCallback(String channel, Object message) {


   Object PlainTextMessage = new AESDecrypt().Decrypt(message);
   JSONObject jsonMsg = new JSONObject(PlainTextMessage);
   try {
      String command = jsonMsg.getString("CMD");
      System.out.println(command);
   } catch (JSONException e) {
      // TODO Auto-generated catch block
   e.printStackTrace();
}

这是我得到的错误

org.json.JSONException: JSONObject["CMD"] not found. at org.json.JSONObject.get(JSONObject.java:405) at org.json.JSONObject.getString(JSONObject.java:586) at PubNub.Subscribe$1.successCallback(Subscribe.java:45) at com.pubnub.api.Callback.successWrapperCallback(Unknown Source) at com.pubnub.api.PubnubCore.invokeSubscribeCallback(Unknown Source) at com.pubnub.api.PubnubCore.access$1100(Unknown Source) at com.pubnub.api.PubnubCore$14.handleResponse(Unknown Source) at com.pubnub.api.SubscribeWorker.process(Unknown Source) at com.pubnub.api.Worker.run(Unknown Source) at java.lang.Thread.run(Thread.java:745)

我不知道我做错了什么。我尝试转义双引号，但没有用。谁能告诉我我做错了什么？
提前致谢

Answer 1

请参阅.org.json的文档

http://www.json.org/javadoc/org/json/JSONObject.html#JSONObject(java.lang.String)

JSONObject 的构造函数，接受一个字符串而不是一个对象，所以强制转换是必要的

JSON对象

public JSONObject(java.lang.String source)
           throws JSONException

Construct a JSONObject from a source JSON text string. This is the most commonly used JSONObject constructor.

参数:

source - A string beginning with { (left brace) and ending with } (right brace). Throws:

JSONException - If there is a syntax error in the source string or a duplicated key.