从Java访问JSON字符串中的长值

Question

I want to get the value of the long "transmitBytes" in this JSON string

[

    {
       "portNumber" : 2,

       "queueId" : 0,

       "transmitBytes" : 1944145,

       "transmitPackets" : 1684,

       "transmitErrors" : 0
    }

]

I have used the org.json library and implemented the code:

    String queueJson = [{"portNumber":2,"queueId":0,"transmitBytes":1944145,"transmitPackets":1684,"transmitErrors":0}];

    System.out.println("The JSON string is: " + queueJson);


     JSONObject obj; 

     try { 
     obj = new JSONObject(queueJson); 
     long TXbytes =  obj.getLong("transmitBytes");
     System.out.println("The amount of transmittet bytes is " + TXbytes);
     } catch (JSONException e) { 
             // TODO Auto-generated catch block
     e.printStackTrace(); 
     }

The issue occurs, when I'm running the Apache tomcat web server. Following error occurs:

SEVERE: A child container failed during start

with following:

org.apache.catalina.LifecycleException: Failed to start component

When I remove the JSONObject class and the corresponding org.json library, everything works fine, and the server runs without any issues. Does anyone know why this issue occurs, and are there another libraries available to access a long value in a JSON string from Java ?.

Thanks in advance

Answer 1

Your JSON form is:

Array -> Object(s)

So you should first access array and then object

JSONArray array = new JSONArray(queueJson);
JSONObject obj = array.getJSONObject(0);

0 because it's the first index (the only one). The other code will be the same.

Another way is to fix your problem by editing your Json (if it's made by you) and make it return something like this:

{
    "portNumber": 2,
    "queueId": 0,
    "transmitBytes": 1944145,
    "transmitPackets": 1684,
    "transmitErrors": 0
}

Answer 2

try this code:

JSonArray array=new JSonArray(queueJson);

instead of obj = new JSONObject(queueJson);