Java 投射导致 websocket 崩溃

Question

所以我有一个奇怪的问题。我正在连接到 websocket。

随着数据的流入，一切都很好。

@Override
public void onMessage(WebSocket webSocket, String text) 
{
      // My data looks like 
      // {"Type":3, "F":[1,2,3974.909912109375,27500,1639207185]}

      obj = new JSONObject(text);
      // Then I get the array in "F" key
      o = obj.getJSONArray("F");

     // I want to now cast these variables into variables to use.
   
     // So I do...
     Integer v = (Integer) o.get(0);
     Integer t = (Integer) o.get(1);

     // This works fine.  
     // If I stop here.....
     // the websocket stays connected, and keeps streaming....

     // However.... if I do this....
     Double p = (Double) o.get(2);

    // The websocket crashes, and disconnects??
    // Program continues running though and there is no exceptions.
    // Its merely disconnecting the socket for some reason, by casting?

 }

这是怎么回事？？为什么我不能将其转换为双倍数？

我也尝试过 Float，但没有成功。

有什么想法吗？？

伊娃也试过...

Double p = new Double((Integer) o.get(2));
Double p = new Double((Float) o.get(2));
Float p = (Float) o.get(2);
float p = (float) o.get(2);
double p  = Double.parseDouble((String) o.get(2));

所有这些 crash/disconnect websocket。

似乎当我尝试访问索引 2 时，事情变得不稳定。
然而....

我可以

System.out.println(o.get(2));

很好，它会打印

3974.909912109375

Answer 1

您不能将其直接转换为 Double。而是尝试使用

Double p = Double.parseDouble(o.get(2));

话虽这么说，但保持数据一致并将所有内容都转换为 Double 可能会更好，这样可以避免后续出现问题。

String text = "1,2,3974.909912109375,27500,1639207185";
String[] inputs = text.split(",");
List<Double> doubles = Arrays.stream(inputs)
    .map(Double::parseDouble)
    .collect(Collectors.toList());

Java 投射导致 websocket 崩溃

Java Casting crashes websocket

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