exception.getMessage（）输出与类名 [英] exception.getMessage() output with class name

问题描述

我正在尝试解决一个问题，在我的应用程序中我有这个代码

I'm trying to fix an issue, in my application I have this code

try {
  object1.method1();
} catch(Exception ex) {
   JOptionPane.showMessageDialog(nulll, "Error: "+ex.getMessage());
}

，对象1将执行以下操作：

and the object1 would do something like that:

public void method1() {
   //some code...
   throw new RuntimeException("Cannot move file");
}

我在我的选项窗格中收到如下错误消息：
错误：java.lang.RuntimeException：无法移动文件

I get a messsage in my option pane like this: Error: java.lang.RuntimeException: Cannot move file

但我使用 getMessage 而不是 toString 方法，所以类的名称不应该出现，对吗？

but I used getMessage and not toString method, so the name of the class shouldn´t appear, right?

我已经尝试了很多例外，甚至 Exception 本身。我正在寻求解决这个问题，而无需实现我自己的异常子类

What I am doing wrong? I already tryied with a lot of exceptions, even Exception itself. I'm looking to solve this no without the need to implement my own Exception subclass

解决问题 - 感谢大家！

从SwingWorker的 get（）方法中，try和catch实际上被调用， code> ExecutionException 我从 doInBackground（）抛出我的异常
我修复了这样做：

The try and catch were actually being called in get() method from SwingWorker which constructs an ExecutionException with my exception thrown from doInBackground() I fixed doing this:

@Override
protected void done() {
    try {
        Object u = (Object) get();
        //do whatever u want
    } catch(ExecutionException ex) {
        JOptionPane.showMessageDialog(null, "Error: "+ex.getCause().getMessage());
    } catch(Exception ex) {
        JOptionPane.showMessageDialog(null, "Error: "+ex.getMessage());
    }
}

推荐答案

认为你正在将异常包装在另一个异常中（这不在你的代码上面）。如果您尝试以下代码：

I think you are wrapping your exception in another exception (which isn't in your code above). If you try out this code:

public static void main(String[] args) {
    try {
        throw new RuntimeException("Cannot move file");
    } catch (Exception ex) {
        JOptionPane.showMessageDialog(null, "Error: " + ex.getMessage());
    }
}

...你会看到一个完全正确的弹出窗口你需要什么。

...you will see a popup that says exactly what you want.

但是，为了解决你的问题（包装的异常），你需要得到根异常与正确的消息。为此，您需要创建一个自己的递归方法 getRootCause ：

However, to solve your problem (the wrapped exception) you need get to the "root" exception with the "correct" message. To do this you need to create a own recursive method getRootCause:

public static void main(String[] args) {
    try {
        throw new Exception(new RuntimeException("Cannot move file"));
    } catch (Exception ex) {
        JOptionPane.showMessageDialog(null,
                                      "Error: " + getRootCause(ex).getMessage());
    }
}

public static Throwable getRootCause(Throwable throwable) {
    if (throwable.getCause() != null)
        return getRootCause(throwable.getCause());

    return throwable;
}

注意：解开这样的异常， 。我鼓励你找出为什么例外被包装，问问自己是否有意义。

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