即使你抛出一个新的异常，finally块是否运行？ [英] Does a finally block run even if you throw a new Exception?

问题描述

在这段代码中，即使执行了catch块并且抛出了第二个异常，

In this code will someVar be set even if the catch block is executed and the second Exception is thrown?

public void someFunction() throws Exception {
    try {
        //CODE HERE
    } catch (Exception e) {
        Log.e(TAG, "", e);
        throw new Exception(e);
    } finally {
        this.someVar= true;
    }
}

推荐答案

是，finally块总是运行...除了：

Yes, the finally blocks always runs... except when:

• 运行try-catch-finally块的线程被杀死或中断
• 
  
• 您使用 System.exit（0）;


• 底层虚拟机在其他一些方式


• 底层硬件在某种程度上不可用

此外，如果您的finally块抛出一个未捕获的异常，那么之后什么都不会被执行（即异常将被抛出，就像在任何其他代码中）。发生这种情况的一个很常见的情况是 java.sql.Connection.close（）。

Additionally, if a method in your finally block throws an uncaught exception, then nothing after that will be executed (i.e. the exception will be thrown as it would in any other code). A very common case where this happens is java.sql.Connection.close().

除此之外，我猜测你使用的代码示例只是一个例子，但要注意把实际的逻辑放在finally块中。 finally块用于资源清理（关闭DB连接，释放文件句柄等），而不是用于必须运行的逻辑。如果它必须运行在try-catch块之前，远离可能会引发异常的东西，因为你的意图几乎肯定在功能上是一样的。

As an aside, I am guessing that the code sample you have used is merely an example, but be careful of putting actual logic inside a finally block. The finally block is intended for resource clean-up (closing DB connections, releasing file handles etc), not for must-run logic. If it must-run do it before the try-catch block, away from something that could throw an exception, as your intention is almost certainly functionally the same.

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