try-finally和try-catch之间的区别

问题描述

两者之间有什么区别

try {
    fooBar();
} finally {
    barFoo();
}

和

try {
  fooBar();
} catch(Throwable throwable) {
    barFoo(throwable); // Does something with throwable, logs it, or handles it.
}

我更喜欢第二个版本，因为它使我可以使用Throwable.两种变体之间是否存在逻辑上的差异或偏好的约定?

I like the second version better because it gives me access to the Throwable. Is there any logical difference or a preferred convention between the two variations?

还可以通过finally子句访问异常吗?

Also, is there a way to access the exception from the finally clause?

推荐答案

这是两件事:

• 仅在try块中引发异常时才执行catch块.
• 无论是否引发异常，finally块总是在try(-catch)块之后执行.

在您的示例中，您没有显示第三个可能的构造:

In your example you haven't shown the third possible construct:

try {
    // try to execute this statements...
}
catch( SpecificException e ) {
    // if a specific exception was thrown, handle it here
}
// ... more catches for specific exceptions can come here
catch( Exception e ) {
    // if a more general exception was thrown, handle it here
}
finally {
    // here you can clean things up afterwards
}

而且，就像@codeca在他的评论中说的那样，无法访问finally块内部的异常，因为即使没有异常，也会执行finally块.

And, like @codeca says in his comment, there is no way to access the exception inside the finally block, because the finally block is executed even if there is no exception.

当然，您可以在变量外声明一个包含异常的变量，并在catch块内分配一个值.然后，您可以在finally块中访问此变量.

Of course you could declare a variable that holds the exception outside of your block and assign a value inside the catch block. Afterwards you can access this variable inside your finally block.

Throwable throwable = null;
try {
    // do some stuff
}
catch( Throwable e ) {
    throwable = e;
}
finally {
    if( throwable != null ) {
        // handle it
    }
}

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