当涉及从finally块返回的值时，在try块中有return语句是好的做法 [英] Is it good practice to have return statement in try block when returned value from finally block is concerned

问题描述

我想知道，返回从尝试阻止这是不错的做法？

I was wondering, is it good practice to return from try block?

package debug;

/**
 *
 * @author Owner
 */
public class Main {

  public static void main(String[] args) {
    System.out.println(fun());
  }

  static boolean cleanup() {
    // Fail to cleanup.
    return false;
  }

  static boolean fun() {
    boolean everything_is_fine = true;
    try {
      System.out.println("open file stream");
      return everything_is_fine;
    } finally {
      everything_is_fine = cleanup();
    }
  }
}

---

我首先想到的是打印 false 。但是，这是输出：

open file stream
true

如您所见，如果我在中有 return 语句，请尝试阻止，我将错过最终清理期间的失败状态。

As you can see, if I am having return statement within try block, I will miss the fail status during finally cleanup.

我应该有代码为：

  static boolean fun() {
    boolean everything_is_fine = true;
    try {
      System.out.println("open file stream");      
    } finally {
      everything_is_fine = cleanup();
    }
    return everything_is_fine;
  }

只要涉及finally块的返回值，我避免从尝试返回？

推荐答案

您建议的代码（问题末尾）没问题。您可以从 finally 块返回，但您不应该 - 例如eclipse显示警告finally块无法正常完成。

Your suggested code (at the end of the question) is fine. You can return from the finally block, but you should not - for example eclipse shows a warning "finally block does not complete normally".

事实上， try / finally 与返回。这似乎是这样，因为它是方法中唯一的构造，但是之后你可以有其他代码（例如 - 事件通知），然后返回。

In fact, the try/finally aren't directly related to the return. It seems so here, because it is the only construct in the method, but you can have other code after that (for example - event notifications), and then return.

至于你的问题 - 如果已经返回 finally 块，则无法更改返回变量的值。所以不要从返回。

As for your question - you can't change the value of the returned variable in the finally block if it is already returned. So don't return from try.

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