尝试资源：必须抛出或捕获close（）方法的异常？ [英] Try-with-resources: Must I throw or catch the close() method's exceptions?

问题描述

如果错误，请更正我：在Java 7的try-with-resources语句中，资源的 close（）方法抛出的任何异常都必须声明为抛出通过我的方法，或者我必须将另一个 try 中的整个尝试包装起来，它捕获由 close（）引发的任何异常。 / p>

如果是这样，我不得不怀疑我会不会使用它。我肯定不想要 throw 由 close（）抛出的异常，调用者不知道做到这一点并且尝试包装另一个尝试只是为了处理 close（）至少不会看起来很优雅。

编辑：我想我不小心问了两个问题，其中一个是重复的

问题1.我必须声明我的方法从 close（）方法中抛出异常，将try-with-resources包装在另一个尝试中？ （在建议的副本中未回答）

问题2.有没有办法静默关闭资源？ （显然是一个重复的，所以我把这个句子拿出来了，希望这个问题令人满意的是唯一的。）

解决方案

报价来自 Java语言规范（$ 14.20.3.2）：

14.20.3.2扩展的试用资源

$具有至少一个catch子句和/或finally
子句的try-with-resources 语句的b $ b

称为扩展的try-with-resources语句。
扩展的try-with-resources语句的含义：

     try 资源规范

        块_
     捕获 _
     最后 _opt

由以下翻译提供给基本的 try-with-resources 语句
（§14.20.3.1）嵌套在一个 try-catch 或 try-finally 或 try-catch-finally
语句：

     try {_
         try ResourceSpecification br />
            块_
    } br />
 &nbs p;   捕获 _opt

     / em> _opt

翻译的效果是把ResourceSpecification放在里面尝试
语句。这允许扩展的try-with-resources语句
的catch子句由于自动初始化或关闭任何资源而捕获异常。

所以，基本上，包装器已经实现了

Please correct me if this is wrong: In Java 7's try-with-resources statement, any exceptions thrown by the resource's close() method must be either declared as thrown by my method or I must wrap the whole try in another try which catches any exceptions thrown by close().

If so, I have to wonder if I will make much use of it. I certainly don't want to throw the exceptions thrown by close(), the caller won't know what to do with that. And a try wrapping another try just to handle close() would not look very elegant, to me at least.

EDIT: I think I accidentally asked two questions, one of which was a duplicate.

Question 1. Do I have to declare that my method throws the exception from the close() method or wrap the try-with-resources in another try? (Not answered in proposed duplicate.)

Question 2. Is there a way to close the resource silently? (Clearly a duplicate, so I am taking that sentence out of the question. Hopefully this makes the question satisfactorily unique.)

解决方案

Quote from Java Language Specification ($14.20.3.2):

14.20.3.2 Extended try-with-resources

A try-with-resources statement with at least one catch clause and/or a finally clause is called an extended try-with-resources statement. The meaning of an extended try-with-resources statement:

    try ResourceSpecification
        Block
    Catches_opt
    Finally_opt

is given by the following translation to a basic try-with-resources statement (§14.20.3.1) nested inside a try-catch or try-finally or try-catch-finally statement:

    try {
        try ResourceSpecification
            Block
    }
    Catches_opt
    Finally_opt

The effect of the translation is to put the ResourceSpecification "inside" the try statement. This allows a catch clause of an extended try-with-resources statement to catch an exception due to the automatic initialization or closing of any resource.

So, basically, wrapper is already implemented

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