java - 附加代码是否可以防止打开文件泄漏

Question

假设 Java6，此代码是否可以避免文件描述符泄漏：

{
    InputStream in = fileObject.getReadStream();
    // fileObject cleans it's internal state in case it throws exception
    try {
        // do whatever, possibly throwing exception
    } finally {
        try {
            in.close();
        } catch (Exception ex) {
            // failure to close input stream is no problem
        }
    }
}

---

编辑：为了让问题看起来不那么明显，换句话说，上面的代码等于这个更长的代码：

{
    InputStream in = null;
    try {
        in = fileObject.getReadStream();
        // fileObject cleans it's internal state in case it throws exception

        // do whatever, possibly throwing exception
    } finally {
        if (in != null) {
            try {
                in.close();
            } catch (Exception ex) {
                // failure to close input stream is no problem
            }
        }
    }
}

也就是说，对返回打开的流或抛出异常的方法的调用是紧接在 之前try还是在try块内是否重要？

Answer 1

是的，很好。甚至不值得回答。一个变体（我较少使用）是：

InputStream in = null;
try {
    in = fileObject.getReadStream();
    // do whatever, possibly throwing exception
} finally {
    if (in  != null) {
        try {
           in.close();
        } catch (Exception ex) {
            // failure to close input stream is no problem if everything else was ok
        }
    }
}

Answer 2

我是一个对Java不太熟悉的学生，但我希望能对你有所帮助。我认为这段代码不能让你避免文件描述符泄漏的问题。尽管您已经尝试关闭 in.close 方法，但是如果 in.close 方法抛出一些异常，这将无济于事。