使用ObjectInputStream读取文件时出现EOFException [英] EOFException when reading files with ObjectInputStream

问题描述

我基本上遇到了类似的问题：阅读objectinputstream时Java中的EOFexception ，但我找不到一个干净的代码的答案。

I basically have a similar problem as stated here: EOFexception in Java when reading objectinputstream, but I don't find an answer with clean code.

答案指出 ObjectInputStream＃readObject 将在读者到达时抛出异常文件的结尾。在网上寻找解决方案之后，我还没有找到解决方案。对于这种情况可能是一个好的和干净的解决方案吗？

The answer states that the ObjectInputStream#readObject will throw the exception when the reader reachs the End Of File. After looking in the web for a solution, I haven't found a solution. Could be a good and clean solution for this case?

注意：我已经尝试过这个（但它看起来很难看并且不是干净的代码）。我正在寻找更好的解决方案：

Note: I have tried this (but it looks ugly and is not clean code). I'm looking for a better solution:

ObjectInputStream ois = new ObjectInputStream(new FileInputStream(file));
try {
    Object o;
    while ((o = ois.readObject()) != null) {
        if (o instanceof MyClass) {
            MyClass m = (MyClass)o;
            //use the object...
        }
    }
} catch (EOFException eofex) {
    //do nothing
}  catch (IOException ioex) {
    throw ioex;
    //I have another try/catch block outside to control the life of the ObjectInputStream
}
//later in the code...
ois.close();

推荐答案

这就是应该发生的事情。你的代码错了。检查Javadoc。 readObject（）只返回 null 如果你写了 null 。它没有说任何关于在EOF返回null的事情。循环直到 readObject（）返回 null 只有在你写过 null时才会停止通过 writeObject（），如果没有，你将获得 EOFException 。

That's what's supposed to happen. Your code is wrong. Check the Javadoc. readObject() only returns null if you wrote a null. It doesn't say anything about returning a null at EOF. Looping until readObject() returns null will only stop if you ever wrote a null via writeObject(), and if you didn't you will get an EOFException.

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