关于Java中read()函数的返回值的问题? [英] Issue regarding the return value of the read() function in java?

问题描述

可能重复:
为什么InputStream#read()返回int并不是一个字节?

为什么read()的返回类型是整数?

嘿，我只是在Java文档上浏览I/O流的资料，而只是在参考字节流时才碰到这个问题-如果输入是字节流，为什么read()不返回字节值?

Hey I was just surfing java docs for material on I/O streams and just came across this question specifically in reference to the byte streams - If the input is a stream of bytes, why doesn't read() return a byte value ?

我挠了一下头，但是想不出任何有力的答案，如果有人能帮助我，我将不胜感激.

I scratched my head for some time but couldn't think of any strong answer to the question I would be grateful if anyone can help.

推荐答案

这是因为 read 可以返回-1作为流结束(EOF)标记的指示符-即不再有字节从流中读取.

This is because read can return -1 as an indicator of end-of-stream (EOF) marker - i.e. no more bytes to be read from the stream.

更多详细信息: http://download.oracle.com/javase/1.4.2/docs/api/java/io/InputStream.html#read%28%29 .具体来说:

More details: http://download.oracle.com/javase/1.4.2/docs/api/java/io/InputStream.html#read%28%29 . Specifically:

如果由于流的末尾已经没有字节而没有可用的字节到达时，返回值-1.

If no byte is available because the end of the stream has been reached, the value -1 is returned.

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