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FileInputStream是否具有内部缓冲区

[英]Does FileInputStream have an internal buffer

原文 2011-09-16 15:24:29 1 2 java/ performance/ file-io

This question includes the following surpising (to me) assertion 这个问题包括以下令人惊讶的（对我而言）断言

both Java and Perl try quite hard to find a one-size-fits all default buffer size when reading in files 在读取文件时，Java和Perl都很难找到一个适合所有默认缓冲区大小

The Javadoc for FileInputStream however makes no mention of the class having its own buffer. 然而， FileInputStream的Javadoc没有提到具有自己的缓冲区的类。 And why should it, given that there is a BufferedInputStream class? 既然有一个BufferedInputStream类，它为什么要这样呢？ Do objects of class FileInputStream have their own buffer? 类FileInputStream对象有自己的缓冲区吗？ I realize that the O/S itself will have buffers; 我意识到O / S本身会有缓冲区; I'm not asking about those. 我不是在问这些问题。

2 个解决方案

It doesn't, at least in OpenJDK. 它至少在OpenJDK中没有。

However, I don't see anything in its contract that would forbid the existence of such a buffer, as long as it was transparent to the user. 但是，我没有在合同中看到任何禁止存在这种缓冲区的内容，只要它对用户是透明的。 It would not make much sense, though, given that BufferedInputStream exists for that purpose. 但是，考虑到为此目的存在BufferedInputStream ，这没有多大意义。

The SO question you mention deals specifically with InputStreamReader and BufferedReader instead of *Stream classes you talk about. 你提到的SO问题专门用于处理InputStreamReader和BufferedReader而不是你所谈论的* Stream类。 It even mentions the default buffer size of BufferedReader. 它甚至提到了BufferedReader的默认缓冲区大小。

I know it is a long post, but you should read it all instead of forking it to another question after reading its first sentence. 我知道这是一个很长的帖子，但你应该阅读所有内容，而不是在阅读完第一句话之后将其分解为另一个问题。

To give you an answer, looking at the link provided by Matt Ball , apparently not . 为了给你答案，看看Matt Ball提供的链接，显然不是。