FileInputStream和BufferedInputStream在Java中的区别是什么？[关闭]

Question

Java中FileInputStream和BufferedInputStream的区别是什么？

Answer 1

1,2c1,2
< public class FileInputStream
< extends InputStream
---
> public class BufferedInputStream
> extends FilterInputStream
4,8c4,11
< A FileInputStream obtains input bytes from a file in a file system. What files
< are available depends on the host environment.
<
< FileInputStream is meant for reading streams of raw bytes such as image data.
< For reading streams of characters, consider using FileReader.
---
> A BufferedInputStream adds functionality to another input stream-namely, the
> ability to buffer the input and to support the mark and reset methods. When the
> BufferedInputStream is created, an internal buffer array is created. As bytes
> from the stream are read or skipped, the internal buffer is refilled as
> necessary from the contained input stream, many bytes at a time. The mark
> operation remembers a point in the input stream and the reset operation causes
> all the bytes read since the most recent mark operation to be reread before new
> bytes are taken from the contained input stream.

Answer 2

你必须google或阅读Javadocs，

public class FileInputStream
extends InputStream

FileInputStream从文件系统中的文件获取输入字节。哪些文件可用取决于主机环境。

FileInputStream用于读取原始字节流，如图像数据。要读取字符流，请考虑使用FileReader。

更多详情：https://docs.oracle.com/javase/7/docs/api/java/io/FileInputStream.html.

public class BufferedInputStream
extends FilterInputStream

BufferedInputStream为另一个输入流添加了功能，即缓冲输入并支持标记和重置方法的能力。创建BufferedInputStream时，会创建一个内部缓冲区数组。当从流中读取或跳过字节时，内部缓冲区根据需要从包含的输入流中重新填充，一次填充许多字节。标记操作记住输入流中的一个点，重置操作导致自最近标记操作以来读取的所有字节在从包含的输入流中获取新字节之前被重读。

欲知详情https://docs.oracle.com/javase/7/docs/api/java/io/BufferedInputStream.html.

Answer 3

主要区别：

>

BufferedInputStream从另一个InputStream读取，而FileInputStream从文件¹读取。

实际上，这意味着每次调用FileInputStream.read（）都会执行syscall（昂贵的）...而大多数调用BufferedInputStream.read（）都会从缓冲区返回数据。简而言之，如果您正在进行“小”读取，将一个BufferedInputStream放入流堆栈将提高性能。

>

对于大多数目的/用例，这是所有相关的。

还有一些其他的事情（如标记/重置/跳过），但这些都是相当专业的。。。

有关更详细的信息，请阅读javadocs...和源代码。

^{1-或者更准确地说，来自某个对象，该对象1）在操作系统的“文件系统”命名空间中具有名称，2）操作系统允许您以字节序列的形式读取。这可能包括设备、命名管道和其他可能不被认为是“文件”的其他东西。还值得注意的是，有些东西使用FileInputStream绝对无法读取}