Java I/O method types

Question

Quick theoretical question:

Why are java Input/Output methods of Integer type?

For example:

InputStream
int read()
int read(byte cbuf[])
int read(byte cbuf[], int offset, int length)

Answer 1

第一个以int形式读取无符号字节（由于Java的字节是有符号的，因此您需要更大的数据类型来保存0-255之间的值），后两个方法返回读取的字节数。

Answer 2

Why are java Input/Output methods of Integer type?

They aren't. They are of int type.

The reason read() returns an int is so that it can return the out-of-band value -1, meaning end of stream.

The reason the other read() methods return int is to indicate the number of bytes received, or -1 indicating end of stream.