java将一个整数按字节输出,在java中将整数转换为字节

Referring to page number 79 of " Java The complete Reference" 7th edition by Herbert Schildt.

The author says : " If the integer’s value is larger than the range of a

byte, it will be reduced modulo (the remainder of an integer division by the) byte’s range".

The range of byte in java is -128 to 127. So the maximum value that fits in a byte is 128. If an integer value is assigned to a byte as shown below :

int i = 257;

byte b;

b = (byte) i;

Since 257 crosses the range 127, 257 % 127 = 3 should be stored in 'b'.

But am getting the output as 1 instead of 3.

Where have I gone wrong in understanding the concept?

解决方案

Just consider the binary representation of the numbers :

257 is represented in binary as 00000000 00000000 00000001 00000001

When you cast this 32 bits int to an 8 bits byte, you keep only the lowest 8 bits :

00000001

which is 1