[Java] Display the bit string stored in the byte type variable on the console

Bit string stored in byte

Java's byte type stores 8 bits (= 1 byte) of data. The bit string (binary number) stored in byte is expressed in hexadecimal and decimal as follows.

Display the bit string on the console

This section describes how to display in binary notation and how to display in hexadecimal notation.

--Binary notation

1:  byte b = 10;
2:  int i = Byte.toUnsignedInt(b); //Unsigned conversion
3:  String str = Integer.toBinaryString(i); //Get binary string
4:  str = String.format("%8s", str).replace(' ', '0'); //0 padding
5:  System.out.println(str);

--Hexary notation

1:  byte b = 10;
2:  System.out.print(String.format("%02X", b));

The output results of each are as follows.

Binary number: 00001010
Hexagon: 0A

If you compare the output methods, you can see that the binary notation requires various conversions.

What kind of conversion is being performed in binary notation?

I will explain what kind of conversion is being performed in binary notation. First from the second line.

2nd line: Convert from byte type to ʻint` type

2:  int i = Byte.toUnsignedInt(b); //Unsigned conversion

At this time, the point is that unsigned conversion is performed. The reason is that the upper 24 bits of the int type are set to 0.

Line 3: Get the binary string (bit string) of a ʻint` type variable

3:  String str = Integer.toBinaryString(i); //Get binary string

At this time, the high-order 0 is ignored. This is why we were doing unsigned conversions.

4th line: 0 padding the acquired character string

4:  str = String.format("%8s", str).replace(' ', '0'); //0 padding

Specifically, after padding with whitespace using a formatted string, the whitespace is replaceed to 0.

Summary

When I was checking the operation of the program, I suddenly wanted to check the contents of byte [], and when I searched for a method, I struggled unexpectedly, so I left a memo on how to realize it. It's a small story, but I hope it helps someone.