如何将 Int 转换为无符号字节并返回 [英] How to Convert Int to Unsigned Byte and Back

问题描述

我需要将数字转换为无符号字节.该数字始终小于或等于 255，因此它可以容纳在一个字节中.

I need to convert a number into an unsigned byte. The number is always less than or equal to 255, and so it will fit in one byte.

我还需要将该字节转换回该数字.我将如何在 Java 中做到这一点?我已经尝试了几种方法，但都没有奏效.这是我现在要做的:

I also need to convert that byte back into that number. How would I do that in Java? I've tried several ways and none work. Here's what I'm trying to do now:

int size = 5;
// Convert size int to binary
String sizeStr = Integer.toString(size);
byte binaryByte = Byte.valueOf(sizeStr);

现在将该字节转换回数字:

and now to convert that byte back into the number:

Byte test = new Byte(binaryByte);
int msgSize = test.intValue();

显然，这不起作用.由于某种原因，它总是将数字转换为 65.有什么建议吗?

Clearly, this does not work. For some reason, it always converts the number into 65. Any suggestions?

推荐答案

一个字节总是用 Java 签名的.不过，您可以通过将其与 0xFF 进行二进制与运算来获得其无符号值:

A byte is always signed in Java. You may get its unsigned value by binary-anding it with 0xFF, though:

int i = 234;
byte b = (byte) i;
System.out.println(b); // -22
int i2 = b & 0xFF;
System.out.println(i2); // 234

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