我试图转换一个无符号的有符号字节。问题是我接收的数据是无符号的，Java不支持无符号字节，所以当它读取数据时，它将其视为有符号的。
我尝试通过下面的解决方案转换它，我从Stack Overflow。
public static int unsignedToBytes(byte a)
{
int b = a & 0xFF;
return b;
}
但是当它再次以字节为单位转换时，我得到了相同的带符号数据。我试图使用此数据作为参数的Java函数，只接受一个字节作为参数，所以我不能使用任何其他数据类型。我该如何解决这个问题?
当前回答
如果你认为你正在寻找这样的东西。
public static char toUnsigned(byte b) {
return (char) (b >= 0 ? b : 256 + b);
}
其他回答
如果您想在Java中使用无符号字节，只需从感兴趣的数字中减去256。它将生成带有负值的2的补数，这是所需的无符号字节数。
例子:
int speed = 255; //Integer with the desired byte value
byte speed_unsigned = (byte)(speed-256);
//This will be represented in two's complement so its binary value will be 1111 1111
//which is the unsigned byte we desire.
在使用leJOS编程NXT块时，您需要使用这种肮脏的技巧。
顺便说一句，如果你想打印出来，你可以说
byte b = 255;
System.out.println((b < 0 ? 256 + b : b));
由于Java中的限制，无符号字节在当前的数据类型格式中几乎是不可能的。你可以为你要实现的东西使用其他语言的其他库，然后你可以使用JNI调用它们。
在Java中没有原始无符号字节。通常的做法是将其转换为更大的类型:
int anUnsignedByte = (int) aSignedByte & 0xff;
我试图使用此数据作为参数的Java函数，只接受一个字节作为参数
这与函数接受一个大于2^32-1的整数并没有本质上的区别。
这听起来似乎取决于函数是如何定义和记录的;我认为有三种可能:
It may explicitly document that the function treats the byte as an unsigned value, in which case the function probably should do what you expect but would seem to be implemented wrong. For the integer case, the function would probably declare the parameter as an unsigned integer, but that is not possible for the byte case. It may document that the value for this argument must be greater than (or perhaps equal to) zero, in which case you are misusing the function (passing an out-of-range parameter), expecting it to do more than it was designed to do. With some level of debugging support you might expect the function to throw an exception or fail an assertion. The documentation may say nothing, in which case a negative parameter is, well, a negative parameter and whether that has any meaning depends on what the function does. If this is meaningless then perhaps the function should really be defined/documented as (2). If this is meaningful in an nonobvious manner (e.g. non-negative values are used to index into an array, and negative values are used to index back from the end of the array so -1 means the last element) the documentation should say what it means and I would expect that it isn't what you want it to do anyway.
