Java unsigned byte[2] 到 int？
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Java unsigned byte[2] to int?
提问by Eric Fossum
All I need to do is convert an unsigned two byte array to an integer. I know, I know, Java doesn't have unsigned data types, but my numbers are in pretend unsigned bytes.
我需要做的就是将一个无符号的两字节数组转换为一个整数。我知道，我知道，Java 没有无符号数据类型，但我的数字是假装无符号字节。
byte[] b = {(byte)0x88, (byte)0xb8}; // aka 35000
int i = (byte)b[0] << 8 | (byte)b[1];
Problem is that doesn't convert properly, because it thinks those are signed bytes... How do I convert it back to an int?
问题是不能正确转换，因为它认为那些是有符号字节......我如何将它转换回一个整数？
回答by rgettman
There are no unsigned numbers in Java, bytes or ints or anything else. When the bytes are converted to intprior to being bitshifted, they are sign-extended, i.e. 0x88=> 0xFFFFFF88. You need to mask out what you don't need.
Java 中没有无符号数、字节或整数或其他任何东西。当字节int在移位之前被转换为 时，它们被符号扩展，即0x88=> 0xFFFFFF88。你需要屏蔽掉你不需要的东西。
Try this
试试这个
int i = ((b[0] << 8) & 0x0000ff00) | (b[1] & 0x000000ff);
and you will get 35000.
你会得到 35000。
回答by Peter Lawrey
You can use
您可以使用
int i = ((b[0] & 0xFF) << 8) | (b[1] & 0xFF);
or
或者
int i = ByteBuffer.wrap(b).getChar();
or
或者
int i = ByteBuffer.wrap(b).getShort() & 0xFFFF;
