Java bit manipulation

In the resolution of the Protocol with C, a lot of bit operations are performed. Because of the bit operation, the actual programming is not much, here is still a record.

The data from the C protocol is a 16 binary string.

The first is to convert the 16 binary string to Bytebuffer.

     Public Static bytebuffer String2buffer (String source) {        = bytebuffer.allocate (Source.length ()/2);          for (int idx = 0; idx < buffer.capacity (); idx++) {            int bytevalue = integer.parseint (sou Rce.substring (IDX * 2, IDX * 2 + 2), +);            Buffer.put ((byte) bytevalue);        }        Buffer.position (0);         return buffer;    }

The byte data is then taken from the Bytebuffer.

int flag=0; Bytebuffer buffer=nochelper.string2buffer (source);          while (Buffer.position () < buffer.limit ()) {            flag=buffer.get () & 0x0ff;        }

This is a circle, converting 16 characters into unsigned 10 digits.

Because each bit in each byte represents a different piece of information. Which takes a byte in the high 4-bit and low 4-bit time. Right SHIFT and A & operation are used.

By moving the 4-bit right, you can get a high 4-bit value.

The & operation with 0x0f, equivalent to 00001111 for the & operation, 0x0f equivalent to a mask, the height of four bits is set to 0, only the low four bits are reserved.

When judging the state of a bit in a byte, the previous practice is to use a mask. For xxxxx1xx This format data, verify that the low three bit of Foo is 1. When the value of the judgment is manipulated, the result of Foo & Integer.parseint ("00000100", 2) is judged, equal to 00000100 (4) is satisfied.

The current use of these, lest later to forget.

Java bit manipulation