byte[]转int，int转byte[]

b = new byte[] {0xfe,0x5a,0x11,0xfa}; u = (uint)(b[0] | b[1] << 8 |    b[2] << 16 | b[3] << 24);

b[0] = (byte)(u); b[1] = (byte)(u >> 8); b[2] = (byte)(u >> 16); b[3] = (byte)(u >> 24);