C的无符号数据类型int,short,byte 转为 Java对应的数据long,char,short

从网络中读取C的无符号int,short,byte字节数组，相应转换成java的long,char,short

	short anUnsignedByte = 0;
	char anUnsignedShort = 0;
	long anUnsignedInt = 0;
        int firstByte = 0;
        int secondByte = 0;
        int thirdByte = 0;
        int fourthByte = 0;

	byte buf[] = getNetData();//如:读网络字节数据
	int index = 0;	
        firstByte = (0x000000FF & ((int)buf[index]))
	index++;
	anUnsignedByte = (short)firstByte;

        firstByte = (0x000000FF & ((int)buf[index]))
        secondByte = (0x000000FF & ((int)buf[index+1]))
	index = index+2;
	anUnsignedShort  = (char) (firstByte << 8 | secondByte);

        firstByte = (0x000000FF & ((int)buf[index]))
        secondByte = (0x000000FF & ((int)buf[index+1]))
        thirdByte = (0x000000FF & ((int)buf[index+2]))
        fourthByte = (0x000000FF & ((int)buf[index+3]))
        index = index+4;
	anUnsignedInt  = ((long) (firstByte << 24
	                | secondByte << 16
                        | thirdByte << 8
                        | fourthByte))
                       & 0xFFFFFFFFL;