按网络字节序从字节数组中拿出8个字节拼装成一个long型

/**

* 按网络字节序从字节数组中拿出8个字节拼装成一个long型(对应c++中的long long)数据

*

* @param from

* @param fromIndex

* @return

*/

public static long getLongLongData(byte[] from, int fromIndex) {

return (((long) from[fromIndex + 4] & 0xff) << 56)

+ (((long) from[fromIndex + 5] & 0xff) << 48)

+ (((long) from[fromIndex + 6] & 0xff) << 40)

+ (((long) from[fromIndex + 7] & 0xff) << 32)

+ (((long) from[fromIndex] & 0xff) << 24)

+ (((long) from[fromIndex + 1] & 0xff) << 16)

+ (((long) from[fromIndex + 2] & 0xff) << 8)

+ ((long) from[fromIndex + 3] & 0xff);

}