short、int、long与byte之间的转换工具类

/**

* 各基础类型与byte之间的转换

* @author shanl

*

*/

public class Utility {

/**

* 将short转成byte[2]

* @param a

* @return

*/

public static byte[] short2Byte(short a){

byte[] b = new byte[2];

b[0] = (byte) (a >> 8);

b[1] = (byte) (a);

return b;

}

/**

* 将short转成byte[2]

* @param a

* @param b

* @param offset b中的偏移量

*/

public static void short2Byte(short a, byte[] b, int offset){

b[offset] = (byte) (a >> 8);

b[offset+1] = (byte) (a);

}

/**

* 将byte[2]转换成short

* @param b

* @return

*/

public static short byte2Short(byte[] b){

return (short) (((b[0] & 0xff) << 8) | (b[1] & 0xff));

}

/**

* 将byte[2]转换成short

* @param b

* @param offset

* @return

*/

public static short byte2Short(byte[] b, int offset){

return (short) (((b[offset] & 0xff) << 8) | (b[offset+1] & 0xff));

}

/**

* long转byte[8]

*

* @param a

* @param b

* @param offset

* b的偏移量

*/

public static void long2Byte(long a, byte[] b, int offset) {

b[offset + 0] = (byte) (a >> 56);

b[offset + 1] = (byte) (a >> 48);

b[offset + 2] = (byte) (a >> 40);

b[offset + 3] = (byte) (a >> 32);

b[offset + 4] = (byte) (a >> 24);

b[offset + 5] = (byte) (a >> 16);

b[offset + 6] = (byte) (a >> 8);

b[offset + 7] = (byte) (a);

}

/**

* byte[8]转long

*

* @param b

* @param offset

* b的偏移量

* @return

*/

public static long byte2Long(byte[] b, int offset) {

return ((((long) b[offset + 0] & 0xff) << 56)

| (((long) b[offset + 1] & 0xff) << 48)

| (((long) b[offset + 2] & 0xff) << 40)

| (((long) b[offset + 3] & 0xff) << 32)

| (((long) b[offset + 4] & 0xff) << 24)

| (((long) b[offset + 5] & 0xff) << 16)

| (((long) b[offset + 6] & 0xff) << 8)

| (((long) b[offset + 7] & 0xff) << 0));

}

/**

* byte[8]转long

*

* @param b

* @return

*/

public static long byte2Long(byte[] b) {

return

((b[0]&0xff)<<56)|

((b[1]&0xff)<<48)|

((b[2]&0xff)<<40)|

((b[3]&0xff)<<32)|

((b[4]&0xff)<<24)|

((b[5]&0xff)<<16)|

((b[6]&0xff)<<8)|

(b[7]&0xff);

}

/**

* long转byte[8]

*

* @param a

* @return

*/

public static byte[] long2Byte(long a) {

byte[] b = new byte[4 * 2];

b[0] = (byte) (a >> 56);

b[1] = (byte) (a >> 48);

b[2] = (byte) (a >> 40);

b[3] = (byte) (a >> 32);

b[4] = (byte) (a >> 24);

b[5] = (byte) (a >> 16);

b[6] = (byte) (a >> 8);

b[7] = (byte) (a >> 0);

return b;

}

/**

* byte数组转int

*

* @param b

* @return

*/

public static int byte2Int(byte[] b) {

return ((b[0] & 0xff) << 24) | ((b[1] & 0xff) << 16)

| ((b[2] & 0xff) << 8) | (b[3] & 0xff);

}

/**

* byte数组转int

*

* @param b

* @param offset

* @return

*/

public static int byte2Int(byte[] b, int offset) {

return ((b[offset++] & 0xff) << 24) | ((b[offset++] & 0xff) << 16)

| ((b[offset++] & 0xff) << 8) | (b[offset++] & 0xff);

}

/**

* int转byte数组

*

* @param a

* @return

*/

public static byte[] int2Byte(int a) {

byte[] b = new byte[4];

b[0] = (byte) (a >> 24);

b[1] = (byte) (a >> 16);

b[2] = (byte) (a >> 8);

b[3] = (byte) (a);

return b;

}

/**

* int转byte数组

*

* @param a

* @param b

* @param offset

* @return

*/

public static void int2Byte(int a, byte[] b, int offset) {

b[offset++] = (byte) (a >> 24);

b[offset++] = (byte) (a >> 16);

b[offset++] = (byte) (a >> 8);

b[offset++] = (byte) (a);

}

}