java byte数组与int，long，short，byte转换

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public class DataTypeChangeHelper {

/**

* 将一个单字节的byte转换成32位的int

*

* @param b

* byte

* @return convert result

*/

public static int unsignedByteToInt(byte b) {

return (int) b & 0xFF;

}

/**

* 将一个单字节的Byte转换成十六进制的数

*

* @param b

* byte

* @return convert result

*/

public static String byteToHex(byte b) {

int i = b & 0xFF;

return Integer.toHexString(i);

}

/**

* 将一个4byte的数组转换成32位的int

*

* @param buf

* bytes buffer

* @param byte[]中开始转换的位置

* @return convert result

*/

public static long unsigned4BytesToInt(byte[] buf, int pos) {

int firstByte = 0;

int secondByte = 0;

int thirdByte = 0;

int fourthByte = 0;

int index = pos;

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;

return ((long) (firstByte << 24 | secondByte << 16 | thirdByte << 8 | fourthByte)) & 0xFFFFFFFFL;

}

/**

* 将16位的short转换成byte数组

*

* @param s

* short

* @return byte[] 长度为2

* */

public static byte[] shortToByteArray(short s) {

byte[] targets = new byte[2];

for (int i = 0; i < 2; i++) {

int offset = (targets.length - 1 - i) * 8;

targets[i] = (byte) ((s >>> offset) & 0xff);

}

return targets;

}

/**

* 将32位整数转换成长度为4的byte数组

*

* @param s

* int

* @return byte[]

* */

public static byte[] intToByteArray(int s) {

byte[] targets = new byte[2];

for (int i = 0; i < 4; i++) {

int offset = (targets.length - 1 - i) * 8;

targets[i] = (byte) ((s >>> offset) & 0xff);

}

return targets;

}

/**

* long to byte[]

*

* @param s

* long

* @return byte[]

* */

public static byte[] longToByteArray(long s) {

byte[] targets = new byte[2];

for (int i = 0; i < 8; i++) {

int offset = (targets.length - 1 - i) * 8;

targets[i] = (byte) ((s >>> offset) & 0xff);

}

return targets;

}

/**32位int转byte[]*/

public static byte[] int2byte(int res) {

byte[] targets = new byte[4];

targets[0] = (byte) (res & 0xff);// 最低位

targets[1] = (byte) ((res >> 8) & 0xff);// 次低位

targets[2] = (byte) ((res >> 16) & 0xff);// 次高位

targets[3] = (byte) (res >>> 24);// 最高位,无符号右移。

return targets;

}

/**

* 将长度为2的byte数组转换为16位int

*

* @param res

* byte[]

* @return int

* */

public static int byte2int(byte[] res) {

// res = InversionByte(res);

// 一个byte数据左移24位变成0x??000000，再右移8位变成0x00??0000

int targets = (res[0] & 0xff) | ((res[1] << 8) & 0xff00); // | 表示安位或

return targets;

}

}