java int型與byte陣列之間的轉換
阿新 • • 發佈:2019-02-08
public class NumberUtil {
/**
* int整數轉換為4位元組的byte陣列
*
* @param i
* 整數
* @return byte陣列
*/
public static byte[] intToByte4(int i) {
byte[] targets = new byte[4];
targets[3] = (byte) (i & 0xFF);
targets[2] = (byte) (i >> 8 & 0xFF);
targets[1] = (byte) (i >> 16 & 0xFF);
targets[0] = (byte) (i >> 24 & 0xFF);
return targets;
}
/**
* long整數轉換為8位元組的byte陣列
*
* @param lo
* long整數
* @return byte陣列
*/
public static byte[] longToByte8 (long lo) {
byte[] targets = new byte[8];
for (int i = 0; i < 8; i++) {
int offset = (targets.length - 1 - i) * 8;
targets[i] = (byte) ((lo >>> offset) & 0xFF);
}
return targets;
}
/**
* short整數轉換為2位元組的byte陣列
*
* @param s
* short整數
* @return byte陣列
*/
public static byte[] unsignedShortToByte2(int s) {
byte[] targets = new byte[2];
targets[0] = (byte) (s >> 8 & 0xFF);
targets[1] = (byte) (s & 0xFF);
return targets;
}
/**
* byte陣列轉換為無符號short整數
*
* @param bytes
* byte陣列
* @return short整數
*/
public static int byte2ToUnsignedShort(byte[] bytes) {
return byte2ToUnsignedShort(bytes, 0);
}
/**
* byte陣列轉換為無符號short整數
*
* @param bytes
* byte陣列
* @param off
* 開始位置
* @return short整數
*/
public static int byte2ToUnsignedShort(byte[] bytes, int off) {
int high = bytes[off];
int low = bytes[off + 1];
return (high << 8 & 0xFF00) | (low & 0xFF);
}
/**
* byte陣列轉換為int整數
*
* @param bytes
* byte陣列
* @param off
* 開始位置
* @return int整數
*/
public static int byte4ToInt(byte[] bytes, int off) {
int b0 = bytes[off] & 0xFF;
int b1 = bytes[off + 1] & 0xFF;
int b2 = bytes[off + 2] & 0xFF;
int b3 = bytes[off + 3] & 0xFF;
return (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
}
}