版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/u014252478/article/details/82854778
1、long与byte之间的转换
public class Utilities {
public static byte[] int2Bytes(int num) {
byte[] byteNum = new byte[4];
for (int ix = 0; ix < 4; ++ix) {
int offset = 32 - (ix + 1) * 8;
byteNum[ix] = (byte) ((num >> offset) & 0xff);
}
return byteNum;
}
public static int bytes2Int(byte[] byteNum) {
int num = 0;
for (int ix = 0; ix < 4; ++ix) {
num <<= 8;
num |= (byteNum[ix] & 0xff);
}
return num;
}
public static byte int2OneByte(int num) {
return (byte) (num & 0x000000ff);
}
public static int oneByte2Int(byte byteNum) {
return byteNum > 0 ? byteNum : (128 + (128 + byteNum));
}
public static byte[] long2Bytes(long num) {
byte[] byteNum = new byte[8];
for (int ix = 0; ix < 8; ++ix) {
int offset = 64 - (ix + 1) * 8;
byteNum[ix] = (byte) ((num >> offset) & 0xff);
}
return byteNum;
}
public static long bytes2Long(byte[] byteNum) {
long num = 0;
for (int ix = 0; ix < 8; ++ix) {
num <<= 8;
num |= (byteNum[ix] & 0xff);
}
return num;
}
public static void main(String[] args) {
int num = 129;
System.out.println("测试的int值为:" + num);
byte[] int2bytes = Utilities.int2Bytes(num);
System.out.printf("int转成bytes: ");
for (int i = 0; i < 4; ++i) {
System.out.print(int2bytes[i] + " ");
}
System.out.println();
int bytes2int = Utilities.bytes2Int(int2bytes);
System.out.println("bytes转行成int: " + bytes2int);
byte int2OneByte = Utilities.int2OneByte(num);
System.out.println("int转行成one byte: " + int2OneByte);
int oneByte2Int = Utilities.oneByte2Int(int2OneByte);
System.out.println("one byte转行成int: " + oneByte2Int);
System.out.println();
long longNum = 100000;
System.out.println("测试的long值为:" + longNum);
byte[] long2Bytes = Utilities.long2Bytes(longNum);
System.out.printf("long转行成bytes: ");
for (int ix = 0; ix < long2Bytes.length; ++ix) {
System.out.print(long2Bytes[ix] + " ");
}
System.out.println();
long bytes2Long = Utilities.bytes2Long(long2Bytes);
System.out.println("bytes转行成long: " + bytes2Long);
}
}
2、int和byte转换
package com.chargedot.util;
/**
* @Author:caoj
* @Description:
* @Data:Created in 2018/5/14
*/
public class ByteUtil {
public static int bytesToInt(byte[] data, int pos, int len) {
int value = 0;
for (int i = len - 1; i >= 0; i--) {
int shift = i * 8;
value += (data[pos + i] & 0x000000FF) << shift;
}
return value;
}
public static int byte2int(byte[] res) {
int targets = (res[0] & 0xff) | ((res[1] << 8) & 0xff00) // | 表示安位或
| ((res[2] << 24) >>> 8) | (res[3] << 24);
return targets;
}
public static void fillBytes(byte[] dst, int pos, int value, int len) {
for (int i = 0; i < len; i++) {
dst[pos + i] = (byte) (value & 0xff);
value = (value >> 8);
}
}
public static void fillBytes(byte[] dst, int pos, String value) {
for (int i = 0; i < value.length(); i++) {
dst[pos + i] = (byte) (value.charAt(i) & 0xff);
}
}
public static byte[] intToBytes(int value) {
byte[] b = new byte[4];
b[0] = (byte) (value & 0xff);
b[1] = (byte) (value >> 8 & 0xff);
b[2] = (byte) (value >> 16 & 0xff);
b[3] = (byte) (value >> 24 & 0xff);
return b;
}
public static byte[] intToBytes3(int value) {
byte[] b = new byte[3];
b[0] = (byte) (value & 0xff);
b[1] = (byte) (value >> 8 & 0xff);
b[2] = (byte) (value >> 16 & 0xff);
return b;
}
public static byte[] toHH2(int n) {
byte[] b = new byte[2];
b[0] = (byte) (n & 0xff);
b[1] = (byte) (n >> 8 & 0xff);
return b;
}
//10进制转16进制字符串
public static String decimalToHex(int decimal) {
String hex = "";
while(decimal != 0) {
int hexValue = decimal % 16;
hex = toHexChar(hexValue) + hex;
decimal = decimal / 16;
}
return hex;
}
//将0~15的十进制数转换成0~F的十六进制数
public static char toHexChar(int hexValue) {
if(hexValue <= 9 && hexValue >= 0)
return (char)(hexValue + '0');
else
return (char)(hexValue - 10 + 'A');
}
}