cn.novelweb.tool.upload.fastdfs.utils.BytesUtil Maven / Gradle / Ivy
package cn.novelweb.tool.upload.fastdfs.utils;
import java.nio.charset.Charset;
import java.util.Arrays;
/**
* Java与C服务端数据交换时byte数组与int,long转换的工具类
* 2016/11/20 1:14
*
* @author LiZW
**/
public class BytesUtil {
/**
* long convert to buff (big-endian)
*
* @param n long number
* @return 8 bytes buff
*/
public static byte[] long2buff(long n) {
byte[] bs;
bs = new byte[8];
bs[0] = (byte) ((n >> 56) & 0xFF);
bs[1] = (byte) ((n >> 48) & 0xFF);
bs[2] = (byte) ((n >> 40) & 0xFF);
bs[3] = (byte) ((n >> 32) & 0xFF);
bs[4] = (byte) ((n >> 24) & 0xFF);
bs[5] = (byte) ((n >> 16) & 0xFF);
bs[6] = (byte) ((n >> 8) & 0xFF);
bs[7] = (byte) (n & 0xFF);
return bs;
}
/**
* buff convert to long
*
* @param bs the buffer (big-endian)
* @param offset the start position based 0
* @return long number
*/
public static long buff2long(byte[] bs, int offset) {
return (((long) (bs[offset] >= 0 ? bs[offset] : 256 + bs[offset])) << 56)
| (((long) (bs[offset + 1] >= 0 ? bs[offset + 1] : 256 + bs[offset + 1])) << 48)
| (((long) (bs[offset + 2] >= 0 ? bs[offset + 2] : 256 + bs[offset + 2])) << 40)
| (((long) (bs[offset + 3] >= 0 ? bs[offset + 3] : 256 + bs[offset + 3])) << 32)
| (((long) (bs[offset + 4] >= 0 ? bs[offset + 4] : 256 + bs[offset + 4])) << 24)
| (((long) (bs[offset + 5] >= 0 ? bs[offset + 5] : 256 + bs[offset + 5])) << 16)
| (((long) (bs[offset + 6] >= 0 ? bs[offset + 6] : 256 + bs[offset + 6])) << 8)
| (bs[offset + 7] >= 0 ? bs[offset + 7] : 256 + bs[offset + 7]);
}
/**
* buff convert to int
*
* @param bs the buffer (big-endian)
* @param offset the start position based 0
* @return int number
*/
public static int buff2int(byte[] bs, int offset) {
return ((bs[offset] >= 0 ? bs[offset] : 256 + bs[offset]) << 24)
| ((bs[offset + 1] >= 0 ? bs[offset + 1] : 256 + bs[offset + 1]) << 16)
| ((bs[offset + 2] >= 0 ? bs[offset + 2] : 256 + bs[offset + 2]) << 8)
| (bs[offset + 3] >= 0 ? bs[offset + 3] : 256 + bs[offset + 3]);
}
/**
* 将String转换为byte
*/
public static byte[] objString2Byte(String value, int max, Charset charset) {
byte[] fullContentBytes = new byte[max];
// 填充默认值
Arrays.fill(fullContentBytes, (byte) 0);
if (null == value) {
return fullContentBytes;
}
// 获取byte
byte[] realContent = value.getBytes(charset);
int length;
if (realContent.length <= max) {
length = realContent.length;
} else {
length = max;
}
// 复制数值
System.arraycopy(realContent, 0, fullContentBytes, 0, length);
return fullContentBytes;
}
/**
* 将String转换为byte
*/
public static byte[] objString2Byte(String value, Charset charset) {
if (null == value) {
return null;
}
// 获取byte
return value.getBytes(charset);
}
}