利用Java在将整型数与byte[]数组进行转换-创新互联
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具体如下：
工作项目需要在java和c/c++之间进行socket通信，socket通信是以字节流或者字节包进行的，socket发送方须将数据转换为字节流或者字节包，而接收方则将字节流和字节包再转换回相应的数据类型。如果发送方和接收方都是同种语言，则一般只涉及到字节序的调整。而对于java和c/c++的通信，则情况就要复杂一些，主要是因为java中没有unsigned类型，并且java和c在某些数据类型上的长度不一致。
针对这种情况，本文整理了java数据类型和网络字节流或字节包(相当于java的byte数组)之间转换方法。实际上网上这方面的资料不少，但往往不全，甚至有些有错误，于是就花了点时间对java整型数和网络字节序的byte[]之间转换的各种情况做了一些验证和整理。整理出来的函数如下：
public class ByteConvert {
// 以下 是整型数 和 网络字节序的 byte[] 数组之间的转换
public static byte[] longToBytes(long n) {
byte[] b = new byte[8];
b[7] = (byte) (n & 0xff);
b[6] = (byte) (n >> 8 & 0xff);
b[5] = (byte) (n >> 16 & 0xff);
b[4] = (byte) (n >> 24 & 0xff);
b[3] = (byte) (n >> 32 & 0xff);
b[2] = (byte) (n >> 40 & 0xff);
b[1] = (byte) (n >> 48 & 0xff);
b[0] = (byte) (n >> 56 & 0xff);
return b;
}
public static void longToBytes( long n, byte[] array, int offset ){
array[7+offset] = (byte) (n & 0xff);
array[6+offset] = (byte) (n >> 8 & 0xff);
array[5+offset] = (byte) (n >> 16 & 0xff);
array[4+offset] = (byte) (n >> 24 & 0xff);
array[3+offset] = (byte) (n >> 32 & 0xff);
array[2+offset] = (byte) (n >> 40 & 0xff);
array[1+offset] = (byte) (n >> 48 & 0xff);
array[0+offset] = (byte) (n >> 56 & 0xff);
}
public static long bytesToLong( byte[] array )
{
return ((((long) array[ 0] & 0xff) << 56)
| (((long) array[ 1] & 0xff) << 48)
| (((long) array[ 2] & 0xff) << 40)
| (((long) array[ 3] & 0xff) << 32)
| (((long) array[ 4] & 0xff) << 24)
| (((long) array[ 5] & 0xff) << 16)
| (((long) array[ 6] & 0xff) << 8)
| (((long) array[ 7] & 0xff) << 0));
}
public static long bytesToLong( byte[] array, int offset )
{
return ((((long) array[offset + 0] & 0xff) << 56)
| (((long) array[offset + 1] & 0xff) << 48)
| (((long) array[offset + 2] & 0xff) << 40)
| (((long) array[offset + 3] & 0xff) << 32)
| (((long) array[offset + 4] & 0xff) << 24)
| (((long) array[offset + 5] & 0xff) << 16)
| (((long) array[offset + 6] & 0xff) << 8)
| (((long) array[offset + 7] & 0xff) << 0));
}
public static byte[] intToBytes(int n) {
byte[] b = new byte[4];
b[3] = (byte) (n & 0xff);
b[2] = (byte) (n >> 8 & 0xff);
b[1] = (byte) (n >> 16 & 0xff);
b[0] = (byte) (n >> 24 & 0xff);
return b;
}
public static void intToBytes( int n, byte[] array, int offset ){
array[3+offset] = (byte) (n & 0xff);
array[2+offset] = (byte) (n >> 8 & 0xff);
array[1+offset] = (byte) (n >> 16 & 0xff);
array[offset] = (byte) (n >> 24 & 0xff);
}
public static int bytesToInt(byte b[]) {
return b[3] & 0xff
| (b[2] & 0xff) << 8
| (b[1] & 0xff) << 16
| (b[0] & 0xff) << 24;
}
public static int bytesToInt(byte b[], int offset) {
return b[offset+3] & 0xff
| (b[offset+2] & 0xff) << 8
| (b[offset+1] & 0xff) << 16
| (b[offset] & 0xff) << 24;
}
public static byte[] uintToBytes( long n )
{
byte[] b = new byte[4];
b[3] = (byte) (n & 0xff);
b[2] = (byte) (n >> 8 & 0xff);
b[1] = (byte) (n >> 16 & 0xff);
b[0] = (byte) (n >> 24 & 0xff);
return b;
}
public static void uintToBytes( long n, byte[] array, int offset ){
array[3+offset] = (byte) (n );
array[2+offset] = (byte) (n >> 8 & 0xff);
array[1+offset] = (byte) (n >> 16 & 0xff);
array[offset] = (byte) (n >> 24 & 0xff);
}
public static long bytesToUint(byte[] array) {
return ((long) (array[3] & 0xff))
| ((long) (array[2] & 0xff)) << 8
| ((long) (array[1] & 0xff)) << 16
| ((long) (array[0] & 0xff)) << 24;
}
public static long bytesToUint(byte[] array, int offset) {
return ((long) (array[offset+3] & 0xff))
| ((long) (array[offset+2] & 0xff)) << 8
| ((long) (array[offset+1] & 0xff)) << 16
| ((long) (array[offset] & 0xff)) << 24;
}
public static byte[] shortToBytes(short n) {
byte[] b = new byte[2];
b[1] = (byte) ( n & 0xff);
b[0] = (byte) ((n >> 8) & 0xff);
return b;
}
public static void shortToBytes(short n, byte[] array, int offset ) {
array[offset+1] = (byte) ( n & 0xff);
array[offset] = (byte) ((n >> 8) & 0xff);
}
public static short bytesToShort(byte[] b){
return (short)( b[1] & 0xff
|(b[0] & 0xff) << 8 );
}
public static short bytesToShort(byte[] b, int offset){
return (short)( b[offset+1] & 0xff
|(b[offset] & 0xff) << 8 );
}
public static byte[] ushortToBytes(int n) {
byte[] b = new byte[2];
b[1] = (byte) ( n & 0xff);
b[0] = (byte) ((n >> 8) & 0xff);
return b;
}
public static void ushortToBytes(int n, byte[] array, int offset ) {
array[offset+1] = (byte) ( n & 0xff);
array[offset] = (byte) ((n >> 8) & 0xff);
}
public static int bytesToUshort(byte b[]) {
return b[1] & 0xff
| (b[0] & 0xff) << 8;
}
public static int bytesToUshort(byte b[], int offset) {
return b[offset+1] & 0xff
| (b[offset] & 0xff) << 8;
}
public static byte[] ubyteToBytes( int n ){
byte[] b = new byte[1];
b[0] = (byte) (n & 0xff);
return b;
}
public static void ubyteToBytes( int n, byte[] array, int offset ){
array[0] = (byte) (n & 0xff);
}
public static int bytesToUbyte( byte[] array ){
return array[0] & 0xff;
}
public static int bytesToUbyte( byte[] array, int offset ){
return array[offset] & 0xff;
}
// char 类型、 float、double 类型和 byte[] 数组之间的转换关系还需继续研究实现。
} 网页名称：利用Java在将整型数与byte[]数组进行转换-创新互联
文章出自：http://shouzuofang.com/article/dpidio.html