Java整型数与网络字节序byte[]数组转换关系详解

本文实例讲述了java整型数与网络字节序byte[]数组转换关系。分享给大家供大家参考，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。
}

测试程序如下：

public class byteconverttest {
  public static string byte2hex(byte[] buf)
  {
    stringbuffer strbuf = new stringbuffer();
    strbuf.append("{");
    for (byte b : buf)
    {
      if (b == 0)
      {
        strbuf.append("00");
      }
      else if (b == -1)
      {
        strbuf.append("ff");
      }
      else
      {
        string str = integer.tohexstring(b).touppercase();
        // sb.append(a);
        if (str.length() == 8)
        {
          str = str.substring(6, 8);
        }
        else if (str.length() < 2)
        {
          str = "0" + str;
        }
        strbuf.append(str);
      }
      strbuf.append(" ");
    }
    strbuf.append("}");
    return strbuf.tostring();
  }
  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 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) ));
  }
  public static int bytestoint(byte b[]) {
    return  b[3] & 0xff
        | (b[2] & 0xff) << 8
        | (b[1] & 0xff) << 16
        | (b[0] & 0xff) << 24;
  }
  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 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 byte[] shorttobytes(short n) {
    byte[] b = new byte[2];
    b[1] = (byte) ( n    & 0xff);
    b[0] = (byte) ((n >> 8) & 0xff);
    return b;
  }
  public static short bytestoshort(byte[] b){
    return (short)( b[1] & 0xff
           |(b[0] & 0xff) << 8 );
  }
  static void testshortconvert(){
    system.out.println("=================== short convert =============");
    system.out.println("byte2hex(shorttobytes((short)0x11f2))"+byte2hex(shorttobytes((short)0x11f2)));
    system.out.print("println 0x11f2:");
    system.out.println((short)0x11f2);
    system.out.println("byte2hex(shorttobytes((short)0xf1f2))"+byte2hex(shorttobytes((short)0xf1f2)));
    system.out.print("println 0xf1f2:");
    system.out.println((short)0xf1f2);
    system.out.print("println bytestoshort(shorttobytes((short)0x11f2)):");
    system.out.println((short)bytestoshort(shorttobytes((short)0x11f2)));
    system.out.print("println bytestoshort(shorttobytes((short)0xf1f2)):");
    system.out.println((short)bytestoshort(shorttobytes((short)0xf1f2)));
  }
  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 int bytestoushort(byte b[]) {
    return  b[1] & 0xff
        | (b[0] & 0xff) << 8;
  }
  static void testushortconvert(){
    system.out.println("=================== ushort convert =============");
    system.out.println("byte2hex(ushorttobytes(0x11f2))"+byte2hex(ushorttobytes(0x11f2)));
    system.out.print("println 0x11f2:");
    system.out.println(0x11f2);
    system.out.println("byte2hex(ushorttobytes(0xf1f2))"+byte2hex(ushorttobytes(0xf1f2)));
    system.out.print("println 0xf1f2:");
    system.out.println(0xf1f2);
    system.out.print("println bytestoushort(ushorttobytes(0x11f2)):");
    system.out.println(bytestoushort(ushorttobytes(0x11f2)));
    system.out.print("println bytestoushort(ushorttobytes(0xf1f2)):");
    system.out.println(bytestoushort(ushorttobytes(0xf1f2)));
  }
  public static byte[] ubytetobytes( int n ){
    byte[] b = new byte[1];
    b[0] = (byte) (n & 0xff);
    return b;
  }
  public static int bytestoubyte( byte[] array ){
    return array[0] & 0xff;
  }
  static void testubyteconvert(){
    system.out.println("=================== ubyte convert =============");
    system.out.println("byte2hex(ubytetobytes(0x1112))"+byte2hex(ubytetobytes(0x1112)));
    system.out.print("println 0x1112:");
    system.out.println(0x1112);
    system.out.println("byte2hex(ubytetobytes(0xf2))"+byte2hex(ubytetobytes(0xf2)));
    system.out.print("println 0xf2:");
    system.out.println(0xf2);
    system.out.print("println bytestoubyte(ubytetobytes(0x1112)):");
    system.out.println(bytestoubyte(ubytetobytes(0x1112)));
    system.out.print("println bytestoubyte(ubytetobytes(0xf1f2)):");
    system.out.println(bytestoubyte(ubytetobytes(0xf1f2)));
  }
  /**
   * @param args
   */
  public static void main(string[] args) {
    // todo auto-generated method stub
    byte[] array = new byte[4];
    array[3] = (byte) 0xf4;
    array[2] = 0x13;
    array[1] = 0x12;
    array[0] = 0x11;
    system.out.println("=================== integer bytes =============");
    system.out.println("the bytes is:"+byte2hex(array) );
    system.out.print("println bytestoint :");
    system.out.println( bytestoint(array));
    system.out.printf("printf bytestoint :%x\n", bytestoint(array));
    system.out.println("=================== long bytes =============");
    byte[] longbytes = new byte[8];
    longbytes[7] = (byte) 0xf7;
    longbytes[6] = (byte) 0x16;
    longbytes[5] = (byte) 0xf5;
    longbytes[4] = (byte) 0x14;
    longbytes[3] = (byte) 0xf3;
    longbytes[2] = (byte) 0x12;
    longbytes[1] = (byte) 0xf1;
    longbytes[0] = (byte) 0x10;
    system.out.println( "the bytes is:"+byte2hex(longbytes) );
    system.out.printf("printf bytestolong:%x\n",bytestolong(longbytes));
    system.out.println("=================byte to long ================");
    byte b = (byte)0xf1;
    system.out.print("println the byte:");
    system.out.println(b);
    system.out.printf("printf the byte:%x\n",b);
    long l = b;
    system.out.print("println byte to long:");
    system.out.println(l);
    system.out.printf("printf byte to long:%x\n",l);
    system.out.println("================= uint bytes ================");
    byte[] uint = new byte[4];
    uint[3] = (byte) 0xf3;
    uint[2] = (byte) 0x12;
    uint[1] = (byte) 0xf1;
    uint[0] = (byte) 0xff;
    system.out.println( "the bytes is:"+byte2hex(uint) );
    system.out.printf("printf bytestouint:%x\n",bytestouint(uint));
    system.out.print("println bytestouint:");
    system.out.println(bytestouint(uint));
    system.out.println("byte2hex(uinttobytes(0x11f2f3f4f5f6f7f8l)):"+byte2hex(uinttobytes(0x11f2f3f4f5f6f7f8l)));
    system.out.println("===============long integer==============");
    system.out.print("println 0x11f2f3f4f5f6f7f8l:");
    system.out.println(0x11f2f3f4f5f6f7f8l);
    system.out.printf("printf 0x11f2f3f4f5f6f7f8l:%x\n",0x11f2f3f4f5f6f7f8l);
    system.out.println("println byte2hex(longtobytes(0x11f2f3f4f5f6f7f8l))"+byte2hex(longtobytes(0x11f2f3f4f5f6f7f8l)));
    // 注意，下面的这行，并不能获得正确的uint。
    system.out.printf("printf bytestouint(longtobytes(0x11f2f3f4f5f6f7f8l):%x\n",bytestouint(longtobytes(0x11f2f3f4f5f6f7f8l)));
    system.out.println("===============bytestolong(longtobytes())==============");
    system.out.println(bytestolong(longtobytes(0x11f2f3f4f5f6f7f8l)));
    system.out.printf("%x\n",bytestolong(longtobytes(0x11f2f3f4f5f6f7f8l)));
    testshortconvert();
    testushortconvert();
    testubyteconvert();
  }
}

更多关于java相关内容感兴趣的读者可查看本站专题：《java字符与字符串操作技巧总结》、《java数学运算技巧总结》、《java数据结构与算法教程》、《java操作dom节点技巧总结》和《java数组操作技巧总结》

希望本文所述对大家java程序设计有所帮助。