Java整型数与网络字节序byte[]数组转换关系详解

2019-11-26 11:32:38

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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》

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