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int、char、double與byte相互轉(zhuǎn)換的程序

轉(zhuǎn)載  http://www.matrix.org.cn/thread.shtml?forum_id=19&view_id=919
int、char、double與byte相互轉(zhuǎn)換的程序
//整數(shù)到字節(jié)數(shù)組的轉(zhuǎn)換
  public static byte[] intToByte(int number) {
    int temp = number;
    byte[] b=new byte[4];
    for (int i=b.length-1;i>-1;i--){
      b[i] = new Integer(temp&0xff).byteValue();      //將最高位保存在最低位
      temp = temp >> 8;       //向右移8位
    }
    return b;
  }

  //字節(jié)數(shù)組到整數(shù)的轉(zhuǎn)換
  public static int byteToInt(byte[] b) {
    int s = 0;
    for (int i = 0; i < 3; i++) {
      if (b[i] >= 0)
        s = s + b[i];
      else


        s = s + 256 + b[i];
      s = s * 256;
    }
    if (b[3] >= 0)       //最后一個(gè)之所以不乘，是因?yàn)榭赡軙?huì)溢出
      s = s + b[3];
    else
      s = s + 256 + b[3];
    return s;
  }

  //字符到字節(jié)轉(zhuǎn)換
  public static byte[] charToByte(char ch){
    int temp=(int)ch;
    byte[] b=new byte[2];
    for (int i=b.length-1;i>-1;i--){
      b[i] = new Integer(temp&0xff).byteValue();      //將最高位保存在最低位
      temp = temp >> 8;       //向右移8位
    }
    return b;
  }

  //字節(jié)到字符轉(zhuǎn)換


  public static char byteToChar(byte[] b){
    int s=0;
    if(b[0]>0)
      s+=b[0];
    else
      s+=256+b[0];
    s*=256;
    if(b[1]>0)
      s+=b[1];
    else
      s+=256+b[1];
    char ch=(char)s;
    return ch;
  }

  //浮點(diǎn)到字節(jié)轉(zhuǎn)換
  public static byte[] doubleToByte(double d){
    byte[] b=new byte[8];
    long l=Double.doubleToLongBits(d);
    for(int i=0;i<b.length;i++){
      b[i]=new Long(l).byteValue();
      l=l>>8;


    }
    return b;
  }

  //字節(jié)到浮點(diǎn)轉(zhuǎn)換
  public static double byteToDouble(byte[] b){
    long l;

    l=b[0];
    l&=0xff;
    l|=((long)b[1]<<8);
    l&=0xffff;
    l|=((long)b[2]<<16);
    l&=0xffffff;
    l|=((long)b[3]<<24);
    l&=0xffffffffl;
    l|=((long)b[4]<<32);
    l&=0xffffffffffl;

    l|=((long)b[5]<<40);
    l&=0xffffffffffffl;
    l|=((long)b[6]<<48);


    l|=((long)b[7]<<56);
    return Double.longBitsToDouble(l);
  }

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posted on 2005-11-25 12:42 春雷的博客 閱讀(920) 評(píng)論(0)  編輯  收藏 所屬分類: 技術(shù)