int、char、double与byte相互转换

 

//整数到字节数组的转换 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(); //将最高位保存在最低位 temp = temp >> 8; //向右移8位 } return b; } //字节数组到整数的转换 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) //最后一个之所以不乘，是因为可能会溢出 s = s + b[3]; else s = s + 256 + b[3]; return s; } //字符到字节转换 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(); //将最高位保存在最低位 temp = temp >> 8; //向右移8位 } return b; } //字节到字符转换 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; } //浮点到字节转换 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; } //字节到浮点转换 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); }