byteArray转换为double,int

1. /*将int转为低字节在前，高字节在后的byte数组
2.  
   b[0] = 11111111(0xff) & 01100001
3.  
   b[1] = 11111111(0xff) & (n >> 8)00000000
4.  
   b[2] = 11111111(0xff) & (n >> 8)00000000
5.  
   b[3] = 11111111(0xff) & (n >> 8)00000000
6.  
   */
7.  
   public byte[] IntToByteArray(int n) {
8.  
   byte[] b = new byte[4];
9.  
   b[0] = (byte) (n & 0xff);
10.  
    b[1] = (byte) (n >> 8 & 0xff);
11.  
    b[2] = (byte) (n >> 16 & 0xff);
12.  
    b[3] = (byte) (n >> 24 & 0xff);
13.  
    return b;
14.  
    }
15.  
    //将低字节在前转为int，高字节在后的byte数组(与IntToByteArray1想对应)
16.  
    public int ByteArrayToInt(byte[] bArr) {
17.  
    if(bArr.length!=4){
18.  
    return -1;
19.  
    }
20.  
    return (int) ((((bArr[3] & 0xff) << 24)
21.  
    | ((bArr[2] & 0xff) << 16)
22.  
    | ((bArr[1] & 0xff) << 8)
23.  
    | ((bArr[0] & 0xff) << 0)));
24.  
    }
25. 1. public static byte[] double2Bytes(double d) {
    2.  
       long value = Double.doubleToRawLongBits(d);
    3.  
       byte[] byteRet = new byte[8];
    4.  
       for (int i = 0; i < 8; i++) {
    5.  
       byteRet[i] = (byte) ((value >> 8 * i) & 0xff);
    6.  
       }
    7.  
       return byteRet;
    8.  
       }

        

       1. public static double bytes2Double(byte[] arr) {
       2.  
          long value = 0;
       3.  
          for (int i = 0; i < 8; i++) {
       4.  
          value |= ((long) (arr[i] & 0xff)) << (8 * i);
       5.  
          }
       6.  
          return Double.longBitsToDouble(value);
       7.  
          }