浅谈二进制、十进制、十六进制、字符串之间的相互转换

/*
   * 字节转10进制
   */
  public static int byte2Int(byte b){
    int r = (int) b;
    return r;
  }

/*
   * 10进制转字节
   */
  public static byte int2Byte(int i){
    byte r = (byte) i;
    return r;
  }

/*
   * 字节数组转16进制字符串
   */
  public static String bytes2HexString(byte[] b) {
    String r = "";
    
    for (int i = 0; i < b.length; i++) {
      String hex = Integer.toHexString(b[i] & 0xFF);
      if (hex.length() == 1) {
        hex = '0' + hex;
      }
      r += hex.toUpperCase();
    }
    
    return r;
  }

/*
   * 字符转换为字节
   */
  private static byte charToByte(char c) {
    return (byte) "0123456789ABCDEF".indexOf(c);
   }
  
  /*
   * 16进制字符串转字节数组
   */
  public static byte[] hexString2Bytes(String hex) {
      
      if ((hex == null) || (hex.equals(""))){
        return null;
      }
      else if (hex.length()%2 != 0){
        return null;
      }
      else{        
        hex = hex.toUpperCase();
        int len = hex.length()/2;
        byte[] b = new byte[len];
        char[] hc = hex.toCharArray();
        for (int i=0; i<len; i++){
          int p=2*i;
          b[i] = (byte) (charToByte(hc[p]) << 4 | charToByte(hc[p+1]));
        }
       return b;
      }      
      
  }

/*
   * 字节数组转字符串
   */
  public static String bytes2String(byte[] b) throws Exception {
    String r = new String (b,"UTF-8");    
    return r;
  }

/*
   * 字符串转字节数组
   */
  public static byte[] string2Bytes(String s){
    byte[] r = s.getBytes();
    return r;
  }

/*
   * 16进制字符串转字符串
   */
  public static String hex2String(String hex) throws Exception{
    String r = bytes2String(hexString2Bytes(hex));    
    return r;
  }

/*
   * 字符串转16进制字符串
   */
  public static String string2HexString(String s) throws Exception{
    String r = bytes2HexString(string2Bytes(s));    
    return r;
  }

public static void main(String[] args) throws Exception{    
    byte b1 = (byte) 45;
    System.out.println("1.字节转10进制:" + byte2Int(b1));
    
    int i = 89;
    System.out.println("2.10进制转字节:" + int2Byte(i));
    
    byte[] b2 = new byte[]{(byte)0xFF, (byte)0x5F, (byte)0x6, (byte)0x5A};
    System.out.println("3.字节数组转16进制字符串:" + bytes2HexString(b2));
    
    String s1 = new String("1DA47C");
    System.out.println("4.16进制字符串转字节数组:" + Arrays.toString(hexString2Bytes(s1)));
    
    System.out.println("5.字节数组转字符串:" + bytes2String(b2));
    
    System.out.println("6.字符串转字节数组:" + Arrays.toString(string2Bytes(s1)));
    
    System.out.println("7.16进制字符串转字符串:" + hex2String(s1));
    
    String s2 = new String("Hello!");
    System.out.println("8.字符串转16进制字符串:" + string2HexString(s2));
  }

1.字节转10进制:45
2.10进制转字节:89
3.字节数组转16进制字符串:FF5F065A
4.16进制字符串转字节数组:[29, -92, 124]
5.字节数组转字符串:?_Z
6.字符串转字节数组:[49, 68, 65, 52, 55, 67]
7.16进制字符串转字符串:?|
8.字符串转16进制字符串:48656C6C6F21