参考：https://www.chenxublog.com/2020/03/08/c-fast-convert-hex-char-array.html

void char_to_hex(char *src, int len, char *des)
{
    char hex_table[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
    while (len--)
    {
        *(des++) = hex_table[(*src) >> 4];
        *(des++) = hex_table[*(src++) & 0x0f];
    }
}

Java中String字符串转换十六进制Hex类型

今天我们说一下Java中 String字符串转换为Hex十六进制字符串、byte[]字节数组转换Hex十六进制字符串。
好，接下来代码走起来-------->

1、字符串转换为十六进制字符串

public static String stringToHexString(String s) {  
            String str = "";  
            for (int i = 0; i < s.length(); i++) {  
                int ch = s.charAt(i);  
                String s4 = Integer.toHexString(ch);  
                str = str + s4;  
            }  
            return str;  
} 

2、十六进制字符串转换为字符串

public static String hexStringToString(String s) {  
            if (s == null || s.equals("")) {  
                return null;  
            }  
            s = s.replace(" ", "");  
            byte[] baKeyword = new byte[s.length() / 2];  
            for (int i = 0; i < baKeyword.length; i++) {  
                try {  
                    baKeyword[i] = (byte) (0xff & Integer.parseInt(  
                            s.substring(i * 2, i * 2 + 2), 16));  
                } catch (Exception e) {  
                    e.printStackTrace();  
                }  
            }  
            try {  
                s = new String(baKeyword, "gbk");  
                new String();  
            } catch (Exception e1) {  
                e1.printStackTrace();  
            }  
            return s;  
}

3、十六进制字符串转换为byte[]数组

public static byte[] hexStringToByteArray(String s) {
          int len = s.length();
          byte[] b = new byte[len / 2];
          for (int i = 0; i < len; i += 2) {
              // 两位一组，表示一个字节,把这样表示的16进制字符串，还原成一个字节
              b[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character
                      .digit(s.charAt(i + 1), 16));
          }
          return b;
}

4、byte[]字节数组转十六进制字符串

public static final String bytesToHexString(byte[] bArray) {
          StringBuffer sb = new StringBuffer(bArray.length);
          String sTemp;
          for (int i = 0; i < bArray.length; i++) {
           sTemp = Integer.toHexString(0xFF & bArray[i]);
           if (sTemp.length() < 2)
            sb.append(0);
           sb.append(sTemp.toUpperCase());
          }
          return sb.toString();
}