/*輸入一個byte和byte[]合并為byte[]*/ 
public byte[] byteMerger(byte byte_1, byte[] byte_2) { 
 byte[] byte_3 = new byte[1 + byte_2.length]; 
 byte_3[0] = byte_1; 
 System.arraycopy(byte_2, 0, byte_3, 1, byte_2.length); 
 return byte_3; 
 } 
/*輸入一個byte[]和byte[]合并為byte[]*/ 
public byte[] byteMerger(byte[] byte_1, byte[] byte_2) { 
 byte[] byte_3 = new byte[1 + byte_2.length]; 
 byte_3[0] = byte_1; 
 System.arraycopy(byte_2, 0, byte_3, byte_1.length, byte_2.length); 
 return byte_3; 
 } 
/*輸入一個string（16進制的字符hex eg：ff）輸出為16進制的byte[]，注意輸入為小寫的hex字符串*/ 
public byte[] hexStringToByte(String hex) { 
 int len = (hex.length() / 2); 
 byte[] result = new byte[len]; 
 char[] achar = hex.toCharArray(); 
 for (int i = 0; i < len; i++) { 
  int pos = i * 2; 
  result[i] = (byte) (charToByte(achar[pos]) << 4 | charToByte(achar[pos + 1])); 
 } 
 //System.out.println(Arrays.toString(result)); 
 return result; 
 } 
 private byte charToByte(char c) { 
 //return (byte) "0123456789ABCDEF".indexOf(c); 
 return (byte) "0123456789abcdef".indexOf(c); 
 } 
/*輸入10進制數字字符串，輸出hex字符串（2位,eg: f 則輸出 0f）*/ 
String value= "100"; 
int parseInt = Integer.parseInt(value, 10); 
String hexString = Integer.toHexString(parseInt); 
  if (hexString.length() < 2) { 
  hexString = '0' + hexString; 
  } 
  header = header + hexString; 
 } 
/*輸入16進制byte[]輸出16進制字符串*/ 
 public static String byteArrayToHexStr(byte[] byteArray) { 
 if (byteArray == null) { 
  return null; 
 } 
 char[] hexArray = "0123456789ABCDEF".toCharArray(); 
 char[] hexChars = new char[byteArray.length * 2]; 
 for (int j = 0; j < byteArray.length; j++) { 
  int v = byteArray[j] & 0xFF; 
  hexChars[j * 2] = hexArray[v >>> 4]; 
  hexChars[j * 2 + 1] = hexArray[v & 0x0F]; 
 } 
 return new String(hexChars); 
 } 

let str = "http%3A%2F%2Fxxxxxxxx%2Findex.php%2Fxxxxxxx%2FMember%2Fregister%3Frecommend_id%3D11442%26id%3D87"; 
function replaceStr(str){ 
 str = str.replace(/%3A/g, ":"); 
 str = str.replace(/%2F/g, "/"); 
 str = str.replace(/%3F/g, "?"); 
 str = str.replace(/%3D/g, "="); 
 str = str.replace(/%26/g, "&"); 
 str = str.replace(/%2B/g, "+"); 
 str = str.replace(/%20/g, " "); 
 str = str.replace(/%23/g, "#"); 
 return str; 
} 
console.log(replaceStr(str));