public static void main(String... aArgs) throws IOException{      
      String s = "\2.\1.domain.com";    
      System.out.println(filterCtrlChars(s));
      
  }

  public static String filterCtrlChars(String source){
      StringBuffer sf = new StringBuffer();
      for (char c : source.toCharArray()){
          if (Character.isISOControl(c)){
              sf.append("\\")
                    .append(Integer.toOctalString(c));       
          }else{
              sf.append(c);
          }
      }
      return sf.toString();
  }

------解决方案--------------------
探讨

能不能用replace？


------解决方案--------------------
一般都是用\\，更保险