Java调用cmd命令返回结果正则匹配

try {
			String str="";
			Runtime runtime=Runtime.getRuntime();
			Process process=runtime.exec("ping 127.0.0.1");
			BufferedReader input=new BufferedReader(new InputStreamReader(process.getInputStream(),"gbk"));
			String line=null;
			while((line=input.readLine())!=null){
				str+=line+"\n";	
			}
			System.out.println(str);
		      String pattern = "TTL(.*?)\n";
		      Pattern r = Pattern.compile(pattern);
		      Matcher m = r.matcher(str);
		      if (m.find( )){
		         System.out.println(m.group(0) );
		      }

		} catch (Exception e) {
			e.printStackTrace();
		}
	}