java 시스템 시간

long time = System.currentTimeMillis(); 

SimpleDateFormat dayTime = new SimpleDateFormat("yyyy-mm-dd hh:mm:ss");
//구분자 없이 사용할려면...
//SimpleDateFormat dayTime = new SimpleDateFormat("yyyyMMddHHmmss");

String str = dayTime.format(new Date(time));

System.out.println(str);

long start = System.currentTimeMillis() ; 

new trunc_tweet_tag("./message/");

long end = System.currentTimeMillis(); 

System.out.println((end-start)/1000 +" 초 걸림");