打印輸出昨天的當前時間

package ForeverLover;import java.text.SimpleDateFormat;import java.util.Calendar;public class DateSystem {/** * @author ForeverLover */public static void main(String[] args) {SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");Calendar cal = Calendar.getInstance();cal.add(Calendar.DATE, -1);System.out.PRintln(sdf.format(cal.getTime()));}}