Java编程,打印昨天的当前时刻

public class Demo {
 /*
  * Java编程,打印昨天的当前时刻
  */
 public static void main(String[] args){
  Calendar cal = Calendar.getInstance();
  cal.add(Calendar.DATE, -1);
  Date date = cal.getTime();
  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  String str = sdf.format(date);
  System.out.println(str);
 }

}