Java获取系统时间的几种方法

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String ly_time = sdf.format(new java.util.Date());
System.out.println("现在时间是:"+ly_time);

String ly_time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(Calendar.getInstance().getTime());
System.out.println("现在时间是:"+ly_time);

public void time(){
int year=0;
int month=0;
int day=0;
Calendar c=Calendar.getInstance();//获得系统当前日期
year=c.get(Calendar.YEAR);
month=c.get(Calendar.MONTH)+1;//系统日期从0开始算起
day=c.get(Calendar.DAY_OF_MONTH);
System.out.println(year+""+month+" "+day);
}