1. Date类
1 Date day=new Date(); 2 SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 3 System.out.println(df.format(day)); 4 // 或者 5 Date date = new Date(); 6 String year = String.format("%tY", date); 7 String month = String.format("%tB", date); 8 String day = String.format("%te", date); 9 System.out.println(year+"-"+month+"-"+day);
2. System类
1 SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 2 System.out.println(df.format(System.currentTimeMillis()));
3. Calendar类
1 Calendar c = Calendar.getInstance();//可以对每个时间域单独修改 2 int year = c.get(Calendar.YEAR); 3 int month = c.get(Calendar.MONTH); 4 int date = c.get(Calendar.DATE); 5 int hour = c.get(Calendar.HOUR_OF_DAY); 6 int minute = c.get(Calendar.MINUTE); 7 int second = c.get(Calendar.SECOND); 8 System.out.println(year + "-" + month + "-" + date + " " +hour + ":" +minute + ":" + second);
总结：系统时间可通过Date类、Calendar类和System中的currentTimeMillis来获取，时间格式可通过调用SimpleDateFormat类和String中的format方法来设置。
