临时存放 简单 时间

public static void test(){
Calendar now = Calendar.getInstance();
int year = now.get(Calendar.YEAR);   
int date = now.get(Calendar.DAY_OF_MONTH);   
int month = now.get(Calendar.MONTH) + 1;   
int hour = now.get(Calendar.HOUR);   
int min = now.get(Calendar.MINUTE);   
int sec = now.get(Calendar.SECOND); 

SimpleDateFormat df = new  SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

Calendar calendar = Calendar.getInstance();  
calendar.roll(Calendar.DAY_OF_YEAR,-1);
System.out.println("昨天："+df.format(calendar.getTime()));

calendar= Calendar.getInstance();
calendar.set(Calendar.HOUR, 6);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
System.out.println("今天："+df.format(calendar.getTime()));

calendar= Calendar.getInstance();
calendar.roll(Calendar.DAY_OF_YEAR,1);  
System.out.println("明天："+df.format(calendar.getTime()));
}


select to_date('2005-01-01 13:14:20','yyyy-MM-dd HH24:mm:ss') from dual;
select to_char(sysdate,'yyyy-MM-dd HH24:mi:ss') from dual;