时间，日期，日历

 1     //获取当天0点时间
 2     public static String getDate1(){
 3         
 4         Calendar cal = Calendar.getInstance();
 5         cal.set(Calendar.HOUR_OF_DAY, 0);//控制时
 6         cal.set(Calendar.MINUTE, 0);//控制分
 7         cal.set(Calendar.SECOND, 0);//控制秒
 8         
 9         Date time = cal.getTime();
10 
11         SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
12         String format = sdf.format(time);
13         
14         return null;
15     }