javaCalendar日期比较

public static void main(String[] args) throws Exception { 
   
String startTime = "2012-12-12 12:45:45"; 
String endTime = "2012-04-12 12:45:40"; 
String SYSendTime = "2012-11-12 12:45:40";
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
Date startDate = sdf.parse(startTime); 
Date endDate = sdf.parse(endTime); 
Calendar start = Calendar.getInstance(); 
Calendar end = Calendar.getInstance(); 
start.setTime(startDate); 
end.setTime(endDate); 
if(start.before(end)){ 
    
System.err.println("开始时间小于结束时间"); 
}else if(start.after(end)){ 
    
System.err.println("开始时间大于结束时间"); 
}else if(start.equals(end)){ 
    
System.err.println("开始时间等于结束时间"); 
}


}

 

//常用方法 
    public static void method(){ 
     
        Date date = new Date();  
        Calendar c = Calendar.getInstance();  
        //setTime():使用给定的Date设置此 Calendar 的时间 
        c.setTime(date);  
        //获取Calendar对象 
        Calendar cm = Calendar.getInstance();  
        //getTime():获取当前时间，类似于new Date(); 
        Date d = cm.getTime();  
        System.err.println("Calendar获得时间：" + d);  
        System.err.println("new Date创建的时间：" + date);  
        //getTimeInMillis():返回此 Calendar 的时间值，以毫秒为单位。 
        long dl = c.getTimeInMillis();  
        long ddate = cm.getTimeInMillis();  
        System.err.println("毫秒数：" + dl);  
        System.err.println("毫秒数：" + ddate);  
          
        //setTimeInMillis():用给定的 long 值设置此Calendar的当前时间值。 
        long sv = 123456;  
        Calendar sc = Calendar.getInstance();  
        sc.setTimeInMillis(sv);  
        SimpleDateFormat ss = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
        String st = ss.format(sc.getTime());  
        System.err.println(st);  
          
        //get():返回给定日历字段的值。 
        int year = c.get(Calendar.YEAR);  
        System.err.println(year);  
          
        //set():将给定的日历字段设置为给定值 
        c.set(Calendar.YEAR, 2);  
        int y = c.get(Calendar.YEAR);  
        System.err.println(y);//输出2 
          
        //Calendar比较：before(),after(),equals(),compareTo(). 
        try{ 
     
            String startTime = "2012-12-12 12:45:39";  
            String endTime = "2012-12-12 12:45:40";  
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
            Date startDate = sdf.parse(startTime);  
            Date endDate = sdf.parse(endTime);  
            Calendar start = Calendar.getInstance();  
            Calendar end = Calendar.getInstance();  
            start.setTime(startDate);  
            end.setTime(endDate);  
            if(start.before(end)){ 
     
                System.err.println("开始时间小于结束时间");  
            }else if(start.after(end)){ 
     
                System.err.println("开始时间大于结束时间");  
            }else if(start.equals(end)){ 
     
                System.err.println("开始时间等于结束时间");  
            }  
            /* * start < end 返回-1 * start = end 返回0 * start > end 返回1 */  
            int count = start.compareTo(end);  
            System.err.println(count);  
              
            //add():为给定的日历字段添加或减去指定的时间量 
            start.add(Calendar.YEAR, -3);  
            System.err.println("原来的时间：" + startTime);  
            System.err.println("add后的时间：" + sdf.format(start.getTime()));  
              
            //toString():转换为字符串 
            System.err.println(start.toString());  
        }catch(Exception e){ 
   }  
    }  
    //常用属性 
    public static void param(){ 
     
        Date date = new Date();  
        Calendar c = Calendar.getInstance();  
        c.setTime(date);  
        //Calendar.YEAR:日期中的年 
        int year = c.get(Calendar.YEAR);  
        //Calendar.MONTH:日期中的月，需要加1 
        int mounth = c.get(Calendar.MONTH) + 1;  
        //Calendar.DATE:日期中的日 
        int day = c.get(Calendar.DATE);  
        //Calendar.HOUR:日期中的小时(12小时制) 
        int hour = c.get(Calendar.HOUR);  
        //Calendar.HOUR_OF_DAY：24小时制 
        int HOUR_OF_DAY = c.get(Calendar.HOUR_OF_DAY);  
        //Calendar.MINUTE:日期中的分钟 
        int minute = c.get(Calendar.MINUTE);  
        //Calendar.SECOND:日期中的秒 
        int second = c.get(Calendar.SECOND);  
        System.err.println(year + "-" + mounth + "-" + day + " " + hour + ":" + minute + ":" + second);  
          
        //Calendar.WEEK_OF_YEAR:当前年中星期数 
        int WEEK_OF_YEAR = c.get(Calendar.WEEK_OF_YEAR);  
        //Calendar.WEEK_OF_MONTH:当前月中星期数 
        int WEEK_OF_MONTH = c.get(Calendar.WEEK_OF_MONTH);  
        //Calendar.DAY_OF_YEAR:当前年中的第几天 
        int DAY_OF_YEAR = c.get(Calendar.DAY_OF_YEAR);  
        //Calendar.DAY_OF_MONTH:当前月中的第几天 
        int DAY_OF_MONTH = c.get(Calendar.DAY_OF_MONTH);  
        //Calendar.DAY_OF_WEEK:当前星期的第几天(星期天表示第一天，星期六表示第七天) 
        int  DAY_OF_WEEK = c.get(Calendar.DAY_OF_WEEK);  
        //Calendar.DAY_OF_WEEK_IN_MONTH:当前月中的第几个星期 
        int DAY_OF_WEEK_IN_MONTH = c.get(Calendar.DAY_OF_WEEK_IN_MONTH);  
          
        try{ 
     
            SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
            Date ampm = format.parse("2012-12-15 21:59:59");  
            Calendar cc = Calendar.getInstance();  
            cc.setTime(ampm);  
            //AM_PM:HOUR 是在中午之前还是在中午之后,在中午12点之前返回0，在中午12点(包括12点)之后返回1 
            int AM_PM = cc.get(Calendar.AM_PM);  
        }catch(Exception e){ 
   }  
          
    }  
}