Date常用方法

对比

//之后
a.after(b); //a在b之后则true 否则false
//之前
a.before(b); //a在b之前则true 否则false

获取时间信息

        Calendar startDate = Calendar.getInstance();
        startDate.setTime(new Date());
        System.out.println("年："+startDate.get(Calendar.YEAR));
        System.out.println("月："+startDate.get(Calendar.MONTH)+1);
        System.out.println("日："+startDate.get(Calendar.DATE));
        System.out.println("时："+startDate.get(Calendar.HOUR));
        System.out.println("分："+startDate.get(Calendar.MINUTE));
        System.out.println("秒："+startDate.get(Calendar.SECOND));
        System.out.println("一周的第几天："+startDate.get(Calendar.DAY_OF_WEEK));
        System.out.println("一月的第几天："+startDate.get(Calendar.DAY_OF_MONTH));
        System.out.println("一年的第几天："+startDate.get(Calendar.DAY_OF_YEAR));