Calendar代替Date常用方法小记

　　　　 // 获取当前各自日期实例
        Calendar calendar = Calendar.getInstance();
        Date date = new Date();

        // 相互转换
        Date temp = calendar.getTime();
        calendar.setTime(date);

        // 设置时分秒，Calendar完全替换Date
        calendar.set(Calendar.HOUR_OF_DAY,9);
        calendar.set(Calendar.MINUTE,30);
        calendar.set(Calendar.SECOND,0);
        
        // 时间比较，Calendar完全替换Date+1
        Calendar calendar1 = Calendar.getInstance();
        // before/after参数可为Calendar或Date
        Boolean tem = calendar.before(calendar);
        Boolean tem1 = calendar.after(calendar);
        Boolean tem2 = calendar.after(date);
        
        // 日期格式转换，commons-lang 
        // 日期转字符串 Date--String
        String dateStr = DateFormatUtils.format(date,"yyyy-MM-dd HH:MM:SS");
        // 字符串转日期 String--Date
        String[] pattern = new String[]{"yyyy-MM","yyyyMM","yyyy/MM",
                "yyyyMMdd","yyyy-MM-dd","yyyy/MM/dd",
                "yyyyMMddHHmmss",
                "yyyy-MM-dd HH:mm:ss",
                "yyyy/MM/dd HH:mm:ss"};
        String test = "2018-5-22";
        Date date1 = DateUtils.parseDate(test, pattern);