88
99
1010public class HLLUtils {
11- public static String TIME_FORMAT = "yyyyMMddHHmm" ;
1211 private static String TIME_FORMAT_MONTH_DAY = "MMdd" ;
1312 private static String TIME_FORMAT_DAY_MINUTES = "MMddHHmm" ;
1413 private static String TIME_FORMAT_DAY_HOURS = "MMddHH" ;
15- static SimpleDateFormat FORMAT_MONTH_DAY = new SimpleDateFormat (TIME_FORMAT_MONTH_DAY );
16- static SimpleDateFormat FORMAT_DAY_HOURS = new SimpleDateFormat (TIME_FORMAT_DAY_HOURS );
17- static SimpleDateFormat FORMAT_DAY_MINUTES = new SimpleDateFormat (TIME_FORMAT_DAY_MINUTES );
14+ private static SimpleDateFormat FORMAT_MONTH_DAY = new SimpleDateFormat (TIME_FORMAT_MONTH_DAY );
15+ private static SimpleDateFormat FORMAT_DAY_HOURS = new SimpleDateFormat (TIME_FORMAT_DAY_HOURS );
16+ private static SimpleDateFormat FORMAT_DAY_MINUTES = new SimpleDateFormat (TIME_FORMAT_DAY_MINUTES );
1817
18+ /**
19+ * 获取两个日期之间的键
20+ *
21+ * @param d1 日期1
22+ * @param d2 日期2
23+ * @return 键列表
24+ */
1925 public static List <String > parse (Date d1 , Date d2 ) {
20- ArrayList list ;
26+ List < String > list = new ArrayList <>() ;
2127 if (d1 .compareTo (d2 ) == 0 ) {
22- return Collections . emptyList () ;
28+ return list ;
2329 }
2430
25- // if less than an hour, sum all minutes
31+ // 若时间差小于 1 小时
2632 long delta = d2 .getTime () - d1 .getTime ();
2733 if (delta == 0 ) {
28- return Collections . emptyList () ;
34+ return list ;
2935 }
3036 if (delta < DateUtils .MILLIS_PER_HOUR ) {
3137 int minutesDiff = (int ) (delta / DateUtils .MILLIS_PER_MINUTE );
32- list = new ArrayList <String >();
3338 Date date1Increment = d1 ;
3439 while (d2 .compareTo (date1Increment ) > 0 && minutesDiff > 0 ) {
3540 list .add (FORMAT_DAY_MINUTES .format (date1Increment ));
3641 date1Increment = DateUtils .addMinutes (date1Increment , 1 );
3742 }
38- // if less than an day, trim hours sum all, pass minutes part
43+ // 若时间差小于 1 天
3944 } else if (delta < DateUtils .MILLIS_PER_DAY ) {
40- list = new ArrayList <String >();
4145 Date dateLastPortionHour = DateUtils .truncate (d2 , Calendar .HOUR_OF_DAY );
4246 list .addAll (parse (dateLastPortionHour , d2 ));
4347 long delta2 = dateLastPortionHour .getTime () - d1 .getTime ();
@@ -49,13 +53,11 @@ public static List<String> parse(Date d1, Date d2) {
4953 }
5054 list .addAll (parse (d1 , DateUtils .addHours (dateLastPortionHour , -1 * hoursDiff )));
5155 } else {
52- list = new ArrayList <String >();
5356 Date dateLastPortionDay = DateUtils .truncate (d2 , Calendar .DAY_OF_MONTH );
5457 list .addAll (parse (dateLastPortionDay , d2 ));
5558 long delta2 = dateLastPortionDay .getTime () - d1 .getTime ();
56- // if less than an month, trim days sum all, pass hours part
59+ // 若时间差小于 1 个月
5760 int daysDiff = (int ) (delta2 / DateUtils .MILLIS_PER_DAY );
58- // Date date1Increment = d1;
5961 Date date1Increment = DateUtils .addDays (dateLastPortionDay , -1 * daysDiff );
6062 while (dateLastPortionDay .compareTo (date1Increment ) > 0 && daysDiff > 0 ) {
6163 list .add (FORMAT_MONTH_DAY .format (date1Increment ));
@@ -66,19 +68,70 @@ public static List<String> parse(Date d1, Date d2) {
6668 return list ;
6769 }
6870
71+ /**
72+ * 获取从 date 往前推 minutes 分钟的键列表
73+ *
74+ * @param date 特定日期
75+ * @param minutes 分钟数
76+ * @return 键列表
77+ */
6978 public static List <String > getLastMinutes (Date date , int minutes ) {
7079 return parse (DateUtils .addMinutes (date , -1 * minutes ), date );
7180 }
7281
82+ /**
83+ * 获取从 date 往前推 hours 个小时的键列表
84+ *
85+ * @param date 特定日期
86+ * @param hours 小时数
87+ * @return 键列表
88+ */
7389 public static List <String > getLastHours (Date date , int hours ) {
7490 return parse (DateUtils .addHours (date , -1 * hours ), date );
7591 }
7692
93+ /**
94+ * 获取从 date 开始往前推 days 天的键列表
95+ *
96+ * @param date 特定日期
97+ * @param days 天数
98+ * @return 键列表
99+ */
77100 public static List <String > getLastDays (Date date , int days ) {
78101 return parse (DateUtils .addDays (date , -1 * days ), date );
79102 }
80103
104+ /**
105+ * 为keys列表添加前缀
106+ *
107+ * @param keys 键列表
108+ * @param prefix 前缀符号
109+ * @return 添加了前缀的键列表
110+ */
81111 public static List <String > addPrefix (List <String > keys , String prefix ) {
82112 return keys .stream ().map (key -> prefix + key ).collect (Collectors .toList ());
83113 }
114+ 115+ public static void main (String [] args ) {
116+ Date d1 = new Date ();
117+ d1 .setTime ((long ) (System .currentTimeMillis () - 3600 * 1000 * 24 * 1.2 ));
118+ Date d2 = new Date ();
119+ List <String > res = parse (d1 , d2 );
120+ res .forEach (System .out ::println );
121+ List <String > newRes = addPrefix (res , "USER:LOGIN:" );
122+ System .out .println ("-------" );
123+ newRes .forEach (System .out ::println );
124+ 125+ List <String > lastThreeDays = getLastDays (new Date (), 3 );
126+ System .out .println ("-------" );
127+ lastThreeDays .forEach (System .out ::println );
128+ 129+ List <String > lastTwoHours = getLastHours (new Date (), 2 );
130+ System .out .println ("-------" );
131+ lastTwoHours .forEach (System .out ::println );
132+ 133+ List <String > lastFourMinutes = getLastMinutes (new Date (), 4 );
134+ System .out .println ("-------" );
135+ lastFourMinutes .forEach (System .out ::println );
136+ }
84137}
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