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正文
在java开发中，几乎所有系统都有报表统计的功能，而报表统计的其中一个参数就是时间段，有环比同比时间段统计，有时间段统计，有周统计，有趋势图统计等，所以封装了该工具类，避免在每个统计方法中重复的计算这样那样的日期。
照旧先上工具类使用栗子：
System.out.println("201909环比日期="+ReportDateUtil.getHbMonth("201909"));
System.out.println("201909同比日期="+ReportDateUtil.getTbMonth("201909"));
System.out.println("201901-201909相隔月数="+ReportDateUtil.getPeriodAmount("20190101", "20190901", ReportDateUtil.MONTH));
// 用于趋势图中显示日期，当统计值为0时也是要显示的哦
System.out.println("201901-201909之间的日期列表="+ReportDateUtil.getPeriodDateList("20190101", "20190901", ReportDateUtil.MONTH));
ReportDateUtil.getMonthWeekGroupList("201909").forEach((k, v) -> {
// 计算9月份共有多少周，每周的日期
System.out.println("201909第"+k+"周:"+v.toString());
});
System.out.println("201909中的自然周为="+ReportDateUtil.getMonthWeekList("201909"));
上面使用例子打印如下
201909环比日期=201908
201909同比日期=201809
201901-201909相隔月数=8
201901-201909之间的日期列表=[201901, 201902, 201903, 201904, 201905, 201906, 201907, 201908, 201909]
201909第1周:[2019-09-01, 2019-09-02, 2019-09-03, 2019-09-04, 2019-09-05, 2019-09-06, 2019-09-07]
201909第2周:[2019-09-08, 2019-09-09, 2019-09-10, 2019-09-11, 2019-09-12, 2019-09-13, 2019-09-14]
201909第3周:[2019-09-15, 2019-09-16, 2019-09-17, 2019-09-18, 2019-09-19, 2019-09-20, 2019-09-21]
201909第4周:[2019-09-22, 2019-09-23, 2019-09-24, 2019-09-25, 2019-09-26, 2019-09-27, 2019-09-28]
201909第5周:[2019-09-29, 2019-09-30]
201909中的自然周为=[201939, 201936, 201938, 201937, 201940]下面给出完整的工具类，这是我项目中在报表统计时经常用到的，有需要的码友可以先收藏，说不定哪天就用到了。
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.Period;
import java.time.YearMonth;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAdjusters;
import java.time.temporal.WeekFields;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class ReportDateUtil {
private static final DateTimeFormatter DTF_YYYYMMDD = DateTimeFormatter.ofPattern("yyyyMMdd");
private static final DateTimeFormatter DTF_YYYYMM = DateTimeFormatter.ofPattern("yyyyMM");
private static final DateTimeFormatter DTF_YYYY = DateTimeFormatter.ofPattern("yyyy");
private static final String PATTERN_WEEK = "yyyyw";
public static final int YEAR = 1;
public static final int MONTH = 2;
public static final int DAY = 3;
public static void main(String[] args) {
System.out.println("201909环比日期="+ReportDateUtil.getHbMonth("201909"));
System.out.println("201909同比日期="+ReportDateUtil.getTbMonth("201909"));
System.out.println("201901-201909相隔月数="+ReportDateUtil.getPeriodAmount("20190101", "20190901", ReportDateUtil.MONTH));
System.out.println("201901-201909之间的日期列表="+ReportDateUtil.getPeriodDateList("20190101", "20190901", ReportDateUtil.MONTH));
ReportDateUtil.getMonthWeekGroupList("201909").forEach((k, v) -> {
System.out.println("201909第"+k+"周:"+v.toString());
});
System.out.println("201909中的自然周为="+ReportDateUtil.getMonthWeekList("201909"));
}
public static String getFirstOfMonth(String currMonth) {
currMonth = currMonth + "01";
LocalDate d = LocalDate.parse(currMonth, DTF_YYYYMMDD);
return DTF_YYYYMMDD.format(d.with(TemporalAdjusters.firstDayOfMonth()));
}
public static String getLastOfMonth(String currMonth) {
currMonth = currMonth + "01";
LocalDate d = LocalDate.parse(currMonth, DTF_YYYYMMDD);
return DTF_YYYYMMDD.format(d.with(TemporalAdjusters.lastDayOfMonth()));
}
public static String getFirstOfYear(String currYear) {
currYear = currYear + "0101";
LocalDate d = LocalDate.parse(currYear, DTF_YYYYMMDD);
return DTF_YYYYMMDD.format(d.with(TemporalAdjusters.firstDayOfYear()));
}
public static String getLastOfYear(String currYear) {
currYear = currYear + "0101";
LocalDate d = LocalDate.parse(currYear, DTF_YYYYMMDD);
return DTF_YYYYMMDD.format(d.with(TemporalAdjusters.lastDayOfYear()));
}
public static String getHbMonth(String currMonth) {
currMonth = currMonth + "01";
LocalDate d = LocalDate.parse(currMonth, DTF_YYYYMMDD);
return DTF_YYYYMM.format(d.minusMonths(1L));
}
public static String getTbMonth(String currMonth) {
currMonth = currMonth + "01";
LocalDate d = LocalDate.parse(currMonth, DTF_YYYYMMDD);
return DTF_YYYYMM.format(d.minusYears(1L));
}
public static List<String> getPeriodDateList(String startDate, String endDate, int unit) {
List<String> l = new ArrayList<>();
LocalDate start = LocalDate.parse(startDate, DTF_YYYYMMDD);
LocalDate end = LocalDate.parse(endDate, DTF_YYYYMMDD);
Period p = Period.between(start, end);
if (ReportDateUtil.YEAR == unit) {
for (int i = 0; i <= p.getYears(); i++) {
l.add(DTF_YYYY.format(start.plusYears(i)));
}
} else if (ReportDateUtil.MONTH == unit) {
for (int i = 0; i <= p.getMonths(); i++) {
l.add(DTF_YYYYMM.format(start.plusMonths(i)));
}
} else if (ReportDateUtil.DAY == unit) {
for (int i = 0; i <= p.getDays(); i++) {
l.add(DTF_YYYYMMDD.format(start.plusDays(i)));
}
}
return l;
}
public static List<String> getPeriodDateList(String startDate, String endDate, int unit, String pattern) {
DateTimeFormatter dtf = DateTimeFormatter.ofPattern(pattern);
List<String> l = new ArrayList<>();
LocalDate start = LocalDate.parse(startDate, DTF_YYYYMMDD);
LocalDate end = LocalDate.parse(endDate, DTF_YYYYMMDD);
Period p = Period.between(start, end);
if (ReportDateUtil.YEAR == unit) {
for (int i = 0; i <= p.getYears(); i++) {
l.add(dtf.format(start.plusYears(i)));
}
} else if (ReportDateUtil.MONTH == unit) {
for (int i = 0; i <= p.getMonths(); i++) {
l.add(dtf.format(start.plusMonths(i)));
}
} else if (ReportDateUtil.DAY == unit) {
for (int i = 0; i <= p.getDays(); i++) {
l.add(dtf.format(start.plusDays(i)));
}
}
return l;
}
public static List<String> getMonthWeekList(String currMonth) {
return getMonthWeekList(currMonth, PATTERN_WEEK);
}
public static List<String> getMonthWeekList(String currMonth, String pattern) {
final DateTimeFormatter DTF_WEEK = DateTimeFormatter.ofPattern(pattern);
YearMonth yearMonth = YearMonth.parse(currMonth, DTF_YYYYMM);
LocalDate start = LocalDate.now().with(yearMonth).with(TemporalAdjusters.firstDayOfMonth());
LocalDate end = LocalDate.now().with(yearMonth).with(TemporalAdjusters.lastDayOfMonth());
if(end.isAfter(LocalDate.now())){
end = LocalDate.now();
}
// 按周分组，设置一周的开始日期为 星期天
Map<String, List<LocalDate>> collect = Stream.iterate(start, localDate -> localDate.plusDays(1L))
.limit(ChronoUnit.DAYS.between(start, end) + 1)
.collect(Collectors.groupingBy(localDate -> DTF_WEEK.format(localDate)));
List<String> l = new ArrayList<>();
collect.forEach((k, v) -> l.add(k));
return l;
}
public static Map<Integer, List<LocalDate>> getMonthWeekGroupList(String currMonth) {
YearMonth yearMonth = YearMonth.parse(currMonth, DTF_YYYYMM);
LocalDate start = LocalDate.now().with(yearMonth).with(TemporalAdjusters.firstDayOfMonth());
LocalDate end = LocalDate.now().with(yearMonth).with(TemporalAdjusters.lastDayOfMonth());
// 按周分组，设置一周的开始日期为 星期天
return Stream.iterate(start, localDate -> localDate.plusDays(1L))
.limit(ChronoUnit.DAYS.between(start, end) + 1)
.collect(Collectors.groupingBy(localDate ->
localDate.get(WeekFields.of(DayOfWeek.SUNDAY, 1).weekOfMonth())));
}
public static int getPeriodAmount(String startDate, String endDate, int unit) {
LocalDate start = LocalDate.parse(startDate, DTF_YYYYMMDD);
LocalDate end = LocalDate.parse(endDate, DTF_YYYYMMDD);
Period p = Period.between(start, end);
if (ReportDateUtil.YEAR == unit) {
return p.getYears();
} else if (ReportDateUtil.MONTH == unit) {
return p.getMonths();
}
return p.getDays();
}
}
大部分系统都是有图表统计的，有图表统计的话基本都能使用到这个工具类。这也是我在多个项目中都用到，所以封装了这个工具类。