https://blog.csdn.net/itmyhome1990/article/details/85619804
Java获取指定月份的最后一天
麦田 2019-01-02 17:43:38  8036  收藏 1
 展开
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
public class DUtil {
     public static String getLastDayOfMonth(String yearMonth) {
         int year = Integer.parseInt(yearMonth.split("-")[0]);  //年
         int month = Integer.parseInt(yearMonth.split("-")[1]); //月
         Calendar cal = Calendar.getInstance();
         // 设置年份
         cal.set(Calendar.YEAR, year);
         // 设置月份
         // cal.set(Calendar.MONTH, month - 1);
         cal.set(Calendar.MONTH, month); //设置当前月的上一个月
         // 获取某月最大天数
         //int lastDay = cal.getActualMaximum(Calendar.DATE);
         int lastDay = cal.getMinimum(Calendar.DATE); //获取月份中的最小值,即第一天
         // 设置日历中月份的最大天数
         //cal.set(Calendar.DAY_OF_MONTH, lastDay);
         cal.set(Calendar.DAY_OF_MONTH, lastDay - 1); //上月的第一天减去1就是当月的最后一天
         // 格式化日期
         SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
         return sdf.format(cal.getTime());
     }
     
     public static void main(String[] args) {
         System.out.println(getLastDayOfMonth("2019-02"));
     }
 }
 1
  
 输出:
package com.unicom.property.core.util;import com.unicom.property.common.query.DateQuery;
import com.unicom.property.common.enums.StatisticsPeriodEnum;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;/*** @Copyright: Unicom (Zhejiang) Industrial Internet Co., Ltd.    2020 <br/>* @Desc:      <br/>* @ProjectName: property-charge <br/>* @Date: 2020/4/30 18:53 <br/>* @Author: yangjiabin*/
public class DateSelectBoxUtil {/*** 获取指定年月的最后一天* @param year* @param month* @return*/public static String getLastDayOfMonth1(int year, int month) {
//    Calendar cal = Calendar.getInstance();
//    //设置年份
//    cal.set(Calendar.YEAR, year);
//    //设置月份
//    cal.set(Calendar.MONTH, month-1);
//    //获取某月最大天数
//    int lastDay = cal.getActualMaximum(Calendar.DATE);
//    //设置日历中月份的最大天数
//    cal.set(Calendar.DAY_OF_MONTH, lastDay);
//    //格式化日期
//    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
//    return sdf.format(cal.getTime());  有问题//    int year = Integer.parseInt(yearMonth.split("-")[0]);  //年
//    int month = Integer.parseInt(yearMonth.split("-")[1]); //月Calendar cal = Calendar.getInstance();// 设置年份cal.set(Calendar.YEAR, year);// 设置月份// cal.set(Calendar.MONTH, month - 1);cal.set(Calendar.MONTH, month); //设置当前月的上一个月// 获取某月最大天数//int lastDay = cal.getActualMaximum(Calendar.DATE);int lastDay = cal.getMinimum(Calendar.DATE); //获取月份中的最小值,即第一天// 设置日历中月份的最大天数//cal.set(Calendar.DAY_OF_MONTH, lastDay);cal.set(Calendar.DAY_OF_MONTH, lastDay - 1); //上月的第一天减去1就是当月的最后一天// 格式化日期SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");return sdf.format(cal.getTime());}/*** 获取指定年月的第一天* @param year* @param month* @return*/public static String getFirstDayOfMonth1(int year, int month) {Calendar cal = Calendar.getInstance();//设置年份cal.set(Calendar.YEAR, year);//设置月份cal.set(Calendar.MONTH, month-1);//获取某月最小天数int firstDay = cal.getMinimum(Calendar.DATE);//设置日历中月份的最小天数cal.set(Calendar.DAY_OF_MONTH,firstDay);//格式化日期SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");return sdf.format(cal.getTime());}/***  获取指定月第一天** @param day  传入2019-02* @return*/public static String getFirstDayOfMonth2(String day) {String[] split = day.split("-");int year = Integer.parseInt(split[0]);int month= Integer.parseInt(split[1]);String firstDayOfMonth1 = getFirstDayOfMonth1(year, month);return firstDayOfMonth1;}/***  获取指定月份最后一天* @param day  传入2019-02* @return*/public static String getLastDayOfMonth2(String day) {String[] split = day.split("-");int year = Integer.parseInt(split[0]);int month= Integer.parseInt(split[1]);String lastDayOfMonth1 = getLastDayOfMonth1(year, month);return lastDayOfMonth1;}public static Map<String, Date> getBillFinaldate(DateQuery dateQuery) {//按月String byMonthValue = String.valueOf(StatisticsPeriodEnum.MONTH.getCode()) ;//按季度String byQuarterlyValue = String.valueOf(StatisticsPeriodEnum.QUARTER.getCode()) ;//按半年String byHalfYearValue = String.valueOf(StatisticsPeriodEnum.HALF_YEAR.getCode()) ;//按年String byYearValue = String.valueOf(StatisticsPeriodEnum.YEAR.getCode()) ;Date dateStart = new Date();Date dateEnd = new Date();//按月if(byMonthValue.equals(dateQuery.getSettleCycle())){String year = dateQuery.getYear();String month = dateQuery.getTime();//2020-5String yearMonth = year + "-" + month;String startime = DateSelectBoxUtil.getFirstDayOfMonth2(yearMonth) + " 00:00:00";String endtime = DateSelectBoxUtil.getLastDayOfMonth2(yearMonth) + " 23:59:59";//2020-5-1 00:00:00  至  2020-5-31 23:59:59   指定月份dateStart = DateUtil.parseYyyyMMddHHmmss(startime);dateEnd= DateUtil.parseYyyyMMddHHmmss(endtime);}//按季度if(byQuarterlyValue.equals(dateQuery.getSettleCycle())){String year = dateQuery.getYear();Integer time = Integer.parseInt(dateQuery.getTime());//假设为第一季度String startMonth = String.valueOf(3*time-2);String endMonth = String.valueOf(3*time);//2020-7String startYearMonth = year + "-" + startMonth;//2020-9String endYearMonth = year + "-" + endMonth;String startime = DateUtil.getFirstDayOfMonth2(startYearMonth) + " 00:00:00";String endtime = DateUtil.getLastDayOfMonth2(endYearMonth) + " 23:59:59";//2020-7-1 00:00:00  至  2020-9-30 23:59:59   指定月份dateStart = DateUtil.parseYyyyMMddHHmmss(startime);dateEnd= DateUtil.parseYyyyMMddHHmmss(endtime);}//按半年if(byHalfYearValue.equals(dateQuery.getSettleCycle())){String year = dateQuery.getYear();Integer time = Integer.parseInt(dateQuery.getTime());//假设为上半年String startMonth = String.valueOf(6*time-5);String endMonth = String.valueOf(6*time);//2020-7String startYearMonth = year + "-" + startMonth;//2020-12String endYearMonth = year + "-" + endMonth;String startime = DateUtil.getFirstDayOfMonth2(startYearMonth) + " 00:00:00";String endtime = DateUtil.getLastDayOfMonth2(endYearMonth) + " 23:59:59";//2020-7-1 00:00:00  至  2020-12-31 23:59:59   指定月份dateStart = DateUtil.parseYyyyMMddHHmmss(startime);dateEnd= DateUtil.parseYyyyMMddHHmmss(endtime);}//按年if(byYearValue.equals(dateQuery.getSettleCycle())){String year = dateQuery.getYear();//2020-5String startime = year + "-1-1 00:00:00";String endtime = year + "-12-31 23:59:59";//2020-1-1 00:00:00  至  2020-12-31 23:59:59   指定月份dateStart = DateUtil.parseYyyyMMddHHmmss(startime);dateEnd= DateUtil.parseYyyyMMddHHmmss(endtime);}Map<String,Date> map = new HashMap();map.put("dateStart",dateStart);map.put("dateEnd",dateEnd);return map;}public static void main(String[] args) {
//    System.out.println("按月");
//    for(int i = 1 ;i<=12;i++){
//      byMounth(String.valueOf(i));
//    }
//    System.out.println("按季度");
//    for(int i = 1 ;i<=4;i++) {
//      byQuarter(String.valueOf(i));
//    }
//    System.out.println("按半年");
//    for(int i = 1 ;i<=2;i++) {
//      byHelfYear(String.valueOf(i));
//    }
//    System.out.println("按年");
//    for(int i = 1 ;i<=2;i++) {
//      byYear(String.valueOf(i));
//    }//0-按月 1-按季度 2-按半年  3-年DateQuery dateQuery = new DateQuery();dateQuery.setYear("2020");dateQuery.setSettleCycle("0");List<Map<String, Date>> mounthList = getMounthList(dateQuery);printList(mounthList);System.out.println();//0-按月 1-按季度 2-按半年  3-年DateQuery dateQuery2 = new DateQuery();dateQuery2.setYear("2020");dateQuery2.setSettleCycle("1");List<Map<String, Date>> mounthList2 = getQuarterList(dateQuery2);printList(mounthList2);System.out.println();//0-按月 1-按季度 2-按半年  3-年DateQuery dateQuery3 = new DateQuery();dateQuery3.setYear("2020");dateQuery3.setSettleCycle("2");List<Map<String, Date>> mounthList3 = getHelfYearList(dateQuery3);printList(mounthList3);System.out.println();//0-按月 1-按季度 2-按半年  3-年DateQuery dateQuery4 = new DateQuery();dateQuery4.setYear("2020");dateQuery4.setSettleCycle("3");List<Map<String, Date>> mounthList4 = getYearList(dateQuery4);printList(mounthList4);System.out.println();}public static void printList(List<Map<String, Date>> mounthList) {System.out.println("---------------------------------------");for(Map<String, Date> temp: mounthList){Date dateStart = temp.get("dateStart");Date dateEnd = temp.get("dateEnd");System.out.println(DateUtil.formatYyyyMMddHHmmss(dateStart)+" --> "+DateUtil.formatYyyyMMddHHmmss(dateEnd));System.out.println();}}public static List<Map<String, Date>> getMounthList(DateQuery dateQuery) {//0-按月 1-按季度 2-按半年  3-年System.out.println("按月");List<Map<String, Date>> timeList= new ArrayList<>();for(int i = 1 ;i<=12;i++){dateQuery.setTime(String.valueOf(i));Map<String, Date> billFinaldate = DateSelectBoxUtil.getBillFinaldate(dateQuery);timeList.add(billFinaldate);}return timeList;}public static void byMounth(String mounth) {//0-按月 1-按季度 2-按半年  3-年DateQuery dateQuery = new DateQuery();dateQuery.setYear("2020");dateQuery.setSettleCycle("0");dateQuery.setTime(mounth);Map<String, Date> billFinaldate = DateSelectBoxUtil.getBillFinaldate(dateQuery);Date dateStart = billFinaldate.get("dateStart");Date dateEnd = billFinaldate.get("dateEnd");System.out.println(DateUtil.formatYyyyMMddHHmmss(dateStart)+" --> "+DateUtil.formatYyyyMMddHHmmss(dateEnd));System.out.println();}public static List<Map<String, Date>> getQuarterList(DateQuery dateQuery) {//0-按月 1-按季度 2-按半年  3-年System.out.println("按季度");List<Map<String, Date>> timeList= new ArrayList<>();for(int i = 1 ;i<=4;i++){dateQuery.setTime(String.valueOf(i));Map<String, Date> billFinaldate = DateSelectBoxUtil.getBillFinaldate(dateQuery);timeList.add(billFinaldate);}return timeList;}public static void byQuarter(String time) {//0-按月 1-按季度 2-按半年  3-年DateQuery dateQuery = new DateQuery();dateQuery.setYear("2020");dateQuery.setSettleCycle("1");dateQuery.setTime(time);Map<String, Date> billFinaldate = DateSelectBoxUtil.getBillFinaldate(dateQuery);Date dateStart = billFinaldate.get("dateStart");Date dateEnd = billFinaldate.get("dateEnd");System.out.println(DateUtil.formatYyyyMMddHHmmss(dateStart)+" --> "+DateUtil.formatYyyyMMddHHmmss(dateEnd));System.out.println();}public static List<Map<String, Date>> getHelfYearList(DateQuery dateQuery) {//0-按月 1-按季度 2-按半年  3-年System.out.println("按半年");List<Map<String, Date>> timeList= new ArrayList<>();for(int i = 1 ;i<=2;i++){dateQuery.setTime(String.valueOf(i));Map<String, Date> billFinaldate = DateSelectBoxUtil.getBillFinaldate(dateQuery);timeList.add(billFinaldate);}return timeList;}public static void byHelfYear(String time) {//0-按月 1-按季度 2-按半年  3-年DateQuery dateQuery = new DateQuery();dateQuery.setYear("2020");dateQuery.setSettleCycle("2");dateQuery.setTime(time);Map<String, Date> billFinaldate = DateSelectBoxUtil.getBillFinaldate(dateQuery);Date dateStart = billFinaldate.get("dateStart");Date dateEnd = billFinaldate.get("dateEnd");System.out.println(DateUtil.formatYyyyMMddHHmmss(dateStart)+" --> "+DateUtil.formatYyyyMMddHHmmss(dateEnd));System.out.println();}public static List<Map<String, Date>> getYearList(DateQuery dateQuery) {//0-按月 1-按季度 2-按半年  3-年System.out.println("按年");List<Map<String, Date>> timeList= new ArrayList<>();for(int i = 1 ;i<=1;i++){dateQuery.setTime(String.valueOf(i));Map<String, Date> billFinaldate = DateSelectBoxUtil.getBillFinaldate(dateQuery);timeList.add(billFinaldate);}return timeList;}public static void byYear(String time) {//0-按月 1-按季度 2-按半年  3-年DateQuery dateQuery = new DateQuery();dateQuery.setYear("2020");dateQuery.setSettleCycle("3");dateQuery.setTime(time);Map<String, Date> billFinaldate = DateSelectBoxUtil.getBillFinaldate(dateQuery);Date dateStart = billFinaldate.get("dateStart");Date dateEnd = billFinaldate.get("dateEnd");System.out.println(DateUtil.formatYyyyMMddHHmmss(dateStart)+" --> "+DateUtil.formatYyyyMMddHHmmss(dateEnd));System.out.println();}}
 
2019-02-28
 1
 PS:2月份获取的最后一天日期不对,抱歉,已改正。
 修改为:用当前月的上个月的第一天减去1就是当月的最后一天。
 更正:2019-11-29
作者:itmyhome
 麦田   博客专家
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佬油条:2月不对5个月前收起评论
 码哥麦田回复佬油条:已修改,多谢指正5个月前
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eternalsing:很强 棒棒哒6个月前
 码哥神界码农-D-艾斯:用2月试了吗?9个月前收起评论
 nameFnameHnameW回复神界码农-D-艾斯:
 没事了,看错了,之前别人写错了,谢谢。6个月前
 码哥神界码农-D-艾斯回复nameFnameHnameW:
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             cal.clear();
            //code....
 先clear,再做其他业务。6个月前
 nameFnameHnameW回复神界码农-D-艾斯:
 clear了,2月和9月也是不对啊6个月前
 XV_DD回复神界码农-D-艾斯:感谢8个月前
 码哥神界码农-D-艾斯回复码哥神界码农-D-艾斯:
 你少写一句代码,在Calendar cal = Calendar.getInstance(); 之后,必须clear一次,否则取出的值是上一次的。9个月前
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武中奇:超级爱你,比心10个月前
 ————————————————
 版权声明:本文为CSDN博主「麦田」的原创文章,遵循CC 4.0 BY-SA版权协议,转载请附上原文出处链接及本声明。
 原文链接:https://blog.csdn.net/itmyhome1990/article/details/85619804