Java开发基础日期类代码详解

时间:2022-09-23 16:30:05

由于工作关系,很久没更新博客了,今天就给大家带来一篇Java实现获取指定月份的星期与日期对应关系的文章,好了,不多说,我们直接上代码:

一、日期工具类

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package com.lyz.date;
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;
import com.chwl.medical.utils.common.CollectionUtils;
import com.chwl.medical.utils.common.ObjectUtils;
/**
 * 日期工具类,获取指定月份的星期与日期的对应关系
 * @author liuyazhuang
 *
 */
public class DateUtils {
    public static final String DATE_FORMAT = "yyyy-MM-dd";
    public enum Type{
        Year, Month, Date
    }
    /**
     * 获取两个时间之间的年份
     * @param startDate
     * @param endDate
     * @return
     */
    public static int getYears(Date startDate, Date endDate, Type type){
        int count = 0;
         Calendar calBegin = Calendar.getInstance(); //获取日历实例
         Calendar calEnd = Calendar.getInstance();
         calBegin.setTime(startDate);
         calEnd.setTime(endDate);
         if(Type.Year == type){
             count = calEnd.get(Calendar.YEAR) - calBegin.get(Calendar.YEAR);
         }else if(Type.Month == type){
             count = calEnd.get(Calendar.MONTH) - calBegin.get(Calendar.MONTH);
         }else{
             count = calEnd.get(Calendar.DATE) - calBegin.get(Calendar.DATE);
         }
         return count;
    }
    /**
     * 获取指定月份的所有日期和星期集合
     * @param offset:起止月份, 0:当前月, 1:下一个月; 2下下月; 以此类推... -1:上一个月; -2:上上一个月 ; 以此类推....
     * @param length:终止月份, 0:当前月, 1:下一个月; 2下下月; 以此类推... -1:上一个月; -2:上上一个月 ; 以此类推....
     * @return:日期和星期集合:星期为key 日期为value
     */
    public static Map<String, List<String>> getKeyFromMapByValue(int offset, int length){
        return getKeyFromMapByValue(getDateKeyWeekValue(offset, length));
    }
    /**
     * 将以date为key, week为value的map转化为以week为key, date为value的map
     * @param dateWeek
     * @return
     */
    public static Map<String, List<String>> getKeyFromMapByValue(Map<String, String> dateWeek){
        Map<String, List<String>> weekDate = new HashMap<String, List<String>>();
        if(!CollectionUtils.isEmpty(dateWeek)){
            for(Map.Entry<String, String> entry : dateWeek.entrySet()){
                //获取日期集合
                List<String> list = weekDate.get(entry.getValue());
                if(ObjectUtils.isEmpty(list)){
                    list = new ArrayList<String>();
                }
                list.add(entry.getKey());
                weekDate.put(entry.getValue(), list);
            }
        }
        return weekDate;
    }
    /**
     * 获取指定月份的所有日期和星期集合
     * @param offset:起止月份, 0:当前月, 1:下一个月; 2下下月; 以此类推... -1:上一个月; -2:上上一个月 ; 以此类推....
     * @param length:终止月份, 0:当前月, 1:下一个月; 2下下月; 以此类推... -1:上一个月; -2:上上一个月 ; 以此类推....
     * @return:日期和星期集合:日期为key 星期为value
     */
    public static Map<String, String> getDateKeyWeekValue(int offset, int length){
        Map<String, String> map = new HashMap<String, String>();
        for(int i = offset; i <= length; i++){
            List<Date> list = getAllTheDateOftheMonth(new Date(),i);
            for(Date date: list){
                String weekDay = getDateOfWeek(date);
                map.put(parseDateToString(date, DATE_FORMAT), weekDay);
            }
        }
        return map;
    }
    /**
     * 获取当前日期所在月份的所有日期,指定月份的所有日期
     * @param date:当前日期
     * @param n:1下一月;2:下下月..以此类推; -1:上月,-2:上上月...以此类推
     * @return:返回指定月份的所有日期
     */
    public static List<Date> getAllTheDateOftheMonth(Date date, int n) {
        List<Date> list = new ArrayList<Date>();
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        cal.set(Calendar.DATE, 1);
        cal.add(Calendar.MONTH, n);
        int month = cal.get(Calendar.MONTH);
        while(cal.get(Calendar.MONTH) == month){
            list.add(cal.getTime());
            cal.add(Calendar.DATE, 1);
        }
        return list;
    }
    /**
     * 根据日期获得星期
     * @param date
     * @return
     */
    public static String getDateOfWeek(Date date) {
        //String[] weekDaysName = { "星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六" };
        String[] weekDaysCode = { "0", "1", "2", "3", "4", "5", "6" };
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        int intWeek = calendar.get(Calendar.DAY_OF_WEEK) - 1;
        if(intWeek < 0) intWeek = 0;
        return weekDaysCode[intWeek];
    }
    public static String parseDateToString(Date date, String formatString) {
        return getSimpleDateFormat(formatString).format(date);
    }
    public static SimpleDateFormat getSimpleDateFormat(String formatString) {
        return new SimpleDateFormat(formatString);
    }
}

二、测试类

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package com.lyz.date;
import net.sf.json.JSONObject;
/**
 * 测试工具类
 * @author liuyazhuang
 *
 */
public class TestDate {
  public static void main(String[] args) {
    System.out.println(JSONObject.fromObject(DateUtils.getDateKeyWeekValue(-1, 1)));
    System.out.println(JSONObject.fromObject(DateUtils.getKeyFromMapByValue(-1,1)));
  }
}

三、测试结果

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{
  "2017-02-28": "2",
  "2017-04-19": "3",
  "2017-04-17": "1",
  "2017-02-25": "6",
  "2017-04-18": "2",
  "2017-02-24": "5",
  "2017-04-15": "6",
  "2017-02-27": "1",
  "2017-04-16": "0",
  "2017-02-26": "0",
  "2017-04-13": "4",
  "2017-02-21": "2",
  "2017-04-14": "5",
  "2017-02-20": "1",
  "2017-04-11": "2",
  "2017-02-23": "4",
  "2017-04-12": "3",
  "2017-02-22": "3",
  "2017-04-21": "5",
  "2017-04-20": "4",
  "2017-04-08": "6",
  "2017-04-09": "0",
  "2017-04-04": "2",
  "2017-04-05": "3",
  "2017-04-06": "4",
  "2017-04-07": "5",
  "2017-04-01": "6",
  "2017-04-02": "0",
  "2017-04-03": "1",
  "2017-04-10": "1",
  "2017-02-07": "2",
  "2017-02-06": "1",
  "2017-02-09": "4",
  "2017-02-08": "3",
  "2017-03-29": "3",
  "2017-03-25": "6",
  "2017-03-26": "0",
  "2017-03-27": "1",
  "2017-02-01": "3",
  "2017-03-28": "2",
  "2017-03-21": "2",
  "2017-02-03": "5",
  "2017-03-22": "3",
  "2017-02-02": "4",
  "2017-03-23": "4",
  "2017-02-05": "0",
  "2017-03-24": "5",
  "2017-02-04": "6",
  "2017-03-31": "5",
  "2017-03-30": "4",
  "2017-04-23": "0",
  "2017-04-22": "6",
  "2017-02-19": "0",
  "2017-04-25": "2",
  "2017-02-18": "6",
  "2017-04-24": "1",
  "2017-02-17": "5",
  "2017-04-27": "4",
  "2017-04-26": "3",
  "2017-04-29": "6",
  "2017-03-18": "6",
  "2017-04-28": "5",
  "2017-03-19": "0",
  "2017-02-12": "0",
  "2017-03-16": "4",
  "2017-02-11": "6",
  "2017-03-17": "5",
  "2017-02-10": "5",
  "2017-03-14": "2",
  "2017-03-15": "3",
  "2017-02-16": "4",
  "2017-03-12": "0",
  "2017-02-15": "3",
  "2017-03-13": "1",
  "2017-02-14": "2",
  "2017-03-10": "5",
  "2017-02-13": "1",
  "2017-03-11": "6",
  "2017-03-20": "1",
  "2017-03-09": "4",
  "2017-03-08": "3",
  "2017-03-07": "2",
  "2017-03-06": "1",
  "2017-03-05": "0",
  "2017-03-04": "6",
  "2017-03-03": "5",
  "2017-03-02": "4",
  "2017-04-30": "0",
  "2017-03-01": "3"
}
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{
  "3": [
    "2017-04-19",
    "2017-04-12",
    "2017-02-22",
    "2017-04-05",
    "2017-02-08",
    "2017-03-29",
    "2017-02-01",
    "2017-03-22",
    "2017-04-26",
    "2017-03-15",
    "2017-02-15",
    "2017-03-08",
    "2017-03-01"
  ],
  "2": [
    "2017-02-28",
    "2017-04-18",
    "2017-02-21",
    "2017-04-11",
    "2017-04-04",
    "2017-02-07",
    "2017-03-28",
    "2017-03-21",
    "2017-04-25",
    "2017-03-14",
    "2017-02-14",
    "2017-03-07"
  ],
  "1": [
    "2017-04-17",
    "2017-02-27",
    "2017-02-20",
    "2017-04-03",
    "2017-04-10",
    "2017-02-06",
    "2017-03-27",
    "2017-04-24",
    "2017-03-13",
    "2017-02-13",
    "2017-03-20",
    "2017-03-06"
  ],
  "0": [
    "2017-04-16",
    "2017-02-26",
    "2017-04-09",
    "2017-04-02",
    "2017-03-26",
    "2017-02-05",
    "2017-04-23",
    "2017-02-19",
    "2017-03-19",
    "2017-02-12",
    "2017-03-12",
    "2017-03-05",
    "2017-04-30"
  ],
  "6": [
    "2017-02-25",
    "2017-04-15",
    "2017-04-08",
    "2017-04-01",
    "2017-03-25",
    "2017-02-04",
    "2017-04-22",
    "2017-02-18",
    "2017-04-29",
    "2017-03-18",
    "2017-02-11",
    "2017-03-11",
    "2017-03-04"
  ],
  "5": [
    "2017-02-24",
    "2017-04-14",
    "2017-04-21",
    "2017-04-07",
    "2017-02-03",
    "2017-03-24",
    "2017-03-31",
    "2017-02-17",
    "2017-04-28",
    "2017-03-17",
    "2017-02-10",
    "2017-03-10",
    "2017-03-03"
  ],
  "4": [
    "2017-04-13",
    "2017-02-23",
    "2017-04-20",
    "2017-04-06",
    "2017-02-09",
    "2017-02-02",
    "2017-03-23",
    "2017-03-30",
    "2017-04-27",
    "2017-03-16",
    "2017-02-16",
    "2017-03-09",
    "2017-03-02"
  ]
}

总结

本文通过代码示例向大家展示了日期工具类的几种用法,希望对大家学习Java有所帮助。如有不足之处,欢迎留言指出,小编会及时回复大家并更正。感谢朋友们对服务器之家网站的支持!

原文链接:http://blog.csdn.net/l1028386804/article/details/64926588