项目常用工具类整理（一）--时间工具类DateUtil.java

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class DateUtil {
	/**
	 * 比较日期大小
	 * @param dateStr0
	 * @param dateStr1
	 * @return
	 */
	public static int compareDate(String dateStr0, String dateStr1) {
		Date date1 = convertDateStrToDate(dateStr0, "datetime");
		Date date2 = convertDateStrToDate(dateStr1, "datetime");
		int result = date1.compareTo(date2);
		return result;
	}
	
	/**
	 * 格式化日期
	 * @param date
	 * @param pattern
	 * 		"date":返回日期(yyyy-MM-dd)
	 * 		"time":返回时间(HH:mm:ss)
	 * 		"datetime":返回日期和时间(yyyy-MM-dd HH:mm:ss)
	 * @return
	 */
	public static String formatDate(Date date, String pattern) {
		if (date == null) {
			return "";
		}
		
		if ("date".equals(pattern)) {
			pattern = "yyyy-MM-dd";
		} else if ("time".equals(pattern)) {
			pattern = "HH:mm:ss";
		} else if ("datetime".equals(pattern)) {
			pattern = "yyyy-MM-dd HH:mm:ss";
		}
		
		SimpleDateFormat formatter = new SimpleDateFormat(pattern);
		return formatter.format(date);
	}
	
	/**
	 * 格式化日期字符串
	 * @param dateStr
	 * @param type
	 * 		"date":返回日期(yyyy-MM-dd)
	 * 		"time":返回时间(HH:mm:ss)
	 * 		"datetime":返回日期和时间(yyyy-MM-dd HH:mm:ss)
	 * @return
	 */
	public static String formatDate(String dateStr, String type) {
		if (dateStr == null || "".equals(dateStr.trim())) {
			return "";
		}
		
		DateFormat formatter = DateFormat.getDateInstance();
		Date date = null;
		try {
			date = formatter.parse(dateStr);
		} catch (ParseException e) {
			e.printStackTrace();
		}
		return formatDate(date, type);
	}
	
	/**
	 * 把日期字符串转换成日期
	 * @param dateStr
	 * 		日期字符串
	 * @param pattern
	 * 		"date":日期,
	 * 		"datetime":日期和时间
	 * @return
	 */
	public static Date convertDateStrToDate(String dateStr, String pattern) {
		if (dateStr == null || "".equals(dateStr.trim())) {
			return null;
		}
		if (!dateStr.contains(":")) {
			dateStr += " 00:00:00";
		}
		
		if ("date".equals(pattern)) {
			pattern = "yyyy-MM-dd";
		} else if ("datetime".equals(pattern)) {
			pattern = "yyyy-MM-dd HH:mm:ss";
		}
		SimpleDateFormat formatter = new SimpleDateFormat(pattern);
		Date date = null;
		try {
			date = formatter.parse(dateStr);
		} catch (ParseException e) {
			e.printStackTrace();
		}
		return date;
	}
	
	/**
	 * 获取当前时间
	 * @return
	 */
	public static Date getCurrTime() {
		return new Date();
	}
	
	/**
	 * 获取当前时间
	 * @param pattern
	 * 		"date":返回日期(yyyy-MM-dd),
	 * 		"time":返回时间(HH:mm:ss),
	 * 		"datetime":返回日期和时间(yyyy-MM-dd HH:mm:ss)
	 * @return
	 */
	public static String getCurrTime(String pattern) {
		return formatDate(new Date(), pattern);
	}
	
	/**
	 * 获取中文格式当前日期
	 * @param pattern
	 * 		"long":1984年10月9日
	 * 		"full":1984年10月9日 星期二
	 * @return
	 */
	public static String getCurrDateCN(String pattern) {
		Calendar calendar = Calendar.getInstance();
		int year = calendar.get(Calendar.YEAR);
		int month = calendar.get(Calendar.MONTH) + 1;
		int day = calendar.get(Calendar.DAY_OF_MONTH);
		
		if ("long".equals(pattern)) {
			return year + "年" + month + "月" + day + "日";
		}
		if ("full".equals(pattern)) {
			return year + "年" + month + "月" + day + "日 " + getDayCN(calendar.getTime());
		}
		return "";
	}
	
	/**
	 * 在原日期加一段时间间隔
	 * @param date
	 * 		原日期
	 * @param field
	 * 		"yyyy":年
	 * 		"MM":月
	 * 		"dd":日
	 * @param amount
	 * 		间隔长度
	 * @return
	 */
	public static Date dateAdd(Date date, String field, int amount) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		
		if ("yyyy".equals(field)) {
			calendar.add(Calendar.YEAR, amount);
		} else if ("MM".equals(field)) {
			calendar.add(Calendar.MONTH, amount);
		} else if ("dd".equals(field)) {
			calendar.add(Calendar.DATE, amount);
		}
		return calendar.getTime();
	}
	
	/**
	 * 在原日期加一段时间间隔
	 * @param date
	 * 		原日期
	 * @param field
	 * 		"yyyy":年
	 * 		"MM":月
	 * 		"dd":日
	 * @param amount
	 * 		间隔长度
	 * @param pattern
	 * 		"date":返回日期(yyyy-MM-dd),
	 * 		"time":返回时间(HH:mm:ss),
	 * 		"datetime":返回日期和时间(yyyy-MM-dd HH:mm:ss)
	 * @return
	 */
	public static String dateAdd(String dateStr, String field, int amount, String pattern) {
		if (Tools.isEmpty(dateStr)) {
			return "";
		}
		
		Date date = convertDateStrToDate(dateStr, "datetime");
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		if ("yyyy".equals(field)) {
			calendar.add(Calendar.YEAR, amount);
		} else if ("MM".equals(field)) {
			calendar.add(Calendar.MONTH, amount);
		} else if ("dd".equals(field)) {
			calendar.add(Calendar.DATE, amount);
		}
		date = calendar.getTime();
		dateStr = formatDate(date, pattern);
		return dateStr;
	}
	
	/**
	 * 计算日期差
	 * @param date1
	 * @param date2
	 * @param field
	 * 		yyyy:年
	 * 		MM:月
	 * 		dd:日
	 * @return
	 * 		date2 - date1
	 */
	public static int dateDiff(Date date1, Date date2, String field) {
		boolean flag = date1.compareTo(date2) > 0;
		if (flag) {
			Date tmp = date1;
			date1 = date2;
			date2 = tmp;
		}
		
		Calendar cal1 = Calendar.getInstance();
		cal1.setTime(date1);
		int year1 = cal1.get(Calendar.YEAR);
		int month1 = cal1.get(Calendar.MONTH);
		Calendar cal2 = Calendar.getInstance();
		cal2.setTime(date2);
		int year2 = cal2.get(Calendar.YEAR);
		int month2 = cal2.get(Calendar.MONTH);
		int yearDiff = year2- year1;
		
		int diff = 0;
		if ("yyyy".equals(field)) {
			diff = yearDiff;
		} else if ("MM".equals(field)) {
			if (yearDiff <= 0) {
				diff = month2 - month1;
			} else if (yearDiff == 1) {
				diff = 12 - month1 + month2;
			} else {
				diff = 12 - month1 + (year2 - year1 - 1) * 12 + month2;
			}
		} else if ("dd".equals(field)) {
			if (yearDiff <= 0) {
				diff = cal2.get(Calendar.DAY_OF_YEAR) - cal1.get(Calendar.DAY_OF_YEAR);
			} else if (yearDiff == 1) {
				diff = getDaysLeftOfYear(date1) + cal2.get(Calendar.DAY_OF_YEAR);
			} else {
				diff = getDaysLeftOfYear(date1);
				Calendar cal;
				for (int i = 1; i < yearDiff; i++) {
					cal = Calendar.getInstance();
					cal.setTime(dateAdd(date1, "yyyy", i));
					diff += cal.getActualMaximum(Calendar.DAY_OF_YEAR);
				}
				diff += cal2.get(Calendar.DAY_OF_YEAR);
			}
		}
		
		return flag ? -1 * diff : diff;
	}
	
	/**
	 * 计算日期差
	 * @param date1
	 * @param date2
	 * @param field
	 * 		yyyy:年
	 * 		MM:月
	 * 		dd:日
	 * @return
	 */
	public static int dateDiff(String dateStr1, String dateStr2, String field) {
		Date date1 = convertDateStrToDate(dateStr1, "date");
		Date date2 = convertDateStrToDate(dateStr2, "date");
		int dateDiff = dateDiff(date1, date2, field);
		return dateDiff;
	}
	
	/**
	 * 是否闰年
	 * @param year
	 * @return
	 */
	public static boolean isLeapYear(int year) {
		boolean flag = (year % 4 == 0 && year % 100 != 0) || year % 400 == 0;
		return flag;
	}
	
	/**
	 * 是否闰年
	 * @param date
	 * @return
	 */
	public static boolean isLeapYear(Date date) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		boolean flag = isLeapYear(cal.get(Calendar.YEAR));
		return flag;
	}
	
	/**
	 * 计算给定日期当年总天数
	 * @param date
	 * @return
	 */
	public static int getDaysOfYear(Date date) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		return cal.getActualMaximum(Calendar.DAY_OF_YEAR);
	}
	
	/**
	 * 计算给定日期当年剩余天数
	 * @param date
	 * @return
	 */
	public static int getDaysLeftOfYear(Date date) {
		Calendar cal = Calendar.getInstance();
		cal.setTime(date);
		int cnt = cal.getActualMaximum(Calendar.DAY_OF_YEAR) - cal.get(Calendar.DAY_OF_YEAR);
		return cnt;
	}
	
	/**
	 * 获得星期几(周日为1，周六为7)
	 * @param date
	 * 		给定日期
	 * @return
	 */
	public static int getDay(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		return calendar.get(Calendar.DAY_OF_WEEK);
	}
	
	/**
	 * 获得星期几（中文）
	 * @param date
	 * @return
	 */
	public static String getDayCN(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
		switch (dayOfWeek) {
			case 1:
				return "星期日";
			case 2:
				return "星期一";
			case 3:
				return "星期二";
			case 4:
				return "星期三";
			case 5:
				return "星期四";
			case 6:
				return "星期五";
			case 7:
				return "星期六";
			default:
				return "";
		}
	}
	
	/**
	 * 计算给定日期所在月的第一天
	 * @param date
	 * 		给定日期
	 * @return
	 */
	public static Date getFirstDayOfMonth(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		calendar.set(Calendar.DAY_OF_MONTH, 1);
		return calendar.getTime();
	}
	
	/**
	 * 计算给定日期所在月的最后一天
	 * @param date
	 * 		给定日期
	 * @return
	 */
	public static Date getLastDayOfMonth(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
		return calendar.getTime();
	}
	
	/**
	 * 计算给定日期所在周的第一天(周一)
	 * @param date
	 * 		给定日期
	 * @return
	 */
	public static Date getFirstDayOfWeek(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
		dayOfWeek = dayOfWeek == Calendar.SUNDAY ? 8 : dayOfWeek;
		int dValue = Calendar.MONDAY - dayOfWeek;
		calendar.add(Calendar.DAY_OF_WEEK, dValue);
		return calendar.getTime();
	}
	
	/**
	 * 计算给定日期所在月的最后一天(周日)
	 * @param date
	 * 		给定日期
	 * @return
	 */
	public static Date getLastDayOfWeek(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
		dayOfWeek = dayOfWeek == Calendar.SUNDAY ? 8 : dayOfWeek;
		int diff = 8 - dayOfWeek;
		calendar.add(Calendar.DAY_OF_WEEK, diff);
		return calendar.getTime();
	}
	
	/**
	 * 计算月视图中展示的第一天
	 * @param date
	 * 		给定日期
	 * @return
	 */
	public static Date getFirstDayOfMonthView(Date date) {
		Date firstDayOfMonth = getFirstDayOfMonth(date);
		int dayOfWeek = getDay(firstDayOfMonth);
		int diff = Calendar.SUNDAY - dayOfWeek;
		
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(firstDayOfMonth);
		calendar.add(Calendar.DAY_OF_WEEK, diff);
		return calendar.getTime();
	}
	
	/**
	 * 计算月视图中展示的最后一天
	 * @param date
	 * 		给定日期
	 * @return
	 */
	public static Date getLastDayOfMonthView(Date date) {
		Date lastDayOfMonth = getLastDayOfMonth(date);
		int dayOfWeek = getDay(lastDayOfMonth);
		int diff = Calendar.SATURDAY - dayOfWeek;
		
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(lastDayOfMonth);
		calendar.add(Calendar.DAY_OF_WEEK, diff);
		return calendar.getTime();
	}
	
	/**
	 * 计算月视图展示行数
	 * @param date
	 * @return
	 */
	public static int getRowCntOfMonthView(Date date) {
		int dayOfWeek1 = getDay(getFirstDayOfMonth(date));
		int dayOfWeek2 = getDay(getLastDayOfMonth(date));
		
		if (dayOfWeek1 == Calendar.SUNDAY && dayOfWeek2 == Calendar.SATURDAY) {
			return 4;
		}
		if (dayOfWeek1 != Calendar.SUNDAY && dayOfWeek2 != Calendar.SATURDAY) {
			return 6;
		}
		return 5;
	}
	
	public static void main(String args[]) {
		System.out.println(DateUtil.getCurrDateCN("full"));
		System.out.println(DateUtil.getCurrDateCN("long"));
	}
}