本文介紹了Java開發過程中日期相關操作，分享的代碼如下：
package jse; import java.io.UnsupportedEncodingException;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.Locale; /** * 常用日期操作* * @author puck * createDate 2015-07-30 22:54:38 */public class TestDate{ public static void main(String[] args) throws ParseException, UnsupportedEncodingException { Calendar cal = Calendar.getInstance();/ / cal.add(Calendar.DAY_OF_MONTH, -48); System.out.println(dateToString(cal)); } /** * 日期格式化* @param date * @return */ public static String dateToString(Date date) {// SimpleDateFormat format = new SimpleDateFormat("y年MM月dd日E HH時mm分ss秒", Locale.CHINA);// SimpleDateFormat format = new SimpleDateFormat("y年M月d日EH時m分s秒", Locale.CHINA); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.CHINA); // example return sdf.format(date); } /** * 日期格式化* @param date * @return */ public static String dateToString(Calendar cal) { return dateToString(cal.getTime()); } /** * dateString 轉Calendar * * @param Date * format:2015-06-16 date * @return Calendar * @throws ParseException */ public static Calendar dateStringToCalendar(String dateStr) throws ParseException {// Calendar cal = Calendar.getInstance();// cal.clear();// cal.set(Integer.parseInt (date.substring(0, 4)), Integer.parseInt(date.substring(5, 7)) - 1,// Integer.parseInt(date.substring(8, 10)));// return cal; SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date date = sdf.parse(dateStr); Calendar cal = Calendar.getInstance(); cal.setTime(date); return cal; } / ** * dateString 轉Date * * @param Date * format:yyyy-MM-dd HH:mm:ss date * @return Calendar * @throws ParseException */ public static Date dateStringToDate(String date) throws ParseException { SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); return sdf.parse(date); } /** * Date Convert to Calendar * * @param date * @return */ public static Calendar dateToCalendar(Date date ) { Calendar c1 = Calendar.getInstance(); c1.setTime(date); return c1; } /** * Calendar Convert To Date * @param cal * @return */ public static Date CalendarToDate(Calendar cal) { return cal .getTime(); } /** * 計算兩個日期相差年月日* * @param Date * c1 * @param Date * c2 * @return int[]{year, month, day} */ public int[] calculateDifferDay(Date d1, Date d2) { Calendar c1 = Calendar.getInstance(); c1.setTime(d1); Calendar c2 = Calendar.getInstance(); c1.setTime(d2); return calculateDifferDay(c1, c2); } /** * 計算兩個日期相差年月日* * @param Calendar * c1 * @param Calendar * c2 * @return int[]{year, month, day} */ public int[] calculateDifferDay(Calendar c1, Calendar c2) { int[] p1 = { c1.get(Calendar.YEAR), c1.get(Calendar.MONTH), c1.get(Calendar.DAY_OF_MONTH) }; int[] p2 = { c2.get(Calendar.YEAR ), c2.get(Calendar.MONTH), c2.get(Calendar.DAY_OF_MONTH) }; System.out.println("p1[0]=" + p1[0] + " p1[1]=" + p1[ 1] + " p1[2]=" + p1[2]); System.out.println("p2[0]=" + p2[0] + " p2[1]=" + p2[1] + " p2[2]=" + p2[2]); int year = p2[0] - p1[0]; int month = (p2[0] * 12) + p2[1] - ((p1[0] * 12) + p1[1]); int day = (int) ((c2.getTimeInMillis() - c1.getTimeInMillis()) / (24 * 60 * 60 * 1000)); return new int[] { year, month , day }; } /** * 獲取日期所在周的第一天* * @param c * @return */ public static Calendar getLastDayOfWeek(Calendar c) {// SimpleDateFormat format2 = new SimpleDateFormat("y年M月d日EH時m分s秒", Locale.CHINA);// System.out.println("當前時間:" + format2.format(c.getTime())); c.set(Calendar.DAY_OF_WEEK, Calendar. MONDAY);// System.out.println("週一時間:" + format2.format(c.getTime())); return c; } /** * 日期加減* @param c * @param day * @ return */ public static Calendar addOrDecreaseDay(Calendar c, int day) { c.add(Calendar.DAY_OF_MONTH, day); return c; } /** * 獲取月最後一天* @param year * @param month * @return * / public static int getLastDayOfMonth(int year, int month) { Calendar c = Calendar.getInstance(); c.set(year, month - 1, 1); return c.getActualMaximum(Calendar.DAY_OF_MONTH); } /** *獲取月最後一天* @param cal * @return */ public static int getLastDayOfMonth(Calendar cal) { return cal.getActualMaximum(Calendar.DAY_OF_MONTH); } }