Android & Java DateUtils 拿来就用 包含常用的日期和时间转换的工具

public class DateUtils2 {
// private static String defaultDatePattern = "yyyy-MM-dd ";
// private static String defaultDatePattern = "yyyyMMddHHmmssSSSZ";
private static String defaultDatePattern = "yyyyMMddHHmmss";

/**
* 获得默认的 date pattern
*/
public static String getDatePattern() {
return defaultDatePattern;
}

/**
* 返回预设Format的当前日期字符串
*/
public static String getToday() {
Date today = new Date();
return format(today);
}

/**
* 使用预设Format格式化Date成字符串
*/
public static String format(Date date) {
return date == null ? " " : format(date, getDatePattern());
}

/**
* 使用参数Format格式化Date成字符串
*/
public static String format(Date date, String pattern) {
return date == null ? " " : new SimpleDateFormat(pattern).format(date);
}

/**
* 使用预设格式将字符串转为Date
*/
public static Date parse(String strDate) throws ParseException {
return StringUtils.isEmpty(strDate) ? null : parse(strDate,
getDatePattern());
}

/**
* 使用参数Format将字符串转为Date
*/
public static Date parse(String strDate, String pattern) throws ParseException {
return StringUtils.isEmpty(strDate) ? null : new SimpleDateFormat(
pattern).parse(strDate);
}

/**
* 在日期上增加数个整月
*/
public static Date addMonth(Date date, int n) {
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.add(Calendar.MONTH, n);
return cal.getTime();
}

public static String getLastDayOfMonth(String year, String month) {
Calendar cal = Calendar.getInstance();
// 年
cal.set(Calendar.YEAR, Integer.parseInt(year));
// 月，因为Calendar里的月是从0开始，所以要-1
// cal.set(Calendar.MONTH, Integer.parseInt(month) - 1);
// 日，设为一号
cal.set(Calendar.DATE, 1);
// 月份加一，得到下个月的一号
cal.add(Calendar.MONTH, 1);
// 下一个月减一为本月最后一天
cal.add(Calendar.DATE, -1);
return String.valueOf(cal.get(Calendar.DAY_OF_MONTH));// 获得月末是几号
}

public static Date getDate(String year, String month, String day)
throws ParseException {
String result = year + "- " + (month.length() == 1 ? ("0 " + month) : month) + "- " + (day.length() == 1 ? ("0 " + day) : day);
return parse(result);
}

// 获取当天的开始时间
public static java.util.Date getDayBegin() {
Calendar cal = new GregorianCalendar();
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
return cal.getTime();
}

// 获取当天的结束时间
public static java.util.Date getDayEnd() {
Calendar cal = new GregorianCalendar();
cal.set(Calendar.HOUR_OF_DAY, 23);
cal.set(Calendar.MINUTE, 59);
cal.set(Calendar.SECOND, 59);
return cal.getTime();
}

// 获取昨天的开始时间
public static Date getBeginDayOfYesterday() {
Calendar cal = new GregorianCalendar();
cal.setTime(getDayBegin());
cal.add(Calendar.DAY_OF_MONTH, -1);
return cal.getTime();
}

// 获取昨天的结束时间
public static Date getEndDayOfYesterDay() {
Calendar cal = new GregorianCalendar();
cal.setTime(getDayEnd());
cal.add(Calendar.DAY_OF_MONTH, -1);
return cal.getTime();
}

// 获取明天的开始时间
public static Date getBeginDayOfTomorrow() {
Calendar cal = new GregorianCalendar();
cal.setTime(getDayBegin());
cal.add(Calendar.DAY_OF_MONTH, 1);

return cal.getTime();
}

// 获取明天的结束时间
public static Date getEndDayOfTomorrow() {
Calendar cal = new GregorianCalendar();
cal.setTime(getDayEnd());
cal.add(Calendar.DAY_OF_MONTH, 1);
return cal.getTime();
}

// 获取本周的开始时间
public static Date getBeginDayOfWeek() {
Date date = new Date();
Calendar cal = Calendar.getInstance();
cal.setTime(date);
int dayofweek = cal.get(Calendar.DAY_OF_WEEK);
if (dayofweek == 1) {
dayofweek += 7;
}
cal.add(Calendar.DATE, 2 - dayofweek);
return getDayStartTime(cal.getTime());
}

// 获取本周的结束时间
public static Date getEndDayOfWeek() {
Calendar cal = Calendar.getInstance();
cal.setTime(getBeginDayOfWeek());
cal.add(Calendar.DAY_OF_WEEK, 6);
Date weekEndSta = cal.getTime();
return getDayEndTime(weekEndSta);
}

// 获取本月的开始时间
public static Date getBeginDayOfMonth() {
Calendar calendar = Calendar.getInstance();
calendar.set(getNowYear(), getNowMonth() - 1, 1);
return getDayStartTime(calendar.getTime());
}

// 获取本月的结束时间
public static Date getEndDayOfMonth() {
Calendar calendar = Calendar.getInstance();
calendar.set(getNowYear(), getNowMonth() - 1, 1);
int day = calendar.getActualMaximum(5);
calendar.set(getNowYear(), getNowMonth() - 1, day);
return getDayEndTime(calendar.getTime());
}

// 获取本年的开始时间
public static java.util.Date getBeginDayOfYear() {
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, getNowYear());
// cal.set
cal.set(Calendar.MONTH, Calendar.JANUARY);
cal.set(Calendar.DATE, 1);

return getDayStartTime(cal.getTime());
}

// 获取本年的结束时间
public static java.util.Date getEndDayOfYear() {
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, getNowYear());
cal.set(Calendar.MONTH, Calendar.DECEMBER);
cal.set(Calendar.DATE, 31);
return getDayEndTime(cal.getTime());
}

// 获取某个日期的开始时间
public static Timestamp getDayStartTime(Date d) {
Calendar calendar = Calendar.getInstance();
if (null != d)
calendar.setTime(d);
calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),
calendar.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
calendar.set(Calendar.MILLISECOND, 0);
return new Timestamp(calendar.getTimeInMillis());
}

// 获取某个日期的结束时间
public static Timestamp getDayEndTime(Date d) {
Calendar calendar = Calendar.getInstance();
if (null != d)
calendar.setTime(d);
calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),
calendar.get(Calendar.DAY_OF_MONTH), 23, 59, 59);
calendar.set(Calendar.MILLISECOND, 999);
return new Timestamp(calendar.getTimeInMillis());
}

// 获取今年是哪一年
public static Integer getNowYear() {
Date date = new Date();
GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
gc.setTime(date);
return Integer.valueOf(gc.get(1));
}

// 获取本月是哪一月
public static int getNowMonth() {
Date date = new Date();
GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
gc.setTime(date);
return gc.get(2) + 1;
}

// 两个日期相减得到的天数
public static int getDiffDays(Date beginDate, Date endDate) {

if (beginDate == null || endDate == null) {
throw new IllegalArgumentException("getDiffDays param is null!");
}
long diff = (endDate.getTime() - beginDate.getTime()) / (1000 * 60 * 60 * 24);
int days = new Long(diff).intValue();

return days;
}

// 两个日期相减得到的毫秒数
public static long dateDiff(Date beginDate, Date endDate) {
long date1ms = beginDate.getTime();
long date2ms = endDate.getTime();
return date2ms - date1ms;
}

// 获取两个日期中的最大日期
public static Date max(Date beginDate, Date endDate) {
if (beginDate == null) {
return endDate;
}
if (endDate == null) {
return beginDate;
}
if (beginDate.after(endDate)) {
return beginDate;
}
return endDate;
}

// 获取两个日期中的最小日期
public static Date min(Date beginDate, Date endDate) {
if (beginDate == null) {
return endDate;
}
if (endDate == null) {
return beginDate;
}
if (beginDate.after(endDate)) {
return endDate;
}
return beginDate;
}

// 返回某月该季度的第一个月
public static Date getFirstSeasonDate(Date date) {
final int[] SEASON = { 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4 };
Calendar cal = Calendar.getInstance();
cal.setTime(date);
int sean = SEASON[cal.get(Calendar.MONTH)];
cal.set(Calendar.MONTH, sean * 3 - 3);
return cal.getTime();
}

// 返回某个日期下几天的日期
public static Date getNextDay(Date date, int i) {
Calendar cal = new GregorianCalendar();
cal.setTime(date);
cal.set(Calendar.DATE, cal.get(Calendar.DATE) + i);
return cal.getTime();
}

// 返回某个日期前几天的日期
public static Date getFrontDay(Date date, int i) {
Calendar cal = new GregorianCalendar();
cal.setTime(date);
cal.set(Calendar.DATE, cal.get(Calendar.DATE) - i);
return cal.getTime();
}

// 获取某年某月到某年某月按天的切片日期集合（间隔天数的集合）
public static List getTimeList(int beginYear, int beginMonth, int endYear,
int endMonth, int k) {
List list = new ArrayList();
if (beginYear == endYear) {
for (int j = beginMonth; j <= endMonth; j++) {
list.add(getTimeList(beginYear, j, k));
}
} else {
{
for (int j = beginMonth; j < 12; j++) {
list.add(getTimeList(beginYear, j, k));
}

for (int i = beginYear + 1; i < endYear; i++) {
for (int j = 0; j < 12; j++) {
list.add(getTimeList(i, j, k));
}
}
for (int j = 0; j <= endMonth; j++) {
list.add(getTimeList(endYear, j, k));
}
}
}
return list;
}

// 获取某年某月按天切片日期集合（某个月间隔多少天的日期集合）
public static List getTimeList(int beginYear, int beginMonth, int k) {
List list = new ArrayList();
Calendar begincal = new GregorianCalendar(beginYear, beginMonth, 1);
int max = begincal.getActualMaximum(Calendar.DATE);
for (int i = 1; i < max; i = i + k) {
list.add(begincal.getTime());
begincal.add(Calendar.DATE, k);
}
begincal = new GregorianCalendar(beginYear, beginMonth, max);
list.add(begincal.getTime());
return list;
}

/**
* 根据提供的年月日获取该月份的第一天
* @Description: (这里用一句话描述这个方法的作用)
* @Author: gyz
* @Since: 2017-1-9下午2:26:57
* @param year
* @param monthOfYear
* @return
*/
public static Date getSupportBeginDayofMonth(int year, int monthOfYear) {
Calendar cal = Calendar.getInstance();
// 不加下面2行，就是取当前时间前一个月的第一天及最后一天
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, monthOfYear);
cal.set(Calendar.DAY_OF_MONTH, 1);
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);

cal.add(Calendar.DAY_OF_MONTH, -1);
Date lastDate = cal.getTime();

cal.set(Calendar.DAY_OF_MONTH, 1);
Date firstDate = cal.getTime();
return firstDate;
}

/**
* 根据提供的年月获取该月份的最后一天
* @Description: (这里用一句话描述这个方法的作用)
* @Author: gyz
* @Since: 2017-1-9下午2:29:38
* @param year
* @param monthOfYear
* @return
*/
public static Date getSupportEndDayofMonth(int year, int monthOfYear) {
Calendar cal = Calendar.getInstance();
// 不加下面2行，就是取当前时间前一个月的第一天及最后一天
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, monthOfYear);
cal.set(Calendar.DAY_OF_MONTH, 1);
cal.set(Calendar.HOUR_OF_DAY, 23);
cal.set(Calendar.MINUTE, 59);
cal.set(Calendar.SECOND, 59);

cal.add(Calendar.DAY_OF_MONTH, -1);
Date lastDate = cal.getTime();

cal.set(Calendar.DAY_OF_MONTH, 1);
Date firstDate = cal.getTime();
return lastDate;
}
}