Java日期处理工具类DateUtils详解
本文实例为大家分享了Java日期处理工具类DateUtils的具体代码，供大家参考，具体内容如下
import java.sql.Timestamp;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
/**
* <日期时间处理工具类>
*/
public class DateUtils {
/**
* Date format pattern this is often used.
*/
public static final String PATTERN_YMD = "yyyy-MM-dd";
/**
* Date format pattern this is often used.
*/
public static final String PATTERN_YMDHMS="yyyy-MM-dd HH:mm:ss";
/**
* Formats the given date according to the YMD pattern.
*
* @param date The date to format.
* @return An YMD formatted date string.
*
* @see #PATTERN_YMD
*/
public static String formatDate(Date date) {
return formatDate(date, PATTERN_YMD);
}
/**
* Formats the given date according to the specified pattern. The pattern
* must conform to that used by the {@link SimpleDateFormat simple date
* format} class.
*
* @param date The date to format.
* @param pattern The pattern to use for formatting the date.
* @return A formatted date string.
*
* @throws IllegalArgumentException If the given date pattern is invalid.
*
* @see SimpleDateFormat
*/
public static String formatDate(Date date, String pattern) {
if (date == null)
throw new IllegalArgumentException("date is null");
if (pattern == null)
throw new IllegalArgumentException("pattern is null");
SimpleDateFormat formatter = new SimpleDateFormat(pattern);
return formatter.format(date);
}
/**
* Parses a date value. The format used for parsing the date value are retrieved from
* the default PATTERN_YMD.
*
* @param dateValue the date value to parse
*
* @return the parsed date
*
* @throws IllegalArgumentException If the given dateValue is invalid.
*/
public static Date parseDate(String dateValue) {
return parseDate(dateValue, null);
}
/**
* Parses the date value using the given date format.
*
* @param dateValue the date value to parse
* @param dateFormat the date format to use
*
* @return the parsed date. if parse is failed , return null
*
* @throws IllegalArgumentException If the given dateValue is invalid.
*/
public static Date parseDate(String dateValue, String dateFormat) {
if (dateValue == null) {
throw new IllegalArgumentException("dateValue is null");
}
if (dateFormat == null) {
dateFormat = PATTERN_YMD;
}
SimpleDateFormat df = new SimpleDateFormat(dateFormat);
Date result = null;
try {
result = df.parse(dateValue);
}
catch (ParseException pe) {
pe.printStackTrace();// 日期型字符串格式错误
}
return result;
}
/**
* Adds a number of years to a date returning a new object.
* The original date object is unchanged.
*
* @param date the date, not null
* @param amount the amount to add, may be negative
* @return the new date object with the amount added
* @throws IllegalArgumentException if the date is null
*/
public static Date addYears(Date date, int amount) {
return add(date, Calendar.YEAR, amount);
}
/**
* Adds a number of years to a timestamp returning a new object.
* The original timestamp object is unchanged.
*
* @param timestamp the timestamp, not null
* @param amount the amount to add, may be negative
* @return the new timestamp object with the amount added
* @throws IllegalArgumentException if the timestamp is null
*/
public static Timestamp addYears(Timestamp timestamp, int amount) {
return add(timestamp, Calendar.YEAR, amount);
}
//-----------------------------------------------------------------------
/**
* Adds a number of months to a date returning a new object.
* The original date object is unchanged.
*
* @param date the date, not null
* @param amount the amount to add, may be negative
* @return the new date object with the amount added
* @throws IllegalArgumentException if the date is null
*/
public static Date addMonths(Date date, int amount) {
return add(date, Calendar.MONTH, amount);
}
/**
* Adds a number of months to a timestamp returning a new object.
* The original timestamp object is unchanged.
*
* @param timestamp the timestamp, not null
* @param amount the amount to add, may be negative
* @return the new timestamp object with the amount added
* @throws IllegalArgumentException if the timestamp is null
*/
public static Timestamp addMonths(Timestamp timestamp, int amount) {
return add(timestamp, Calendar.MONTH, amount);
}
//-----------------------------------------------------------------------
/**
* Adds a number of days to a date returning a new object.
* The original date object is unchanged.
*
* @param date the date, not null
* @param amount the amount to add, may be negative
* @return the new date object with the amount added
* @throws IllegalArgumentException if the date is null
*/
public static Date addDays(Date date, int amount) {
return add(date, Calendar.DATE, amount);
}
/**
* Adds a number of days to a timestamp returning a new object.
* The original timestamp object is unchanged.
*
* @param timestamp the timestamp, not null
* @param amount the amount to add, may be negative
* @return the new timestamp object with the amount added
* @throws IllegalArgumentException if the timestamp is null
*/
public static Timestamp addDays(Timestamp timestamp, int amount) {
return add(timestamp, Calendar.DATE, amount);
}
//-----------------------------------------------------------------------
/**
* Adds a number of minutes to a timestamp returning a new object.
* The original timestamp object is unchanged.
*
* @param timestamp the timestamp, not null
* @param amount the amount to add, may be negative
* @return the new timestamp object with the amount added
* @throws IllegalArgumentException if the timestamp is null
*/
public static Timestamp addMinutes(Timestamp timestamp, int amount) {
return add(timestamp, Calendar.MINUTE, amount);
}
/**
* Adds a number of days to current time returning a new object.
*
* @param amount the amount to add, may be negative
* @return the new timestamp object with the amount added
*/
public static Timestamp addDays(int amount) {
Calendar c = Calendar.getInstance();
c.add(Calendar.DATE, amount);
return new Timestamp(c.getTimeInMillis());
}
//-----------------------------------------------------------------------
/**
* Adds to a date returning a new object.
* The original date object is unchanged.
*
* @param date the date, not null
* @param calendarField the calendar field to add to
* @param amount the amount to add, may be negative
* @return the new date object with the amount added
* @throws IllegalArgumentException if the date is null
*/
private static Date add(Date date, int calendarField, int amount) {
if (date == null) {
throw new IllegalArgumentException("The date must not be null");
}
Calendar c = Calendar.getInstance();
c.setTime(date);
c.add(calendarField, amount);
return c.getTime();
}
/**
* Adds to a timestamp returning a new object.
* The original timestamp object is unchanged.
*
* @param timestamp the timestamp, not null
* @param calendarField the calendar field to add to
* @param amount the amount to add, may be negative
* @return the new timestamp object with the amount added
* @throws IllegalArgumentException if the timestamp is null
*/
private static Timestamp add(Timestamp timestamp, int calendarField, int amount) {
if (timestamp == null) {
throw new IllegalArgumentException("The timestamp must not be null");
}
Calendar c = Calendar.getInstance();
c.setTime(timestamp);
c.add(calendarField, amount);
return new Timestamp(c.getTimeInMillis());
}
/**
* <生成最小的当天日期值>
* @return 最小的当天日期值
*/
public static Timestamp now() {
Calendar c = Calendar.getInstance();
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
return new Timestamp(c.getTimeInMillis());
}
/** This class should not be instantiated. */
private DateUtils() {
}
}
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