日期相关的工具类

package arithmetic;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;/** * 有关日期时间的工具类 * @author liujd * */public class DataUtil {//格式化"yyyy-MM-dd"private static final String Date_Format_day = "yyyy-MM-dd";//格式化"yyyy-MM-dd HH:mm:ss"private static final String Date_Format_seconds = "yyyy-MM-dd HH:mm:ss";//格式化"yyyy-MM-dd HH:mm:ss"private static final String Date_Format_hms = "HH:mm:ss";/** * 格式化"yyyy-MM-dd" *  * @param Date * @return String */public static String FormatToDay(Date dateNow) {SimpleDateFormat sdf = new SimpleDateFormat(Date_Format_day);return sdf.format(dateNow);}/** * 格式化"yyyy-MM-dd HH:mm:ss" *  * @param Date * @return String  */public static String FormatToSeconds(Date dateNow) {SimpleDateFormat sdf = new SimpleDateFormat(Date_Format_seconds);return sdf.format(dateNow);}/** * 格式化"HH:mm:ss" *  * @param Date * @return String  */public static String FormatHms(Date dateNow) {SimpleDateFormat sdf = new SimpleDateFormat(Date_Format_hms);return sdf.format(dateNow);}/** * 获取年 月 日  时 分 秒 * @param String Date * @return int */@SuppressWarnings("deprecation")public static int getByType(Date dateNow,String type) {int result = 0;switch (type) {case "year":result = dateNow.getYear() + 1900;break;case "month":result = dateNow.getMonth() + 1;break;case "day":result = dateNow.getDate();break;case "hours":result = dateNow.getHours();break;case "minutes":result = dateNow.getMinutes();break;case "seconds":result = dateNow.getSeconds();break;default:result = 0;break;}return result;}/** * 将日期转换为字符串 *  * @param Date * @return String */@SuppressWarnings("deprecation")public static String DateToString(Date dateNow) {return dateNow.toLocaleString();}/** * 将时间格式是 "yyyy-MM-dd HH:mm:ss"的字符串转换为日期 * @param String * @return Date */public static Date StringToDate1(String dateString) {try {SimpleDateFormat sdf = new SimpleDateFormat(Date_Format_seconds);return sdf.parse(dateString);} catch (ParseException e) {e.printStackTrace();return null;}}/** * 将时间格式是 "yyyy-MM-dd"的字符串转换为日期 * @param String * @return Date */public static Date StringToDate2(String dateString)  {try {SimpleDateFormat sdf = new SimpleDateFormat(Date_Format_day);return sdf.parse(dateString);} catch (ParseException e) {e.printStackTrace();return null;}}/** * 获取两个日期相差的天数 * @param Date Date * @return int */public static int diffOfTwo(Date date1 , Date date2) {long time1 = date1.getTime();long time2 = date2.getTime();int diff = (int)((time1-time2)/60*60*24*1000);return diff;}/** * 指定日期加上天数 * @param Date int * @return Date */public static Date addDate(Date date , int day) {Calendar c = Calendar.getInstance();c.setTime(date);long timeInMillis = c.getTimeInMillis();c.setTimeInMillis(timeInMillis+(((long)day)*24*60*60*1000));return c.getTime();}/** * 指定日期减去天数 * @param Date int * @return Date */public static Date subDate(Date date , int day) {Calendar c = Calendar.getInstance();c.setTime(date);long timeInMillis = c.getTimeInMillis();c.setTimeInMillis(timeInMillis-(((long)day)*24*60*60*1000));return c.getTime();}/** * 获取年 * @param Date * @return int */public static int getYear(Date date) {if(date == null) {date = new Date();}Calendar c = Calendar.getInstance();c.setTime(date);return c.get(Calendar.YEAR);}/** * 获取月 * @param Date * @return int */public static int getMonth(Date date) {if(date == null) {date = new Date();}Calendar c = Calendar.getInstance();c.setTime(date);return c.get(Calendar.MONTH) + 1;}/** * 获取日 * @param Date * @return int */public static int getDay(Date date) {if(date == null) {date = new Date();}Calendar c = Calendar.getInstance();c.setTime(date);return c.get(Calendar.DAY_OF_MONTH);}/** * 获取星期 * @param Date * @return int */public static int getWeek(Date date) {if(date == null) {date = new Date();}Calendar c = Calendar.getInstance();c.setTime(date);int week = c.get(Calendar.DAY_OF_WEEK) - 1;if(week == 0) {return 7;}else {return week;}}/** * 判断字符串是否是时间格式 * 默认时间格式是 "yyyy-MM-dd" * @param string * @return boolean */public static boolean isDateFormat(String dateString) {SimpleDateFormat sdf = new SimpleDateFormat(Date_Format_day);if(isEmpty(dateString)) {return false;}try {sdf.parse(dateString);return true;} catch (ParseException e) {e.printStackTrace();return false;}}/** * 判断字符串是否为空 * @param string * @return boolean */public static boolean isEmpty(String str) {return str.trim().length() == 0 ? true : false;}public static void main(String[] args) {System.out.println(FormatToDay(new Date()));;System.out.println(FormatToSeconds(new Date()));;}}

暂时就想到这些  以后补上