Date工具类

import  java.text.ParsePosition;
import  java.text.SimpleDateFormat;
import  java.util.Calendar;
import  java.util. Date ;
import  java.util.GregorianCalendar;
import  java.util.regex.Pattern;

import  org.apache.commons.logging.Log;
import  org.apache.commons.logging.LogFactory;


public  class  DateUtil {
  protected  static  Log logger = LogFactory.getLog(DateUtil. class );

  // 格式：年－月－日 小时：分钟：秒
  public  static  final  String  FORMAT_ONE =  "yyyy-MM-dd HH:mm:ss" ;

  // 格式：年－月－日 小时：分钟
  public  static  final  String  FORMAT_TWO =  "yyyy-MM-dd HH:mm" ;

  // 格式：年月日 小时分钟秒
  public  static  final  String  FORMAT_THREE =  "yyyyMMdd-HHmmss" ;

  // 格式：年－月－日
  public  static  final  String  LONG_DATE_FORMAT =  "yyyy-MM-dd" ;

  // 格式：月－日
  public  static  final  String  SHORT_DATE_FORMAT =  "MM-dd" ;

  // 格式：小时：分钟：秒
  public  static  final  String  LONG_TIME_FORMAT =  "HH:mm:ss" ;

  //格式：年-月
  public  static  final  String  MONTG_DATE_FORMAT =  "yyyy-MM" ;

  // 年的加减
  public  static  final  int  SUB_YEAR = Calendar.YEAR;

  // 月加减
  public  static  final  int  SUB_MONTH = Calendar.MONTH;

  // 天的加减
  public  static  final  int  SUB_DAY = Calendar.DATE;

  // 小时的加减
  public  static  final  int  SUB_HOUR = Calendar.HOUR;

  // 分钟的加减
  public  static  final  int  SUB_MINUTE = Calendar.MINUTE;

  // 秒的加减
  public  static  final  int  SUB_SECOND = Calendar.SECOND;

  static  final  String  dayNames[] = {  "星期日" ,  "星期一" ,  "星期二" ,  "星期三" , "星期四" ,
      "星期五" ,  "星期六"  };

  @SuppressWarnings( "unused" )
  private  static  final  SimpleDateFormat timeFormat =  new  SimpleDateFormat(
      "yyyy-MM-dd HH:mm:ss" );

  public  DateUtil() {
  }

  /**
   * 把符合日期格式的字符串转换为日期类型
   */
  public  static  java.util. Date  stringtoDate( String  dateStr,  String  format) {
    Date  d =  null ;
    SimpleDateFormat formater =  new  SimpleDateFormat(format);
    try  {
      formater.setLenient( false );
      d = formater.parse(dateStr);
    }  catch  (Exception e) {
      // log.error(e);
      d =  null ;
    }
    return  d;
  }

  /**
   * 把符合日期格式的字符串转换为日期类型
   */
  public  static  java.util. Date  stringtoDate( String  dateStr,  String  format,
      ParsePosition pos) {
    Date  d =  null ;
    SimpleDateFormat formater =  new  SimpleDateFormat(format);
    try  {
      formater.setLenient( false );
      d = formater.parse(dateStr, pos);
    }  catch  (Exception e) {
      d =  null ;
    }
    return  d;
  }

  /**
   * 把日期转换为字符串
   */
  public  static  String  dateToString(java.util. Date  date,  String  format) {
    String  result =  "" ;
    SimpleDateFormat formater =  new  SimpleDateFormat(format);
    try  {
      result = formater.format(date);
    }  catch  (Exception e) {
      // log.error(e);
    }
    return  result;
  }

  /**
   * 获取当前时间的指定格式
   */
  public  static  String  getCurrDate( String  format) {
    return  dateToString( new  Date (), format);
  }

  public  static  String  dateSub( int  dateKind,  String  dateStr,  int  amount) {
    Date  date = stringtoDate(dateStr, FORMAT_ONE);
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    calendar.add(dateKind, amount);
    return  dateToString(calendar.getTime(), FORMAT_ONE);
  }

  /**
   * 两个日期相减
   * @return 相减得到的秒数
   */
  public  static  long timeSub( String  firstTime,  String  secTime) {
    long first = stringtoDate(firstTime, FORMAT_ONE).getTime();
    long second = stringtoDate(secTime, FORMAT_ONE).getTime();
    return  (second - first) /  1000 ;
  }

  /**
   * 获得某月的天数
   */
  public  static  int  getDaysOfMonth( String  year,  String  month) {
    int  days =  0 ;
    if  (month.equals( "1" ) || month.equals( "3" ) || month.equals( "5" )
        || month.equals( "7" ) || month.equals( "8" ) || month.equals( "10" )
        || month.equals( "12" )) {
      days =  31 ;
    }  else  if  (month.equals( "4" ) || month.equals( "6" ) || month.equals( "9" )
        || month.equals( "11" )) {
      days =  30 ;
    }  else  {
      if  ((Integer. parseInt (year) %  4  ==  0  && Integer. parseInt (year) %  100  != 0 )
          || Integer. parseInt (year) %  400  ==  0 ) {
        days =  29 ;
      }  else  {
        days =  28 ;
      }
    }

    return  days;
  }

  /**
   * 获取某年某月的天数
   */
  public  static  int  getDaysOfMonth( int  year,  int  month) {
    Calendar calendar = Calendar.getInstance();
    calendar. set (year, month -  1 ,  1 );
    return  calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
  }

  /**
   * 获得当前日期
   */
  public  static  int  getToday() {
    Calendar calendar = Calendar.getInstance();
    return  calendar. get (Calendar.DATE);
  }

  /**
   * 获得当前月份
   */
  public  static  int  getToMonth() {
    Calendar calendar = Calendar.getInstance();
    return  calendar. get (Calendar.MONTH) +  1 ;
  }

  /**
   * 获得当前年份
   */
  public  static  int  getToYear() {
    Calendar calendar = Calendar.getInstance();
    return  calendar. get (Calendar.YEAR);
  }

  /**
   * 返回日期的天
   */
  public  static  int  getDay( Date  date) {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    return  calendar. get (Calendar.DATE);
  }

  /**
   * 返回日期的年
   */
  public  static  int  getYear( Date  date) {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    return  calendar. get (Calendar.YEAR);
  }

  /**
   * 返回日期的月份，1-12
   */
  public  static  int  getMonth( Date  date) {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    return  calendar. get (Calendar.MONTH) +  1 ;
  }

  /**
   * 计算两个日期相差的天数，如果date2 > date1 返回正数，否则返回负数
   */
  public  static  long dayDiff( Date  date1,  Date  date2) {
    return  (date2.getTime() - date1.getTime()) /  86400000 ;
  }

  /**
   * 比较两个日期的年差
   */
  public  static  int  yearDiff( String  before,  String  after) {
    Date  beforeDay = stringtoDate(before, LONG_DATE_FORMAT);
    Date  afterDay = stringtoDate(after, LONG_DATE_FORMAT);
    return  getYear(afterDay) - getYear(beforeDay);
  }

  /**
   * 比较指定日期与当前日期的差
   */
  public  static  int  yearDiffCurr( String  after) {
    Date  beforeDay =  new  Date ();
    Date  afterDay = stringtoDate(after, LONG_DATE_FORMAT);
    return  getYear(beforeDay) - getYear(afterDay);
  }

  /**
   * 比较指定日期与当前日期的差
   */
  public  static  long dayDiffCurr( String  before) {
    Date  currDate = DateUtil.stringtoDate(currDay(), LONG_DATE_FORMAT);
    Date  beforeDate = stringtoDate(before, LONG_DATE_FORMAT);
    return  (currDate.getTime() - beforeDate.getTime()) /  86400000 ;

  }

  /**
   * 获取每月的第一周
   */
  public  static  int  getFirstWeekdayOfMonth( int  year,  int  month) {
    Calendar c = Calendar.getInstance();
    c.setFirstDayOfWeek(Calendar.SATURDAY);  // 星期天为第一天
    c. set (year, month -  1 ,  1 );
    return  c. get (Calendar.DAY_OF_WEEK);
  }
  /**
   * 获取每月的最后一周
   */
  public  static  int  getLastWeekdayOfMonth( int  year,  int  month) {
    Calendar c = Calendar.getInstance();
    c.setFirstDayOfWeek(Calendar.SATURDAY);  // 星期天为第一天
    c. set (year, month -  1 , getDaysOfMonth(year, month));
    return  c. get (Calendar.DAY_OF_WEEK);
  }

  /**
   * 获得当前日期字符串，格式"yyyy_MM_dd_HH_mm_ss"
   *
   * @return
   */
  public  static  String  getCurrent() {
    Calendar cal = Calendar.getInstance();
    cal.setTime( new  Date ());
    int  year = cal. get (Calendar.YEAR);
    int  month = cal. get (Calendar.MONTH) +  1 ;
    int  day = cal. get (Calendar.DAY_OF_MONTH);
    int  hour = cal. get (Calendar.HOUR_OF_DAY);
    int  minute = cal. get (Calendar.MINUTE);
    int  second = cal. get (Calendar.SECOND);
    StringBuffer sb =  new  StringBuffer();
    sb.append(year).append( "_" ).append(StringUtil.addzero(month,  2 ))
        .append( "_" ).append(StringUtil.addzero(day,  2 )).append( "_" )
        .append(StringUtil.addzero(hour,  2 )).append( "_" ).append(
            StringUtil.addzero(minute,  2 )).append( "_" ).append(
            StringUtil.addzero(second,  2 ));
    return  sb.toString();
  }

  /**
   * 获得当前日期字符串，格式"yyyy-MM-dd HH:mm:ss"
   *
   * @return
   */
  public  static  String  getNow() {
    Calendar today = Calendar.getInstance();
    return  dateToString(today.getTime(), FORMAT_ONE);
  }



  /**
   * 判断日期是否有效,包括闰年的情况
   *
   * @param date
   *     YYYY-mm-dd
   * @return
   */
  public  static  boolean isDate( String  date) {
    StringBuffer reg =  new  StringBuffer(
        "^((\\d{2}(([02468][048])|([13579][26]))-?((((0?" );
    reg.append( "[13578])|(1[02]))-?((0?[1-9])|([1-2][0-9])|(3[01])))" );
    reg.append( "|(((0?[469])|(11))-?((0?[1-9])|([1-2][0-9])|(30)))|" );
    reg.append( "(0?2-?((0?[1-9])|([1-2][0-9])))))|(\\d{2}(([02468][12" );
    reg.append( "35679])|([13579][01345789]))-?((((0?[13578])|(1[02]))" );
    reg.append( "-?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))" );
    reg.append( "-?((0?[1-9])|([1-2][0-9])|(30)))|(0?2-?((0?[" );
    reg.append( "1-9])|(1[0-9])|(2[0-8]))))))" );
    Pattern p = Pattern.compile(reg.toString());
    return  p.matcher(date).matches();
  }