datehelper.java

《j2ee经典实例详解》的源代码。原书无附带光盘。介绍的是一个在线银行系统的例子。绝对难得

/*
 * Copyright (c) 2005 Sun Microsystems, Inc.  All rights reserved.  U.S.
 * Government Rights - Commercial software.  Government users are subject
 * to the Sun Microsystems, Inc. standard license agreement and
 * applicable provisions of the FAR and its supplements.  Use is subject
 * to license terms.
 *
 * This distribution may include materials developed by third parties.
 * Sun, Sun Microsystems, the Sun logo, Java and J2EE are trademarks
 * or registered trademarks of Sun Microsystems, Inc. in the U.S. and
 * other countries.
 *
 * Copyright (c) 2005 Sun Microsystems, Inc. Tous droits reserves.
 *
 * Droits du gouvernement americain, utilisateurs gouvernementaux - logiciel
 * commercial. Les utilisateurs gouvernementaux sont soumis au contrat de
 * licence standard de Sun Microsystems, Inc., ainsi qu'aux dispositions
 * en vigueur de la FAR (Federal Acquisition Regulations) et des
 * supplements a celles-ci.  Distribue par des licences qui en
 * restreignent l'utilisation.
 *
 * Cette distribution peut comprendre des composants developpes par des
 * tierces parties. Sun, Sun Microsystems, le logo Sun, Java et J2EE
 * sont des marques de fabrique ou des marques deposees de Sun
 * Microsystems, Inc. aux Etats-Unis et dans d'autres pays.
 */


package com.sun.ebank.util;

import java.util.*;
import java.text.SimpleDateFormat;


/**
 * This class contains helper methods for dealing with
 * Date objects.
 */
public final class DateHelper {
    public static final Date getDate(int year, int month, int day, int hour,
        int minute) {
        // returns a Date with the specified time elements
        Calendar cal =
            new GregorianCalendar(year, intToCalendarMonth(month), day, hour,
                minute);

        return cal.getTime();
    }
     // getDate

    public static final Date getDate(int year, int month, int day) {
        // returns a Date with the specified time elements,
        // with the hour and minutes both set to 0 (midnight)
        Calendar cal =
            new GregorianCalendar(year, intToCalendarMonth(month), day);

        return cal.getTime();
    }
     // getDate

    static public final Date addDays(Date target, int days) {
        // returns a Date that is the sum of the target Date
        // and the specified number of days;
        // to subtract days from the target Date, the days
        // argument should be negative
        long msPerDay = 1000 * 60 * 60 * 24;
        long msTarget = target.getTime();
        long msSum = msTarget + (msPerDay * days);
        Date result = new Date();
        result.setTime(msSum);

        return result;
    }
     // addDays

    static public int dayDiff(Date first, Date second) {
        // returns the difference, in days, between the first
        // and second Date arguments
        long msPerDay = 1000 * 60 * 60 * 24;
        long diff =
            (first.getTime() / msPerDay) - (second.getTime() / msPerDay);
        Long convertLong = new Long(diff);

        return convertLong.intValue();
    }
     // dayDiff

    static public int getYear(Date date) {
        Calendar cal = new GregorianCalendar();
        cal.setTime(date);

        return cal.get(Calendar.YEAR);
    }
     // getYear 

    static public int getMonth(Date date) {
        Calendar cal = new GregorianCalendar();
        cal.setTime(date);

        int calendarMonth = cal.get(Calendar.MONTH);

        return calendarMonthToInt(calendarMonth);
    }
     // getMonth

    static public int getDay(Date date) {
        Calendar cal = new GregorianCalendar();
        cal.setTime(date);

        return cal.get(Calendar.DAY_OF_MONTH);
    }
     // getDay

    static public int getHour(Date date) {
        Calendar cal = new GregorianCalendar();
        cal.setTime(date);

        return cal.get(Calendar.HOUR_OF_DAY);
    }
     // geHour

    static public int getMinute(Date date) {
        Calendar cal = new GregorianCalendar();
        cal.setTime(date);

        return cal.get(Calendar.MINUTE);
    }
     // geMinute

    private static int calendarMonthToInt(int calendarMonth) {
        if (calendarMonth == Calendar.JANUARY) {
            return 1;
        } else if (calendarMonth == Calendar.FEBRUARY) {
            return 2;
        } else if (calendarMonth == Calendar.MARCH) {
            return 3;
        } else if (calendarMonth == Calendar.APRIL) {
            return 4;
        } else if (calendarMonth == Calendar.MAY) {
            return 5;
        } else if (calendarMonth == Calendar.JUNE) {
            return 6;
        } else if (calendarMonth == Calendar.JULY) {
            return 7;
        } else if (calendarMonth == Calendar.AUGUST) {
            return 8;
        } else if (calendarMonth == Calendar.SEPTEMBER) {
            return 9;
        } else if (calendarMonth == Calendar.OCTOBER) {
            return 10;
        } else if (calendarMonth == Calendar.NOVEMBER) {
            return 11;
        } else if (calendarMonth == Calendar.DECEMBER) {
            return 12;
        } else {
            return 1;
        }
    }
     // calendarMonthToInt

    public static String format(Date date, String pattern) {
        // returns a String representation of the date argument,
        // formatted according to the pattern argument, which
        // has the same syntax as the argument of the SimpleDateFormat
        // class1E
        SimpleDateFormat formatter = new SimpleDateFormat(pattern);

        return formatter.format(date);
    }
     // format

    private static int intToCalendarMonth(int month) {
        if (month == 1) {
            return Calendar.JANUARY;
        } else if (month == 2) {
            return Calendar.FEBRUARY;
        } else if (month == 3) {
            return Calendar.MARCH;
        } else if (month == 4) {
            return Calendar.APRIL;
        } else if (month == 5) {
            return Calendar.MAY;
        } else if (month == 6) {
            return Calendar.JUNE;
        } else if (month == 7) {
            return Calendar.JULY;
        } else if (month == 8) {
            return Calendar.AUGUST;
        } else if (month == 9) {
            return Calendar.SEPTEMBER;
        } else if (month == 10) {
            return Calendar.OCTOBER;
        } else if (month == 11) {
            return Calendar.NOVEMBER;
        } else if (month == 12) {
            return Calendar.DECEMBER;
        } else {
            return Calendar.JANUARY;
        }
    }
     // intToCalendarMonth
}
 // class