datestring.java

aglet的部分源码

package com.ibm.aglets.security;

/*
 * @(#)DateString.java
 * 
 * IBM Confidential-Restricted
 * 
 * OCO Source Materials
 * 
 * 03L7246 (c) Copyright IBM Corp. 1996, 1998
 * 
 * The source code for this program is not published or otherwise
 * divested of its trade secrets, irrespective of what has been
 * deposited with the U.S. Copyright Office.
 */

// - package com.ibm.awb.misc;
import java.util.Calendar;
import java.util.Date;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.text.ParseException;

/**
 * The <tt>DateString</tt> class is a converter between Date and String.
 * 
 * @version     1.00    $Date: 2001/07/28 06:33:06 $
 * @author      ONO Kouichi
 */
final public class DateString {
	/**
	 * Date string format
	 */
	final private static String FORMAT_DATE = "yyyy.MM.dd HH:mm:ss.SSS z";

	/**
	 * Gets a date format instance.
	 */
	private static SimpleDateFormat _dateFormat = null;
	Date _date = null;

	/**
	 * Constructor.
	 */
	public DateString() {
		_date = getCurrentTime();
	}
	/**
	 * Gets string from date.
	 * @param date date
	 * @return date string
	 */
	public static String date2string(Date date) {
		return date2string(date, FORMAT_DATE);
	}
	/**
	 * Gets string from date.
	 * @param date date
	 * @param format format string
	 * @return date string
	 */
	public static String date2string(Date date, String format) {
		if (date == null) {
			return null;
		} 
		SimpleDateFormat dateFormat = getDateFormatInstance(format);

		return dateFormat.format(date);
	}
	/**
	 * 
	 */
	public static Date getCurrentTime() {
		Calendar cal = Calendar.getInstance();

		if (cal == null) {
			return null;
		} 
		return cal.getTime();
	}
	private static SimpleDateFormat getDateFormatInstance() {
		if (_dateFormat == null) {
			_dateFormat = getDateFormatInstance(FORMAT_DATE);
		} 
		return _dateFormat;
	}
	private static SimpleDateFormat getDateFormatInstance(String format) {
		return new SimpleDateFormat(format);
	}
	public Date getTime() {
		return _date;
	}
	public String getTimeString() {
		return date2string(_date);
	}
	public static void main(String arg[]) {
		Date curTime = DateString.getCurrentTime();

		System.out.println("current date=" + curTime.toString());
		System.out.println(DateString.date2string(curTime));
		Date date = DateString.string2date(arg[0]);

		System.out.println(date.toString());
		DateString dtstr = new DateString();

		System.out.println(dtstr.getTime().toString());
		System.out.println(dtstr.getTimeString());
	}
	/**
	 * Gets date from string.
	 * @param date date string
	 * @return date
	 */
	public static Date string2date(String date) {
		return string2date(date, FORMAT_DATE);
	}
	/**
	 * Gets date from string.
	 * @param date date string
	 * @param format format string
	 * @return date
	 */
	public static Date string2date(String date, String format) {
		if (date == null) {
			return null;
		} 
		SimpleDateFormat dateFormat = getDateFormatInstance(format);
		Date dt = null;

		try {
			dt = dateFormat.parse(date);
		} catch (ParseException excpt) {
			return null;
		} 
		return dt;
	}
}