时间处理

这是网上找的一个时间处理的类，没有看到jakata里面有这一方面的东东，因此复制了下来

import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;


public class DateUtil {

	public String getPrintDate() {
		String printDate = "";
		Calendar calendar = new GregorianCalendar();
		calendar.setTime(new Date());
		printDate += calendar.get(Calendar.YEAR) + "年";
		printDate += (calendar.get(Calendar.MONTH) + 1) + "月";
		printDate += calendar.get(Calendar.DATE) + "日";
		return printDate;
	}

	/**
	 * 将指定的日期字符串转化为日期对象
	 * 
	 * @param dateStr
	 *            日期字符串
	 * @return java.util.Date
	 */
	public static Date getDate(String dateStr, String format) throws Exception {

		if (dateStr == null || format == null) {
			throw new Exception("数据类型异常" + dateStr + "|" + format);
		}

		SimpleDateFormat df = new SimpleDateFormat(format);

		try {
			Date date = df.parse(dateStr);
			return date;
		} catch (Exception ex) {
			return null;
		}
	}

	/**
	 * 将指定日期转换为 Timestamp
	 * 
	 * @param date
	 *            指定日期格式为 "20030908"
	 * @return Timestamp
	 * @throws Exception
	 */
	public static Timestamp getTimestamp(String dateStr) throws Exception {
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd 00:00:00.000");
		return Timestamp.valueOf(sdf.format(getDate(dateStr, "yyyyMMdd")));
	}

	/**
	 * 从指定Timestamp中得到相应的日期
	 * 
	 * @param datetime
	 *            指定的Timestamp
	 * @return 日期 "2003-09-08"
	 */
	public String getDateFromDateTime(Timestamp datetime) {
		SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
		return sdf.format(datetime).toString();
	}

	/**
	 * 得到当前时间的时间戳
	 * 
	 * @return 当前时间戳
	 */
	public Timestamp getNowTimestamp() {
		long curTime = System.currentTimeMillis();
		return new Timestamp(curTime);
	}
	
	public static void main(String[] args) throws Exception {
		String dateStr="20080921";
		String format="yyyyMMdd";		
		DateUtil dateUtil=new DateUtil();		
		Date date=dateUtil.getDate(dateStr, format);		
		System.out.println(date);
		System.out.println(dateUtil.getNowTimestamp());
		System.out.println(dateUtil.getTimestamp(dateStr));
		System.out.println(dateUtil.getPrintDate());

	}

}