package com.cloud.util;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class DateUtil {
	/* 私有構造方法，工具類不需要例項化 */
	private DateUtil(){}
	/* 判斷是否是時間型別 */
	public static boolean idDate(String dateStr){
		try {
			DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
			df.parse(dateStr);
			return true;
		} catch (ParseException e) {
			return false;
		}
	}
	/* 格式化日期 */
	public static Date parseDate(String dateStr, String format) {
		Date date = null;
		try {
			java.text.DateFormat df = new java.text.SimpleDateFormat(format);
			String dt = (dateStr).replaceAll("-", "/");
			if ((!dt.equals("")) && (dt.length() < format.length())) {
				dt += format.substring(dt.length()).replaceAll("[YyMmDdHhSs]","0");
			}
			date = (Date) df.parse(dt);
		} catch (Exception e) {
		}
		return date;
	}
	/* 格式化日期：yyyy/MM/dd 形式 */
	public static Date parseDate(String dateStr){
		return parseDate(dateStr.replace("-", "/"),"yyyy/MM/dd");
	}
	/* 格式化日期：java.sql.Date 型別轉換為 java.util.Date型別 */
	public static Date parseDate(java.sql.Date date){
		return date;
	}
	/* 格式化日期：  java.util.Date型別轉換java.sql.Date型別 */
	public static java.sql.Date parseSqlDate(Date date){
		if(date!=null)
			return new java.sql.Date(date.getTime());
		else
			return null;
	}
	/* 根據String日期，並按照格式，返回SQL日期 */
	public static java.sql.Date parseSqlDate(String dateStr,String format){
		Date date = parseDate(dateStr, format);
		return parseSqlDate(date);
	}
	/* 根據String日期，返回SQL日期  */
	public static java.sql.Date parseSqlDate(String dateStr){
		return parseSqlDate(dateStr, "yyyy/MM/dd");
	}
	/* 根據String日期，並根據一定的格式轉換成java.sql.Timestamp的日期  */
	public static java.sql.Timestamp parseTimestamp(String dateStr,String format){
		Date date = parseDate(dateStr, format);
		if(date!=null){
			long time = date.getTime();
			return new java.sql.Timestamp(time);
		} else
			return null;
	}
	/* 根據dateStr 字串日期  返回yyyy/MM/dd  HH:mm:ss 格式的java.sql.Timestamp日期  */
	public static java.sql.Timestamp parseTimestamp(String dateStr){
		return parseTimestamp(dateStr.replace("-", "/"), "yyyy/MM/dd HH:mm:ss");
	}
	/* 格式化date型別為String型別日期格式  */
	public static String format(Date date,String format){
		String result = "";
		try{
			if(date!=null){
				DateFormat df = new SimpleDateFormat(format);
				result = df.format(date);
			}
		} catch(Exception e){}
		return result;
	}
	/* 格式化date型別  */
	public static String format(Date date){
		return format(date,"yyyy/MM/dd");
	}
	/* 獲取日期的年份 */
	public static int getYear(Date date){
		Calendar c = Calendar.getInstance();
		c.setTime(date);
		return c.get(Calendar.YEAR);
	}
	/* 獲取日期的月份 */
	public static int getMonth(Date date){
		Calendar c = Calendar.getInstance();
		c.setTime(date);
		return c.get(Calendar.MONTH)+1;
	}
	/* 獲取日期的天份 */
	public static int getDay(Date date){
		Calendar c = Calendar.getInstance();
		c.setTime(date);
		return c.get(Calendar.DAY_OF_MONTH);
	}
	/* 獲取小時 */
	public static int getHour(Date date){
		Calendar c = Calendar.getInstance();
		c.setTime(date);
		return c.get(Calendar.HOUR_OF_DAY);
	}
	/* 獲取分鐘 */
	public static int getMinute(Date date){
		Calendar c = Calendar.getInstance();
		c.setTime(date);
		return c.get(Calendar.MINUTE);
	}
	/* 獲取秒鐘 */
	public static int getSecond(Date date){
		Calendar c = Calendar.getInstance();
		c.setTime(date);
		return c.get(Calendar.SECOND);
	}
	/* 獲取毫秒 */
	public static long getMillis(Date date){
		Calendar c = Calendar.getInstance();
		c.setTime(date);
		return c.getTimeInMillis();
	}
	/* 返回字元型別時間 */
	public static String getTime(Date date){
		return format(date, "HH:mm:ss");
	}
	/* 返回字元型別的日期和時間 */
	public static String getDateTime(Date date){
		return format(date, "yyyy/MM/dd HH:mm:ss");
	}
	/* 返回日期相加後的日期 */
	public static Date addDate(Date date,int day){
		Calendar c = Calendar.getInstance();
		c.setTimeInMillis(getMillis(date)+((long) day) * 24 * 3600 * 1000);
		return c.getTime();
	}
	/* 兩個日期相減 */
	public static int diffDate(Date date,Date date1){
		return (int)((getMinute(date)-getMillis(date1))/(24 * 3600 * 1000));
	}
}
 

簡單測試

package com.cloud.test;

import java.util.Date;
import com.cloud.util.DateUtil;
public class TestDateUtil {
	public static void main(String[] args) {

		boolean flag = DateUtil.idDate("2014-05-17");
		System.out.println(flag);
		Date date = DateUtil.parseDate("2016/11/12");
		System.out.println(date.toString());
		String time = DateUtil.getTime(new Date());
		System.out.println(time);
	}
}