本轉換在專案中經常遇見，現簡要地說明：

(1) Date轉換為Datetime

Datetime在java資料庫中對應的是Timestamp，轉換如下：

		//java.util.Date轉換為Timestamp
		Date date = new Date();
		Timestamp timestamp = new Timestamp(date.getTime()); //2013-01-14 22:45:36.484

(2) String轉換為Date

		//String轉換為java.util.Date
		String str = "2013-01-14";
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		Date date = null; //初始化date
		try {
			date = sdf.parse(str); //Mon Jan 14 00:00:00 CST 2013
		} catch (ParseException e) {
			e.printStackTrace();
		}
 

(3) Date轉換為String

		//java.util.Date轉換為String
		Date date = new Date();
		DateFormat format = new SimpleDateFormat("yyyy-MM-dd");
		String str = format.format(date); //2013-01-14

(4) String轉化為java.sql.Date

轉換為java.sql.Date目的是要對資料庫進行操作

		//String轉換為java.sql.Date
		String str = "2013-01-14";
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		java.sql.Date sdate = null; //初始化
		try {
			java.util.Date udate = sdf.parse(str);
			sdate = new java.sql.Date(udate.getTime()); //2013-01-14
		} catch (ParseException e) {
			e.printStackTrace();
		}