import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class DateTest {
    
    public static void main(String[] args) throws ParseException {
        Date date = new Date();
        /*
         * 把java.util.Date转换为指定格式String
         */
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String dateStr = sdf.format(date);
        System.out.println(dateStr);//
        System.out.println(sdf1.format(date));
        //通过String.format把日期转换为String
        System.out.println(String.format("%tF %<tT", date));
        
        /*
         * 把String转换为Date
         */
        Date date1 = sdf.parse(dateStr);
        System.out.println(date1);
    }
}