JAVA中日期 yyyy-MM-dd HH:mm:ss和yyyy-MM-dd hh:mm:ss的区别

package time;

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

/**
 * Created by sheting on 10/20/2017
 */
public class Test {
    public static void main(String[] args) {
        // hh 是12小时制
        DateFormat dateTimeformat = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
        String strBeginDate = dateTimeformat.format(new Date());
        System.out.println(strBeginDate);  //2017-10-20 11:59:23

       // HH 是24小时制
        DateFormat dateTimeformat2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String strBeginDate2 = dateTimeformat2.format(new Date());
        System.out.println(strBeginDate2);  //2017-10-20 11:59:23
    }
}