DateUtil（SimpleDateFormat）

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

public class DateUtil
{
    private static SimpleDateFormat format1;
    private static SimpleDateFormat format2;
    private static SimpleDateFormat format3;
    private static SimpleDateFormat format4;

    static {
        DateUtil.format1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        DateUtil.format2 = new SimpleDateFormat("yyyy-MM-dd");
        DateUtil.format3 = new SimpleDateFormat("yyyyMMddHHmmss");
        DateUtil.format4 = new SimpleDateFormat("HH:mm:ss");
    }

    public static Date getNow() {
        return Calendar.getInstance().getTime();
    }

    public static String format_yyyy_MM_dd_HH_mm_ss(final Date date) {
        return DateUtil.format1.format(date);
    }

    public static String format_yyyy_MM_dd(final Date date) {
        return DateUtil.format2.format(date);
    }

    public static String format_yyyyMMddHHmmss(final Date date) {
        return DateUtil.format3.format(date);
    }

    public static String format_HH_mm_ss(final Date date) {
        return DateUtil.format4.format(date);
    }

    public static String format(final String pattern, final Date date) {
        return new SimpleDateFormat(pattern).format(date);
    }

    public static Date getTimeForAnyHourInToday(final int hour) {
        final Calendar c = Calendar.getInstance();
        c.set(10, hour);
        c.set(12, 0);
        c.set(13, 0);
        c.set(14, 0);
        return c.getTime();
    }
}