Java线程安全的日期格式化工具类

/**
 * 日期格式化辅助类
 * 
 * @author hkb 

 */
public final class DateUtils {
     

    /** 线程安全的日期格式对象 */
    private static final ThreadLocal DATE_FORMAT = new ThreadLocal() {

        @Override
        protected DateFormat initialValue() {
            // 完整日期
            return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        }

    };

    /** 线程安全的日期格式对象 */
    private static final ThreadLocal YMD = new ThreadLocal() {

        @Override
        protected DateFormat initialValue() {
            // 年月日
            return new SimpleDateFormat("yyyy-MM-dd");
        }

    };

    /**
     * 格式化完整日期
     * 
     * @param date
     * @return yyyy-MM-dd HH:mm:ss格式的字符串
     */
    public static String formatDate(Date date) {
        return DATE_FORMAT.get().format(date);
    }

    /**
     * 格式化年月日
     * 
     * @param date
     * @return yyyy-MM-dd格式的字符串
     */
    public static String formatYMD(Date date) {
        return YMD.get().format(date);
    }

    /**
     * 获取指定日期0点的字符串
     * 
     * @param date
     * @return 返回示例:2017-12-23 00:00:00
     */
    public static String getZeroPointStr(Date date) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 0);
        return formatDate(calendar.getTime());
    }

    /**
     * 获取指定日期末点的字符串
     * 
     * @param date
     * @return 返回示例:2017-12-23 23:59:59
     */
    public static String getLastPointStr(Date date) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.HOUR_OF_DAY, 23);
        calendar.set(Calendar.MINUTE, 59);
        calendar.set(Calendar.SECOND, 59);
        calendar.set(Calendar.MILLISECOND, 999);
        return formatDate(calendar.getTime());
    }

    /**
     * 获取指定日期的0点的毫秒数
     * 
     * @param date
     * @return
     */
    public static long getZeroPointMillisecond(Date date) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 0);
        return calendar.getTime().getTime();
    }

    /**
     * 获取指定日期的末点的毫秒数
     * 
     * @param date
     * @return
     */
    public static long getLastPointMillisecond(Date date) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.HOUR_OF_DAY, 23);
        calendar.set(Calendar.MINUTE, 59);
        calendar.set(Calendar.SECOND, 59);
        calendar.set(Calendar.MILLISECOND, 999);
        return calendar.getTime().getTime();
    }

    /**
     * 测试
     * 
     * @param args
     */
    public static void main(String[] args) {
        Date now = new Date();
        System.out.println(formatDate(now));
        System.out.println(formatYMD(now));
        System.out.println(getZeroPointStr(now));
        System.out.println(getLastPointStr(now));
        System.out.println(getZeroPointMillisecond(now));
        System.out.println(getLastPointMillisecond(now));
    }

}