一.案例

package org.hyena.dorm.publics.util;

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

/**
 * @author 作者 hq.zheng:
 * @version 建立時間：2018-11-8 上午8:22:59
 * 時間工具類
 */
public class DormDateTimeUtil {
	 /**
     * 判斷當前時間是否在[startTime, endTime]區間，注意時間格式要一致
     * 
     * @param nowTime 當前時間
     * @param startTime 開始時間
     * @param endTime 結束時間
     * @return
     * @author hq.zheng
     */
	public static boolean isEffectiveDate(Date nowTime, Date startTime, Date endTime) {
        if (nowTime.getTime() == startTime.getTime()
                || nowTime.getTime() == endTime.getTime()) {
            return true;
        }

        Calendar date = Calendar.getInstance();
        date.setTime(nowTime);

        Calendar begin = Calendar.getInstance();
        begin.setTime(startTime);

        Calendar end = Calendar.getInstance();
        end.setTime(endTime);

        if (date.after(begin) && date.before(end)) {
            return true;
        } else {
            return false;
        }
    }
	 /**
     * 獲取當前月的第一天
     * 
     * @return
     * @author hq.zheng
     */
	public static Date getThisMonthFirstDay(){
		Calendar cale = Calendar.getInstance();
		cale.add(Calendar.MONTH, 0);
		cale.set(Calendar.DAY_OF_MONTH, 1);
		return cale.getTime();
	}
	 /**
     * 獲取當前月的最後一天
     * 
     * @return
     * @author hq.zheng
     */
	public static Date getThisMonthLastday(){
		Calendar cale = Calendar.getInstance();
		cale.add(Calendar.MONTH, 1);
        cale.set(Calendar.DAY_OF_MONTH, 0);
        return cale.getTime();
	}
	/**
     * 獲取上月的第一天
     * 
     * @return
     * @author hq.zheng
     */
	public static Date getPrecedMonthFirstDay(){
		Calendar cale = Calendar.getInstance();
		cale = Calendar.getInstance();
	    cale.add(Calendar.MONTH, -1);
	    cale.set(Calendar.DAY_OF_MONTH, 1);
	    return cale.getTime();
	}
	/**
     * 獲取上月的最後一天
     * 
     * @return
     * @author hq.zheng
     */
	public static Date getPrecedMonthLastday(){
		Calendar cale = Calendar.getInstance();
		cale = Calendar.getInstance();
		cale.add(Calendar.MONTH, 0);
	    cale.set(Calendar.DAY_OF_MONTH, 0);
	    return cale.getTime();
	}
	/**
     * 將字串時間轉成日期時間
     * 
     * @param nowDate 當前時間
     * @param format 轉的格式，如[yyyy-MM-dd],[yyyy年MM月dd日 HH時mm分ss秒]
     * @return
     * @author hq.zheng
     */
	public static Date formatStringToDate(String nowDate,String format){
		SimpleDateFormat sdf = new SimpleDateFormat(format);
		Date date=null;
		try {
			date=sdf.parse(nowDate);
		} catch (Exception e) {
			e.printStackTrace();
			return date;
		}
		return date;
	}
}