import java.util.Calendar;
import java.util.Date;
/**
 * 功能：計算時間
 * 上月開始、上月結束、本月開始、本月結束、上周開始、上周結束、本周開始、本周結束、昨天開始、昨天結束、今天開始、今天結束
 * @see
 * @version 2007-06-07
 *
 */

public class StartAndEndOfDate {
    public static enum DateTag {LAST_MONTH_START,LAST_MONTH_END,THIS_MONTH_START,THIS_MONTH_END,LAST_WEEK_START,LAST_WEEK_END,
        THIS_WEEK_START,THIS_WEEK_END,YESTERDAY_START,YESTERDAY_END,TODAY_START,TODAY_END,NOW};
    
    /**
     * 功能：計算時間
     * 上月開始、上月結束、本月開始、本月結束、上周開始、上周結束、本周開始、本周結束、昨天開始、昨天結束、今天開始、今天結束
     * 格式：2007-06-01 00:00:00  2007-06-30 23:59:59
     * 本月結束、本周結束、今天結束 都指的是當前日期時間
     * 一周按照：星期一至星期天來計算
     * @param tag
     * @return String
     */
    public static String getStartAndEndDate(DateTag tag){
        String resultString;
        Calendar cal = Calendar.getInstance();
        Date date = new Date();
        java.text.DateFormat formatFull = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String now = formatFull.format(date);
        java.text.DateFormat format = new java.text.SimpleDateFormat("yyyy-MM-dd");
        switch (tag){
            case LAST_MONTH_START://上月開始
                cal.add(Calendar.MONTH, -1); 
                cal.set(Calendar.DATE, 1); 
                String lastMonthStart = format.format(cal.getTime())+" 00:00:00";//上月開始（上月1號）
                cal.clear();
                resultString = lastMonthStart;
                break;
            case LAST_MONTH_END://上月結束
                cal=Calendar.getInstance();
                cal.add(Calendar.MONTH, -1); 
                cal.set(Calendar.DATE,cal.getActualMaximum(Calendar.DAY_OF_MONTH));
                String lastMonthEnd = format.format(cal.getTime())+" 23:59:59";//上月結束（上月最后一天）
                cal.clear();
                resultString = lastMonthEnd;
                break;
            case THIS_MONTH_START://本月開始
                cal=Calendar.getInstance();
                cal.add(Calendar.MONDAY,0);
                cal.set(Calendar.DAY_OF_MONTH, 1); 
                String thisMonthStart = format.format(cal.getTime())+" 00:00:00";//本月開始（本月1號）
                cal.clear();
                resultString = thisMonthStart;
                break;
            case THIS_MONTH_END://本月結束
                String thisMonthEnd = now;//本月結束（即：當前時間）
                resultString = thisMonthEnd;
                break;
            case LAST_WEEK_START://上周開始
                cal=Calendar.getInstance();
                cal.add(Calendar.WEEK_OF_YEAR, -1);
                cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
                String lastWeekStart = format.format(cal.getTime())+" 00:00:00";//上周開始（即：上周一）
                cal.clear();
                resultString = lastWeekStart;
                break;
            case LAST_WEEK_END://上周結束
                cal=Calendar.getInstance();
                cal.add(Calendar.WEEK_OF_YEAR, 0);
                cal.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
                String lastWeekEnd = format.format(cal.getTime())+" 23:59:59";//上周結束（即：上周日）
                cal.clear();
                resultString = lastWeekEnd;
                break;
            case THIS_WEEK_START://本周開始
                cal=Calendar.getInstance();
                cal.add(Calendar.WEEK_OF_YEAR, 0);
                cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
                String thisWeekStart = format.format(cal.getTime())+" 00:00:00";//本周開始（即：本周一）
                cal.clear();
                resultString = thisWeekStart;
                break;
            case THIS_WEEK_END://本周結束
                String thisWeekEnd = now;//本周結束(即：當前時間)
                resultString = thisWeekEnd;
                break;
            case YESTERDAY_START://昨天開始
                cal = Calendar.getInstance();
                cal.add(Calendar.DAY_OF_MONTH, -1);
                format = new java.text.SimpleDateFormat("yyyy-MM-dd");
                String yesterdayStart= format.format(cal.getTime());
                yesterdayStart = yesterdayStart+" 00:00:00";//昨天開始
                cal.clear();
                resultString = yesterdayStart;
                break;
            case YESTERDAY_END://昨天結束
                cal = Calendar.getInstance();
                cal.add(Calendar.DAY_OF_MONTH, -1);
                format = new java.text.SimpleDateFormat("yyyy-MM-dd");
                String yesterdayEnd= format.format(cal.getTime());
                yesterdayEnd = yesterdayEnd+" 23:59:59";//昨天結束
                cal.clear();
                resultString = yesterdayEnd;
                break;
            case TODAY_START://今天開始
                String todayStart=format.format(date)+" 00:00:00";//今天開始
                resultString = todayStart;
                break;
            case TODAY_END://今天結束
                String todayEnd = now;//今天結束（即；當前時間）
                resultString = todayEnd;
                break;
            default://沒有匹配的，返回當前時間
                resultString = now;
            
        }
        return resultString;

    }

}