计算时间

 
import java.util.Calendar;
import java.util.Date;
/**
 * 功能：计算时间
 * 上月开始、上月结束、本月开始、本月结束、上周开始、上周结束、本周开始、本周结束、昨天开始、昨天结束、今天开始、今天结束
 * @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：计算时间
     * 上月开始、上月结束、本月开始、本月结束、上周开始、上周结束、本周开始、本周结束、昨天开始、昨天结束、今天开始、今天结束
     * 格式：2007-06-01 00:00:00  2007-06-30 23:59:59
     * 本月结束、本周结束、今天结束 都指的是当前日期时间
     * 一周按照：星期一至星期天来计算
     * @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://上月开始
                cal.add(Calendar.MONTH, -1);
                cal.set(Calendar.DATE, 1);
                String lastMonthStart = format.format(cal.getTime())+" 00:00:00";//上月开始（上月1号）
                cal.clear();
                resultString = lastMonthStart;
                break;
            case LAST_MONTH_END://上月结束
                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";//上月结束（上月最后一天）
                cal.clear();
                resultString = lastMonthEnd;
                break;
            case THIS_MONTH_START://本月开始
                cal=Calendar.getInstance();
                cal.add(Calendar.MONDAY,0);
                cal.set(Calendar.DAY_OF_MONTH, 1);
                String thisMonthStart = format.format(cal.getTime())+" 00:00:00";//本月开始（本月1号）
                cal.clear();
                resultString = thisMonthStart;
                break;
            case THIS_MONTH_END://本月结束
                String thisMonthEnd = now;//本月结束（即：当前时间）
                resultString = thisMonthEnd;
                break;
            case LAST_WEEK_START://上周开始
                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";//上周开始（即：上周一）
                cal.clear();
                resultString = lastWeekStart;
                break;
            case LAST_WEEK_END://上周结束
                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";//上周结束（即：上周日）
                cal.clear();
                resultString = lastWeekEnd;
                break;
            case THIS_WEEK_START://本周开始
                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";//本周开始（即：本周一）
                cal.clear();
                resultString = thisWeekStart;
                break;
            case THIS_WEEK_END://本周结束
                String thisWeekEnd = now;//本周结束(即：当前时间)
                resultString = thisWeekEnd;
                break;
            case YESTERDAY_START://昨天开始
                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";//昨天开始
                cal.clear();
                resultString = yesterdayStart;
                break;
            case YESTERDAY_END://昨天结束
                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";//昨天结束
                cal.clear();
                resultString = yesterdayEnd;
                break;
            case TODAY_START://今天开始
                String todayStart=format.format(date)+" 00:00:00";//今天开始
                resultString = todayStart;
                break;
            case TODAY_END://今天结束
                String todayEnd = now;//今天结束（即；当前时间）
                resultString = todayEnd;
                break;
            default://没有匹配的，返回当前时间
                resultString = now;
           
        }
        return resultString;

    }

}