java常用日期操作

/**
 * 根据开始日期 ，需要的工作日天数 ，计算工作截止日期，并返回截止日期
 * @param startDate 开始日期
 * @param workDay 工作日天数(周一到周五)
 * @return Date类型
 * @createTime 2014-2-14
 * @author Sunqinbo
 */
public static Date getWorkDay(Date startDate, int workDay) {
    Calendar c1 = Calendar.getInstance();
    c1.setTime(startDate);
    for (int i = 0; i < workDay; i++) {
        c1.set(Calendar.DATE, c1.get(Calendar.DATE) + 1);
        if (Calendar.SATURDAY == c1.get(Calendar.SATURDAY) || Calendar.SUNDAY == c1.get(Calendar.SUNDAY)) {
            workDay = workDay + 1;
            c1.set(Calendar.DATE, c1.get(Calendar.DATE) + 1);
            continue;
        }
    }
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    System.out.println(df.format(c1.getTime()) + " " + getWeekOfDate(c1.getTime()));
    return c1.getTime();
}
 
/**
 * 根据日期，获取星期几
 * @param dt
 * @return String类型
 * @createTime 2014-2-14
 * @author Sunqinbo
 */
public static String getWeekOfDate(Date dt) {
    String[] weekDays = { "星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六" };
    Calendar cal = Calendar.getInstance();
    cal.setTime(dt);
    int w = cal.get(Calendar.DAY_OF_WEEK) - 1;
    if (w < 0) w = 0;
    return weekDays[w];
}
 
public static void main(String[] args) {
    for (int i = 0; i < 10; i++) {
        System.out.print("工作日：" + i + " ");
        getWorkDay(new Date(), i);
    }
}