java获取当月最后一天

/**
 * 当月最后一天
 * @param timeFlag 是否带时分秒， true是
 * @return
 */
public static String getLastDay(boolean timeFlag) {
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
    Calendar calendar = Calendar.getInstance();
    Date theDate = calendar.getTime();
    String s = df.format(theDate);
    StringBuffer str = new StringBuffer().append(s);
    if(timeFlag){
        str.append(" 23:59:59");
    }
    return str.toString();
}