java日期天数修改

public Date getDate(String dates){    SimpleDateFormat sdf= new SimpleDateFormat("yyyy年-MM月-dd日");    Date date=null;    try {        date = sdf.parse(dates);    } catch (ParseException e) {        // TODO Auto-generated catch block        e.printStackTrace();    }    System.out.println(date);    return date;}protected static Date addDateOneDay(Date date){    if(null==date){        return date;    }    Calendar c=Calendar.getInstance();     //    c.setTime(date);  设置当前时间        c.add(Calendar.DATE, 1);//日期加1天        date=c.getTime();    return date;}protected static String addOneDay(String dates) throws ParseException{    DateFormat df = new SimpleDateFormat("EEE MMM dd HH:mm:ss ‘CST‘ yyyy",Locale.US);    //把字符串转换成CST日期类型    Date date = df.parse(dates);    //System.out.println(date);    DateFormat sdf = new SimpleDateFormat("yyyy年-MM月-dd日");    //把CST格式转换成普通日期格式    String addOneDay=sdf.format(date);    return addOneDay;}