Java8的flatMap如何处理有异常的函数

String personValue = Optional.ofNullable(map.get("person"))
        .flatMap((value) -> Optional.of(value.toString().trim()))
        .orElse("");

public static void main(String[] args) {
    Map<String, Object> map = new HashMap<>();
    String value = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
    System.out.println(value);
    map.put("time",value);

    String timeValue = "";
    if(map.get("time") != null){
        try {
            Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(map.get("time").toString().trim());
            timeValue = new SimpleDateFormat("yyyy年MM月dd日").format(date);
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }
    System.out.println(timeValue);

    String timeValue2 = Optional.ofNullable(map.get("time"))
            .flatMap((value2) -> {
                String ans = "";
                try {
                    Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(map.get("time").toString().trim());
                    ans = new SimpleDateFormat("yyyy年MM月dd日").format(date);
                } catch (ParseException e) {
                    e.printStackTrace();
                }
                return Optional.of(ans);
            }) .orElse("");
    System.out.println(timeValue2);
}