Null-safe valueOf method

Question

I need to convert several String values to Integer,Boolean, etc., however since the input values may be null I can't use the Integer.valueOf() method for example. If the input is null I need the output object to be null as well, so I can't use apache commons NumberUtils.toInt(). Is there an existing implementation or a better solution than just writing a utility method for each type(Integer, Boolean etc.)?

Edit: adding code sample

String maxAgeStr = settings.get("maxAge"); //settings is a map, which may or //may not contain maxAge constraints.setMaxAge(Integer.valueOf(maxAgeStr)); // need null safety here String enableActionStr = settings.get("enableAction"); constraints.setEnableAction(Boolean.valueOf(enableActionStr)); // need null safety here

Answer 1

Use commons-lang NumberUtils.createInteger() method:

NumberUtils.createInteger(null); // null
NumberUtils.createInteger("5"); // 5

Answer 2

Touches Java 8:

Optional<String> maxAgeStr = Optional.ofNullable(settings.get("maxAge"));
maxAgeStr.ifPresent((str) -> { constraints.setMaxAge(Integer.valueOf(str)); });

Optional<String> enableActionStr = Optional.ofNullable(settings.get("enableAction"));
constraints.setEnableAction(Boolean.valueOf(enableActionStr.orElse(false))); 

Optional<String> enableActionStr = Optional.ofNullable(settings.get("enableAction"));
constraints.setEnableAction(Boolean.valueOf(enableActionStr.orElseGet(() -> i%2 == 0)));