RestTemplate does not handle null uri template parameters [SPR-7314]

[spring-projects-issues]

chris snow opened SPR-7314 and commented

I am trying to call a rest service that has an optional path parameter (areaId, below). Setting the optional path parameter to null causes a NPE (exception below). The implications of this are that I have to create a different version of the method call for each optional call parameter and use lots of conditional logic to check if parameter values are null to decide which method to use.

String FIND_AREAS_QUERY = 
    "/areas/{areaId}?countryId={countryId}&cityId={cityId}"; 

searchCriteria.setCountryID(123);
searchCriteria.setCityID(345);
searchCriteria.setAreaID(null);

areas = restTemplate.getForObject(
    restEndpointUrl + FIND_AREAS_QUERY,
    Areas.class,
    searchCriteria.getAreaID(),   /* NPE */
    searchCriteria.getCountryID(),
    searchCriteria.getCityID()
);

The exception is as follows:

java.lang.NullPointerException
	at org.springframework.web.util.UriTemplate.expand(UriTemplate.java:128)
	at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:400)
	at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:199)

The current workaround is below: This can get quite a burden for lots of optional parameters.

String FIND_AREAS_QUERY = 
    "/areas/{areaId}?countryId={countryId}&cityId={cityId}"; 

searchCriteria.setCountryID(123);
searchCriteria.setCityID(345);
searchCriteria.setAreaID(null);

if (searchCriteria.getAreaID() != null) {
   areas = restTemplate.getForObject(
       restEndpointUrl + FIND_AREAS_QUERY,
       Areas.class,
       searchCriteria.getAreaID(),
       searchCriteria.getCountryID(),
       searchCriteria.getCityID()
   );
} else {
   areas = restTemplate.getForObject(
       restEndpointUrl + FIND_AREAS_QUERY,
       Areas.class,
       searchCriteria.getCountryID(),
       searchCriteria.getCityID()
   );
}

---

Affects: 3.0.2

Referenced from: commits 3160ddf

[spring-projects-issues]

Arjen Poutsma commented

Fixed!