I am new to Java SpringBoot and I am trying to inject a default value from application-dev.properties file. Basically, the idea is to set default value to RequestObject's id property, default value being injected(/fetched) from application-dev.properties.
UseCase: In case, no data or blank data is being passed in request body of API, the code should set a default value (being injected/fetched from application-dev.properties).
Controller Code
@RequestMapping(value = PATH, method = RequestMethod.POST, consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
private @ResponseBody ResponseEntity<ResponseBean<ResponseObject>> postController(
final @Valid @RequestBody RequestObject request) throws Exception {
return serviceClass.service(request);
}
I did the following in RequestObject Class code
public class RequestObject {
@Value("${package.default}")
private String default_id;
private String id = default_id;
public String getId() {
return id;
}
public void setId(String id) {
this.id = !StringUtils.isBlank(id) ? id : default_id;
}
The above code is not working. Please help or suggest a better way to achieve the requirement.
Note: If I hardcode the id value like id="abcd" while defining & in setter method, the code is working.
CodePudding user response:
why do you use @Value("${package.default}")
in request body object? it should not work because they only mapped json into pojo object. you can use and initiate default_id using @Value("${package.default}")
in your service class. after that you can set it your RequestObject
.
CodePudding user response:
You can inject stuff(default values from application properties, other beans, etc.) only in spring managed components - those are classes annotated with @Component
, @Service
etc.
RequestObject
, being a class you map request body to, is not, and should not be a component.
In order to inject default value from application.properties you need custom deserializer, which is a bean, and register this deserializer with ObjectMapper
.
@Component
public class RequestObjectDeserializer extends StdDeserializer<RequestObject> {
@Value("${your.property.here}")
private String defaultValue;
public RequestObjectDeserializer() {
super(RequestObject.class);
}
@Override
public RequestObject deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JacksonException {
//deserialize
}
}
Then register it with already existing Objectmapper
:
@Autowired
public void configObjectMapper(ObjectMapper objectMapper, RequestObjectDeserializer deserializer) {
SimpleModule module = new SimpleModule();
module.addDeserializer(RequestObject.class, deserializer);
objectMapper.registerModule(module);
}
You can add above in any @Configuration
class.
I'd say keeping the default value as static field in RequestObject
, and having the logic in setter, is better in this case.