Spring Boot WebClient XML - spring-boot

Question

My spring boot application wants to use Webclient to make an http request (XML request body) and receives XML response. Hence I created another spring boot application with jackson-dataformat-xml and created an endpoint to receive and return XML as below.
spring-boot-version=2.2.5
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
</dependency>
#PostMapping(value = "/api",
consumes = MediaType.APPLICATION_XML_VALUE,
produces = MediaType.APPLICATION_XML_VALUE)
public ResponseEntity<MyXmlResponse> trip(#RequestBody MyXmlRequest request) throws Exception {
MyXmlResponse response = new MyXmlResponse();
response.setStatus("SUCCESS");
response.setTripID(request.getTripID());
return ResponseEntity.ok().body(response);
}
It works perfect and obviously no JaxB annotations are required as I use jackson-dataformat-xml. Also the request XML can be case-insensitive.
Now, in my first application I want to consume this API via webclient. I read that Spring webflux do not support Jackson-dataformat-xml yet. Hence I have to annotate my classes with Jaxb annotations.
spring-boot-version=2.2.5
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
webClient.post()
.uri(URI.create("url-to-api-endpoint"))
.body(Mono.just(myXmlRequest), MyXmlRequest.class)
.exchange()
.doOnSuccess(response -> {
HttpStatus statusCode = response.statusCode();
log.info("Status code of external system request {}", statusCode);
})
.doOnError(onError -> {
log.error("Error on connecting to external system {}", onError.getMessage());
})
.flatMap(response -> response.bodyToMono(MyXmlResponse.class))
.subscribe(this::handleResponse);
Above code throws an exception as follows
org.springframework.webreactive.function.UnsupportedMediaTypeException: Content type 'application/xml' not supported for bodyType=com.example.MyXmlRequest
at org.springframework.web.reactive.function.BodyInserters.unsupportedError(BodyInserters.java:391)
I fixed this problem by annotating with XmlRootElement as follows
#Getter #Setter #NoArgsConstructor #ToString
#XmlRootElement()
public class MyXmlRequest {
private String attribute1;
}
On the next attempt I got another error as follows
reactor.core.Exceptions$ErrorCallbackNotImplemented: org.springframework.web.reactive.function.UnsupportedMediaTypeException: Content type 'application/xml' not supported for bodyType=com.example.MyXmlResponse
Caused by: org.springframework.web.reactive.function.UnsupportedMediaTypeException: Content type 'application/xml' not supported for bodyType=com.example.MyXmlResponse
This could be solved by annotating MyXmlResponse with XmlRootElement as follows
#Getter #Setter #NoArgsConstructor #ToString
#XmlRootElement()
public class MyXmlResponse {
private String attr1;
private String attr2;
}
This time I get unmarshallexception as follows
reactor.core.Exceptions$ErrorCallbackNotImplemented: org.springframework.core.codec.DecodingException: Could not unmarshal XML to class com.example.MyXmlResponse; nested exception is javax.xml.bind.UnmarshalException
- with linked exception:
[com.sun.istack.internal.SAXParseException2; lineNumber: 1; columnNumber: 15; unexpected element (uri:"", local:"MyXmlResponse"). Expected elements are <{}myXmlResponse>]
Caused by: org.springframework.core.codec.DecodingException: Could not unmarshal XML to class com.example.MyXmlResponse; nested exception is javax.xml.bind.UnmarshalException
- with linked exception:
I fixed it with additional attributes passed to annotation as follows.
#XmlRootElement(name = "MyXmlResponse", namespace = "")
public class MyXmlResponse {
In future, my XML structures going to be tremendously complex. I want to know if I am doing it the right way.