Jersey REST does not return data in the format from Accept header

Question

CustomObjectResource - rest service returning a simple POJO with text, long and local date time fields.

@Component
@Path("/resource")
public class CustomObjectResource {

    private RandomCOBuilder randomCOBuilder = new RandomCOBuilder();

    @GET
    @Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
    public Response getCustomObject(@Context HttpServletRequest httpRequest) {
        String acceptHeader = httpRequest.getHeader("Accept");//I do not use it in the code. When I debug, this param is correct.
        CustomObject customObject = randomCOBuilder.get();
        return Response
                // Set the status and Put your entity here.
                .ok(customObject)
                // Add the Content-Type header to tell Jersey which format it should marshall the entity into.
                .build();
    }
}

And this is my Postman. Part -1 accept=json Status code is 200, the JSON parsing fails. Actually, the object returned is in XML. When I choose to display the result in XML,

<customObject>
    <id>5</id>
    <text>CustomObject_5</text>
    <timestamp>2017-08-07 17:17:40</timestamp>
</customObject>

Now, I use Accept:application/xml

Part-2 accept xml

It does not return anything: 404.

I use SpringBoot with Jackson.

This is my gradle.build

group 'com.ca.training.rest'
version '1.0-SNAPSHOT'

apply plugin: 'java'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    compile "org.springframework.boot:spring-boot-starter-jetty:1.5.3.RELEASE"
    compile "org.springframework.boot:spring-boot-starter-web:1.5.3.RELEASE"

    compile "com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.8.8"
    compile "com.fasterxml.jackson.dataformat:jackson-dataformat-xml:2.8.8"

    compile 'javax.ws.rs:javax.ws.rs-api:2.0.1'
    compile "org.springframework.boot:spring-boot-starter-jersey:1.5.3.RELEASE"

    testCompile 'junit:junit:4.12'
}

CustomObject

@XmlRootElement(name = "customObject")
@JsonRootName(value = "customObject")
public class CustomObject {

    private Long id;
    private String text;

    @JsonFormat(pattern = DATE_FORMAT)
    @XmlJavaTypeAdapter(DateTimeAdapter.class)
    private LocalDateTime timestamp;

}

Update

I was debugging. In my code everything works well... But when I debugged further:

com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException: 1 counts of IllegalAnnotationExceptions
Class has two properties of the same name "timestamp"
    this problem is related to the following location:
        at public java.time.LocalDateTime com.ca.training.rest.example.core.entity.CustomObject.getTimestamp()
        at com.ca.training.rest.example.core.entity.CustomObject
    this problem is related to the following location:
        at private java.time.LocalDateTime com.ca.training.rest.example.core.entity.CustomObject.timestamp
        at com.ca.training.rest.example.core.entity.CustomObject

Answer 1

This is the solution.

1) @XmlAccessorType(XmlAccessType.FIELD) to get rid of the error. Otherwise it picks up properties from fields and getters.

@XmlRootElement(name = "customObject")
@JsonRootName(value = "customObject")
@XmlAccessorType(XmlAccessType.FIELD)
public class CustomObject {

    private Long id;
    private String text;

    @JsonFormat(pattern = DATE_FORMAT)
    @XmlJavaTypeAdapter(DateTimeAdapter.class)
    private LocalDateTime timestamp;

    //Getters and setters
}

2) In JerseyConfig add Jackson config

@Component
public class JerseyConfig extends ResourceConfig {

    public JerseyConfig() {
        registerEndpoints();
    }

    private void registerEndpoints() {
         register(CustomObjectResource.class);
         register(JacksonConfig.class);//I need this
    }
}

3) And Jackson config

@Provider
public class JacksonConfig implements ContextResolver<ObjectMapper> {

    private ObjectMapper objectMapper = objectMapper();

    private ObjectMapper objectMapper() {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
        objectMapper = builder.build();
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        objectMapper.configure(SerializationFeature.WRAP_ROOT_VALUE, true);
        objectMapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true);
        return objectMapper;
    }

    @Override
    public ObjectMapper getContext(Class<?> type) {
        return objectMapper;
    }
}

Now it works and returns the object in both XML and JSON.

Accept:application/xml

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<customObject>
    <id>2</id>
    <text>CustomObject_2</text>
    <timestamp>2017-08-08 11:49:47</timestamp>
</customObject>

Accept:application/json

{
    "customObject": {
        "id": 3,
        "text": "CustomObject_3",
        "timestamp": "2017-08-08 11:50:25"
    }
}