spring - Multiple scenarios @RequestMapping produces JSON/XML together with Accept or ResponseEntity

Question

I am working with Spring 4.0.7

About Spring MVC, for research purposes, I have the following:

@RequestMapping(value="/getjsonperson", 
                method=RequestMethod.GET, 
                produces=MediaType.APPLICATION_JSON_VALUE)
public @ResponseBody Person getJSONPerson(){
    logger.info("getJSONPerson - getjsonperson");
    return PersonFactory.createPerson();
}

@RequestMapping(value="/getperson.json", method=RequestMethod.GET)
public @ResponseBody Person getPersonJSON(){
    logger.info("getPerson - getpersonJSON");
    return PersonFactory.createPerson();
}

Each one works fine, observe both for JSON, with and without extension:

• /getjsonperson
• /getperson.json

Same for XML

@RequestMapping(value="/getxmlperson",
                method=RequestMethod.GET,
                produces=MediaType.APPLICATION_XML_VALUE
                )
public @ResponseBody Person getXMLPerson(){
    logger.info("getXMLPerson - getxmlperson");
    return PersonFactory.createPerson();
}

@RequestMapping(value="/getperson.xml", method=RequestMethod.GET)
@ResponseBody
public Person getPersonXML(){
    logger.info("getPerson - getpersonXML");
    return PersonFactory.createPerson();
}

Each one works fine, observe both for XML, with and without extension:

• /getxmlperson
• /getperson.xml

Now about Restful I have the following:

@RequestMapping(value="/person/{id}/", 
                method=RequestMethod.GET,
                produces={MediaType.APPLICATION_JSON_VALUE, 
                          MediaType.APPLICATION_XML_VALUE})
public ResponseEntity<Person> getPersonCustomizedRestrict(@PathVariable Integer id){
    Person person = personMapRepository.findPerson(id);
    return new ResponseEntity<>(person, HttpStatus.FOUND);//302     
}

Observe the MediaType, it is mixed, for JSON and XML

Through RestTemplate I can indicate the Accept value

    if(type.equals("JSON")){
        logger.info("JSON");
        headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
    }
    else if(type.equals("XML")){
        logger.info("XML");
        headers.setAccept(Arrays.asList(MediaType.APPLICATION_XML));
    }
    ….

    ResponseEntity<Person> response =
                restTemplate.exchange("http://localhost:8080/spring-utility/person/{id}/customizedrestrict",
                                      HttpMethod.GET,
                                      new HttpEntity<Person>(headers),  
                                      Person.class,
                                       id
                                     ); 

Until here, therefore I am able to use one URL/URI to get some data in either XML or JSON formats. It works fine

My problem is with Spring MVC … just consider

@RequestMapping(value="/{id}/person", 
                method=RequestMethod.GET,
                produces={MediaType.APPLICATION_JSON_VALUE,  
                          MediaType.APPLICATION_XML_VALUE})
public @ResponseBody Person getPerson(@PathVariable Integer id){
    return personMapRepository.findPerson(id);
}

I can call or activate that handler method (@RequestMapping) through:

1. jQuery working with Ajax, I am able to indicate the Accept value (JSON for example)
2. Poster, through the Headers button, I can set the Accept

Question One:

But for a common link? how I can set the Accept value? is possible?

I thought in other way to around this problem.

• http://localhost:8080/spring-utility/person/getpersonformat?format=json
• http://localhost:8080/spring-utility/person/getpersonformat?format=xml

Observe:

• ?format

Therefore

@RequestMapping(value="/getpersonformat", 
                method=RequestMethod.GET,
                produces={MediaType.APPLICATION_JSON_VALUE,  
                          MediaType.APPLICATION_XML_VALUE})
public @ResponseBody Person getPerson(@RequestParam String format){
    return personMapRepository.findPerson(id);
}

Question Two:

What code for the method shown above must be added to customize the return type format? I mean, JSON or XML, Is possible?

I thought in the following:

@RequestMapping(value="/getpersonformataltern",
        method=RequestMethod.GET
        produces={MediaType.APPLICATION_JSON_VALUE, 
                  MediaType.APPLICATION_XML_VALUE}
        )
public ResponseEntity<Person> getPersonFormat(@RequestParam String format){
    logger.info("getPersonFormat - format: {}", format);
    HttpHeaders httpHeaders = new HttpHeaders();
    if(format.equals("json")){
        logger.info("Ok JSON");
        httpHeaders.setContentType(MediaType.APPLICATION_JSON);
    }
    else{
        logger.info("Ok XML");
        httpHeaders.setContentType(MediaType.APPLICATION_XML);
    }
    return new ResponseEntity<>(PersonFactory.createPerson(), httpHeaders, HttpStatus.OK);
}

But:

If I execute the URL:

• http://localhost:8080/spring-utility/person/getpersonformataltern?format=json

I get

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<person>
    <id>1</id>
    <firstName>Manuel</firstName>
    <lastName>Jordan</lastName>
…
</person>

Yes in XML!

Note: I can confirm the Console prints Ok JSON

If I execute the URL:

• http://localhost:8080/spring-utility/person/getpersonformataltern?format=xml

I get

This XML file does not appear to have any style information associated with it. 
The document tree is shown below.

<person>
    <id>1</id>
    <firstName>Manuel</firstName>
    <lastName>Jordan</lastName> 
    …
</person>

Question Three

What code for the method shown above must be added to fix the JSON output? I don't know what is wrong or is missing..

There are three questions.

Thank You

Alpha

@Override
public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
    Map<String,MediaType> mediaTypes = new LinkedHashMap<>();
    mediaTypes.put("json", MediaType.APPLICATION_JSON);
    mediaTypes.put("xml", MediaType.APPLICATION_XML);
    configurer.mediaTypes(mediaTypes);
    configurer.defaultContentType(MediaType.TEXT_HTML);
}

Answer 1

Using Accept header is really easy to get the format json or xml from the REST service.

This is my Controller, take a look produces section.

@RequestMapping(value = "properties", produces = {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE}, method = RequestMethod.GET)
    public UIProperty getProperties() {
        return uiProperty;
    }

In order to consume the REST service we can use the code below where header can be MediaType.APPLICATION_JSON_VALUE or MediaType.APPLICATION_XML_VALUE

HttpHeaders headers = new HttpHeaders();
headers.add("Accept", header);

HttpEntity entity = new HttpEntity(headers);

RestTemplate restTemplate = new RestTemplate();
ResponseEntity<String> response = restTemplate.exchange("http://localhost:8080/properties", HttpMethod.GET, entity,String.class);
return response.getBody();

Edit 01:

In order to work with application/xml, add this dependency

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
</dependency>