Spring MVC, REST, JSON, and DispatcherServlet and @RequestMapping

Question

I cannot seem to get a simple REST client integration test going. I am using Spring 3.1 MVC with a JavaConfig setup. I use Maven, and I can build, run and deploy my current webapp with no problems.

First, here's some code and config

My controller

@Controller
@RequestMapping("/rest")
public class StubRestController {

@Inject
private TestData testData;

@RequestMapping(value=Endpoints.GET_RESOURCES, method=RequestMethod.GET, produces="application/json")
@ResponseStatus(HttpStatus.OK)
public @ResponseBody JSONObject getResources(@RequestParam(value="q") String query, @RequestParam int indexFrom, @RequestParam int indexTo) throws JSONException {
    return makeRequest(query, indexFrom, indexTo, testData.getResources());
}

@RequestMapping(value=Endpoints.GET_LOCATIONS, method=RequestMethod.GET, produces="application/json")
@ResponseStatus(HttpStatus.OK)
public @ResponseBody JSONObject getLocations(@RequestParam(value="q") String query, @RequestParam int indexFrom, @RequestParam int indexTo) throws JSONException {
    return makeRequest(query, indexFrom, indexTo, testData.getLocations());
}

private JSONObject makeRequest(String query, int indexFrom, int indexTo, String[] data) throws JSONException {
    int count = 0;
    final JSONArray resources = new JSONArray();
    for (final String resourceName: data) {
        final String lowerColor = resourceName.toLowerCase();
        final int has = lowerColor.indexOf(query.toLowerCase());

        if (!query.isEmpty() && (query.equals("*") || has >= 0)) {
            final JSONObject resource = new JSONObject();
            resource.put("DisplayName", resourceName);
            resource.put("Value", resourceName);   // shouldn't this be a unique id?  e.g., resourceid
            resources.put(resource);
            count++;
        }
    }

    final JSONArray partial = new JSONArray();
    if (resources.length() > 0) {
        final int end = count - 1 > indexTo ? indexTo : count - 1;
        for (int i = indexFrom; i <= end; i++) {
            partial.put(resources.get(i));
        }
    }

    final JSONObject result = new JSONObject();
    result.put("TotalSize", count);
    result.put("Options", partial);
    return result;
}

@ExceptionHandler(JSONException.class)
@ResponseStatus(value = HttpStatus.NOT_FOUND, reason="No data found matching criteria")
public void notFound() { }
}

My test

@ContextConfiguration(classes={ RestClientContext.class }, loader=AnnotationConfigContextLoader.class)
@RunWith(SpringJUnit4ClassRunner.class)
public class StubRestClientITCase {

private static final String SCHEME = "http";
private static final String HOST = "localhost";
private static final int PORT = 8081;

// requests must match  in order to be handled by DispatcherServlet
private static final String ENDPOINT_PREFIX = "spp-emkt-mui-experimental/EMKT/services/rest";

private static final String QUERY_KEY = "q";
private static final String INDEX_FROM_KEY = "indexFrom";
private static final String INDEX_TO_KEY = "indexTo";
private static final String TOTAL_SIZE_KEY = "TotalSize";

private Logger log = LoggerFactory.getLogger(StubRestClientITCase.class);

@Inject
RestTemplate restTemplate;

@Test
public void testGetResources() {

    // Case 1:  Discover all resources using * (asterisk), first 25
    final URI uri = buildUri("*", 0, 24, Endpoints.GET_RESOURCES);
    final HttpEntity response = obtainResponse(uri);

    try {
        Assert.assertTrue(response.hasBody());
        Assert.assertEquals(25, Integer.parseInt(response.getBody().getString(TOTAL_SIZE_KEY)));
    } catch (final JSONException je) {
        fail("Could not obtain "" + TOTAL_SIZE_KEY + "" from JSON payload for getResources().
" + je.getMessage());
    }

}

private URI buildUri(String query, int indexFrom, int indexTo, String endPointUrl) {
    final UriComponents uriComponents =
            UriComponentsBuilder.newInstance()
            .scheme(SCHEME).host(HOST).port(PORT).path(ENDPOINT_PREFIX + endPointUrl)
            .queryParam(QUERY_KEY, query)
            .queryParam(INDEX_FROM_KEY, indexFrom)
            .queryParam(INDEX_TO_KEY, indexTo)
            .build()
            .encode();

    final URI uri = uriComponents.toUri();
    return uri;
}

private HttpEntity obtainResponse(URI uri) {
    final HttpHeaders requestHeaders = new HttpHeaders();
    requestHeaders.setAccept(Arrays.asList(new MediaType[] {MediaType.APPLICATION_JSON}));
    requestHeaders.setAcceptCharset(Arrays.asList(new Charset[] {Charset.forName("UTF-8")}));
    final HttpEntity requestEntity = new HttpEntity(requestHeaders);
    final HttpEntity response = restTemplate.exchange(uri, HttpMethod.GET, requestEntity, JSONObject.class);
    return response;
}
}

My web.xml





    contextClass
    
        org.springframework.web.context.support.AnnotationConfigWebApplicationContext
    



    contextConfigLocation
    com.spp.mui.gwt.server.config.WebAppContextExperimental



    org.springframework.web.context.ContextLoaderListener



    
        org.springframework.web.context.request.RequestContextListener
    



    characterEncodingFilter
    org.springframework.web.filter.CharacterEncodingFilter
    
        encoding
        UTF-8
    
    
        forceEncoding
        true
    



    characterEncodingFilter
    /*



    gwt
    org.springframework.web.servlet.DispatcherServlet
    
        contextClass
        
            org.springframework.web.context.support.AnnotationConfigWebApplicationContext
        
    
    1


    gwt
    /EMKT/service/*



    index.jsp



    0

I can see my Controller methods mapped on server startup...

17:48:58,651 INFO  [RequestMappingHandlerMapping] Mapped "{[/rest/resources],methods=[GET],params=[],headers=[],consumes=[],produces=[application/json],custom=[]}"
17:48:58,651 INFO  [RequestMappingHandlerMapping] Mapped "{[/rest/locations],methods=[GET],params=[],headers=[],consumes=[],produces=[application/json],custom=[]}"

When the test runs, I get...

17:49:00,617 DEBUG [AutowiredAnnotationBeanPostProcessor] Autowiring by type from bean name 'com.spp.mui.gwt.server.controller.stub.StubRestClientITCase' to bean named 'restTemplate'
17:49:00,648 DEBUG [RestTemplate] Created GET request for "http://localhost:8080/EMKT/services/rest/resources?q=*&indexFrom=0&indexTo=24"
17:49:00,680 DEBUG [RestTemplate] Setting request Accept header to [application/json]
17:49:00,742 WARN  [RestTemplate] GET request for "http://localhost:8080/EMKT/services/rest/resources?q=*&indexFrom=0&indexTo=24" resulted in 404 (Not Found); invoking error handler

Finally...

Tests in error:
  testGetResources(com.spp.mui.gwt.server.controller.stub.StubRestClientITCase): 404 Not Found

What could be the matter? Thinking it has something to do with url-pattern in servlet-mapping. I have tried to follow Spring docs on setup but have been unsuccessful. Note: I am inflexible on that though as I have a GWT-SL setup to map RPC service interfaces.

UPDATE #1

If I try using

curl --verbose -H "Accept: application/json" "localhost:8081/spp-emkt-mui-experimental/EMKT/service/rest/resources?q=*&indexFrom=0&indexTo=24"

against a Tomcat 6 deployment (using cargo plugin), I get a different result:

* About to connect() to localhost port 8081 (#0)
*   Trying 127.0.0.1... connected
* Connected to localhost (127.0.0.1) port 8081 (#0)
> GET /spp-emkt-mui-experimental/EMKT/service/rest/resources?q=*&indexFrom=0&indexTo=24 HTTP/1.1
> User-Agent: curl/7.21.1 (i686-pc-mingw32) libcurl/7.21.1 OpenSSL/0.9.8r zlib/1.2.3
> Host: localhost:8081
> Accept: */*
>
< HTTP/1.1 406 Not Acceptable
< Server: Apache-Coyote/1.1
< Content-Type: text/html;charset=utf-8
< Content-Length: 1070
< Date: Tue, 28 Feb 2012 05:00:26 GMT

Which seems to indicate I'm not sending appropriate header info in my request. Hmmmmmm.

UPDATE #2

The test as written returns a 404. And the curl a 406.

I've scoured so many seemingly related posts and tried so many things that I'm wondering if Spring MVC, GWT-RPC and GWT-SL are able to be combined in the same container. Considering a move to RestyGWT with server-side being Spring MVC. Comments?

Chris Phillipson · Accepted Answer

This was definitely a learning exercise on my part. I had to clear a number of hurdles with respect to configuration so that GWT RPC and Spring MVC play nicely together.

I now have a working test. The "faux pas" on my part was trying to return an @ResponseBody annotated JSONObject. Don't do this! I crafted a custom DTO and annotated with Jackson annotations like @JsonProperty, @JsonSerialize and @JsonDeserialize to get the I/O the way I wanted it.

I am presenting my working test and configuration updates below in case anyone is interested...

TEST

@ContextConfiguration(classes={ RestClientContext.class }, loader=AnnotationConfigContextLoader.class)
@RunWith(SpringJUnit4ClassRunner.class)
public class SuggestionsClientITCase {

private static final String SCHEME = "http";
private static final String HOST = "localhost";
private static final int PORT = 8080;

private static final String QUERY_KEY = "q";
private static final String INDEX_FROM_KEY = "indexFrom";
private static final String INDEX_TO_KEY = "indexTo";;

private Logger log = LoggerFactory.getLogger(SuggestionsClientITCase.class);

@Inject
RestTemplate restTemplate;

@Test
public void testGetResources() {

    // Case 1:  Discover all resources using * (asterisk), first 25
    // -- the total # of resources in TestData is 250
    // -- the total # of options returned should be constrained by indexTo - indexFrom = 25
    happyPathAssertions(Endpoints.GET_RESOURCES, "*", 0, 24, 250, 25);

}

@Test
public void testGetLocations() {

    // Case 1:  Discover all resources using * (asterisk), first 25
    // -- the total # of locations in TestData is 4316
    // -- the total # of options returned should be constrained by indexTo - indexFrom = 25
    happyPathAssertions(Endpoints.GET_LOCATIONS, "*", 0, 24, 4316, 25);

}

private void happyPathAssertions(String endpointUrl, String query, int indexFrom, int indexTo, int expectedTotal, int expectedOptionsPerPage) {
    final URI uri = buildUri(query, indexFrom, indexTo, endpointUrl);
    final HttpEntity response = obtainResponse(uri);
    Assert.assertTrue(response.hasBody());
    Assert.assertEquals(expectedTotal, response.getBody().getTotalSize());
    Assert.assertEquals(expectedOptionsPerPage, response.getBody().getOptions().size());
}

private URI buildUri(String query, int indexFrom, int indexTo, String endPointUrl) {
    final UriComponents uriComponents =
            UriComponentsBuilder.newInstance()
            .scheme(SCHEME).host(HOST).port(PORT).path(Endpoints.REST_PREFIX + endPointUrl)
            .queryParam(QUERY_KEY, query)
            .queryParam(INDEX_FROM_KEY, indexFrom)
            .queryParam(INDEX_TO_KEY, indexTo)
            .build()
            .encode();

    final URI uri = uriComponents.toUri();
    return uri;
}

private HttpEntity obtainResponse(URI uri) {
    final HttpHeaders requestHeaders = new HttpHeaders();
    requestHeaders.setAccept(Arrays.asList(new MediaType[] {MediaType.APPLICATION_JSON}));
    requestHeaders.setAcceptCharset(Arrays.asList(new Charset[] {Charset.forName("UTF-8")}));
    final HttpEntity requestEntity = new HttpEntity(requestHeaders);
    final HttpEntity response = restTemplate.exchange(uri, HttpMethod.GET, requestEntity, SuggestionsPayload.class);
    return response;
}

}

CONTROLLER

@Controller
@RequestMapping("/" + Endpoints.REST_PREFIX)
public class StubSuggestionsController {

@Inject
private TestData testData;

@RequestMapping(value=Endpoints.GET_RESOURCES, method=RequestMethod.GET, produces = {MediaType.APPLICATION_JSON_VALUE})
@ResponseStatus(HttpStatus.OK)
public @ResponseBody SuggestionsPayload getResources(@RequestParam(value="q") String query, @RequestParam int indexFrom, @RequestParam int indexTo) {
    return makeRequest(query, indexFrom, indexTo, testData.getResources());
}

@RequestMapping(value=Endpoints.GET_LOCATIONS, method=RequestMethod.GET, produces = {MediaType.APPLICATION_JSON_VALUE})
@ResponseStatus(HttpStatus.OK)
public @ResponseBody SuggestionsPayload getLocations(@RequestParam(value="q") String query, @RequestParam int indexFrom, @RequestParam int indexTo) {
    return makeRequest(query, indexFrom, indexTo, testData.getLocations());
}

private SuggestionsPayload makeRequest(String query, int indexFrom, int indexTo, String[] data) {
    int count = 0;
    final List possibilities = new ArrayList();
    for (final String resourceName: data) {
        final String key = resourceName.toLowerCase();
        final int has = key.indexOf(query.toLowerCase());

        if (!query.isEmpty() && (query.equals("*") || has >= 0)) {
            final SuggestionOption possibility = new SuggestionOption();
            possibility.setDisplayName(resourceName);
            possibility.setValue(resourceName);   // shouldn't this be a unique id?  e.g., resourceid
            possibilities.add(possibility);
            count++;
        }
    }

    final List options = new ArrayList();
    if (possibilities.size() > 0) {
        final int end = count - 1 > indexTo ? indexTo : count - 1;
        for (int i = indexFrom; i <= end; i++) {
            options.add(possibilities.get(i));
        }
        // sort the suggestions by display name
        Collections.sort(options, new Comparator() {

            @Override
            public int compare(SuggestionOption o1, SuggestionOption o2) {
                final int comparison = o1.getDisplayName().compareTo(o2.getDisplayName());
                return comparison;
            }

        });
    }

    final SuggestionsPayload result = new SuggestionsPayload();
    result.setTotalSize(count);
    result.setOptions(options);
    return result;
}

}

PAYLOAD

public class SuggestionsPayload {

@JsonProperty("TotalSize")
@JsonSerialize @JsonDeserialize
private int totalSize;
@JsonProperty("Options")
@JsonSerialize @JsonDeserialize
private List options;

public int getTotalSize() {
    return totalSize;
}

public void setTotalSize(int totalSize) {
    this.totalSize = totalSize;
}

public List getOptions() {
    return options;
}

public void setOptions(List options) {
    this.options = options;
}

public static class SuggestionOption {

    @JsonProperty("Value")
    @JsonSerialize @JsonDeserialize
    private String value;
    @JsonProperty("DisplayName")
    @JsonSerialize @JsonDeserialize
    private String displayName;

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public String getDisplayName() {
        return displayName;
    }

    public void setDisplayName(String displayName) {
        this.displayName = displayName;
    }

}
}

WEB.XML


    



    contextClass
    org.springframework.web.context.support.AnnotationConfigWebApplicationContext




    contextConfigLocation
    com.spp.mui.gwt.server.config.WebAppContextExperimental




    spring.profiles.default
    standard




    org.springframework.web.context.ContextLoaderListener




    
        org.springframework.web.context.request.RequestContextListener
    




    characterEncodingFilter
    org.springframework.web.filter.CharacterEncodingFilter
    
        encoding
        UTF-8
    
    
        forceEncoding
        true
    



    characterEncodingFilter
    /*




    hiddenHttpMethodFilter
    org.springframework.web.filter.HiddenHttpMethodFilter



    hiddenHttpMethodFilter
    /*







    appServlet
    org.springframework.web.servlet.DispatcherServlet
    
               
        contextConfigLocation
        
    
    1



    appServlet
    /



    Application.html



    0

CONFIGURATION

@Configuration
@Import(value={ AopConfig.class, GwtServiceConfig.class, ComponentConfig.class, MvcConfig.class })
public class WebAppContextExperimental {
// context used for web application

}

and within my MvcConfig I had to make sure to add these (particularly the registry entries for GWT support so Spring's DispatcherServlet would allow requests for code gen'd resources)

// serve static resources

@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
    // i.e., images, JS, and CSS
    registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
    // i.e., GWT module code-generated resources
    registry.addResourceHandler("/*").addResourceLocations("/");
    registry.addResourceHandler("/EMKT/**").addResourceLocations("/EMKT/");
}

@Override
public void configureMessageConverters(List> converters) {
    converters.add(new MappingJacksonHttpMessageConverter());
}

Spring MVC, REST, JSON, and DispatcherServlet and @RequestMapping

Answers (1)

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