exception when invoking methods on twitterTemplate

Hi to all,

I am developing an example for accessing Twitter. All goes well when I do the oAuth "dance". At the end when I try to invoke the available methods on the TwitterTemplate I get:

Quote:

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Exception in thread "main" org.springframework.web.client.RestClientException : Could not extract response: no suitable HttpMessageConverter found for response type [java.util.Map] and content type [application/json;charset=utf-8]
at org.springframework.web.client.HttpMessageConverte rExtractor.extractData(HttpMessageConverterExtract or.java:77)
at org.springframework.web.client.RestTemplate$Respon seEntityResponseExtractor.extractData(RestTemplate .java:619)
at org.springframework.web.client.RestTemplate$Respon seEntityResponseExtractor.extractData(RestTemplate .java:1)
at org.springframework.web.client.RestTemplate.doExec ute(RestTemplate.java:446)
at org.springframework.web.client.RestTemplate.execut e(RestTemplate.java:401)
at org.springframework.web.client.RestTemplate.postFo rEntity(RestTemplate.java:302)
at org.springframework.social.twitter.TwitterTemplate .updateStatus(TwitterTemplate.java:134)
at xx.xxxxxxx.SpringSocialApp.TwitterApp.main(Twitter App.java:121)

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I am getting this when I do both:

Code:

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String profileId = twitterTemplate.getProfileId();

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and

Code:

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twitterTemplate.updateStatus("yupiiiiii!");

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I found this post where one of the users mentions doing a try-catch block and ignoring the exception. This would go well for the updateStatus method (since I can see that the status gets updated). But creates a problem when you need to get something from the twitter server.

Any solution? None of you get this exception?!

If you need more details I would be glad to provide them.

Thanks,
Despot

SOME UPDATE:
It appears that the following converters are used:
[org.springframework.http.converter.ByteArrayHttpMe ssageConverter@9bc984, org.springframework.http.converter.StringHttpMessa geConverter@1cb2795, org.springframework.http.converter.ResourceHttpMes sageConverter@93bca2, org.springframework.http.converter.xml.SourceHttpM essageConverter@1455d1c, org.springframework.http.converter.xml.XmlAwareFor mHttpMessageConverter@e3ffdf, org.springframework.http.converter.xml.Jaxb2RootEl ementHttpMessageConverter@b3a5a0]

I found a piece of code in the source when the RestTemplate is created:

Code:

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        private static final boolean jaxb2Present =
                        ClassUtils.isPresent("javax.xml.bind.Binder", RestTemplate.class.getClassLoader());

        private static final boolean jacksonPresent =
                        ClassUtils.isPresent("org.codehaus.jackson.map.ObjectMapper", RestTemplate.class.getClassLoader()) &&
                                        ClassUtils.isPresent("org.codehaus.jackson.JsonGenerator", RestTemplate.class.getClassLoader());

        private static boolean romePresent =
                        ClassUtils.isPresent("com.sun.syndication.feed.WireFeed", RestTemplate.class.getClassLoader());
        public RestTemplate() {
                this.messageConverters.add(new ByteArrayHttpMessageConverter());
                this.messageConverters.add(new StringHttpMessageConverter());
                this.messageConverters.add(new ResourceHttpMessageConverter());
                this.messageConverters.add(new SourceHttpMessageConverter());
                this.messageConverters.add(new XmlAwareFormHttpMessageConverter());
                if (jaxb2Present) {
                        this.messageConverters.add(new Jaxb2RootElementHttpMessageConverter());
                }
                if (jacksonPresent) {
                        this.messageConverters.add(new MappingJacksonHttpMessageConverter());
                }
                if (romePresent) {
                        this.messageConverters.add(new AtomFeedHttpMessageConverter());
                        this.messageConverters.add(new RssChannelHttpMessageConverter());
                }
        }

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A wild guess: since the exception is all about not being able to resolve application/json content type, and on the other hand I cannot see the Jackson converter in the available converters, does this mean I am missing a library? Is spring-social-core.jar enough or should I include some other libraries in the project?

Hi,

I got the same problem and managed to fix it by including the Jackson Library

http://jackson.codehaus.org/

Yes, Jackson is a required because the data coming back from Twitter is in JSON format.

Under the covers of TwitterTemplate is RestTemplate, which uses implementations of HttpMessageConverter to convert data coming back from a REST service into some type that the caller asks for. There will only be a JSON message converter if Jackson is in the classpath. Otherwise, without a suitable JSON message converter registered, you'll get an exception saying that there's no suitable message converter to convert between application/json and whatever type RestTemplate is asked to give back.

Thanks for your replies! I am unable to check this because of problems with the maven repository, but I am sure it will work. I will inform you about my progress!

Regards,
Despot

Adding the following jackson dependancy fixed my problem:

Code:

---

                <dependency>
                        <groupId>org.codehaus.jackson</groupId>
                        <artifactId>jackson-mapper-asl</artifactId>
                        <version>[1.0,2.0)</version> <!-- 1.0 <= x < 2.0 so all versions higher than 1.0 including 1.0 but lower
                                than (and excluding) 2.0, since the version of jackson 2.0 might not be compatible. -->
                </dependency>

---

Regards,
Despot