querying dbpedia-spotlight using java

Question

I am trying to adapt one of the examples reported on DBpedia-SpotLight:

DBpediaSpotlightClient.java (required AnnotationClient.java)

Using this sample, a description is given and spotlight service is queried to retrieve an annotate response: Web Service

Well, to run this program is necessary to choose a path for input file (with description) and output file (with result): you can find this at the end of the source code.

File input = new File("...");
File output = new File("...");

Next, parameters it accepts are reported here:

GetMethod getMethod = new GetMethod(API_URL + "rest/annotate/?" +
                "confidence=" + CONFIDENCE
                + "&support=" + SUPPORT
                + "&text=" + URLEncoder.encode(text.text(), "utf-8"));
getMethod.addRequestHeader(new Header("Accept", "application/json"));
spotlightResponse = request(getMethod);

Where I suppose it stores parameters passed to listen spotlight service.

As written at Web Service I would use also other options (example the sparql parameter) and use other query methods like spotting or candidates ("rest/spot/?", "rest/candidates/?") but I don't know how I can proceed.

How can I modify it? Is it necessary another file?

Thank you!

Edited:

Please, give a look at the code I'm running (API_URL is "http://spotlight.dbpedia.org/"):

        LOG.info("Querying API.");
        String spotlightResponse;
        try {
            GetMethod getMethod = new GetMethod(API_URL + "rest/candidates?" +
                    "confidence=" + CONFIDENCE
                    + "&support=" + SUPPORT
                    + "&text=" + URLEncoder.encode(text.text(), "utf-8"));
            getMethod.addRequestHeader(new Header("Accept", "application/json"));

            spotlightResponse = request(getMethod);
        } catch (UnsupportedEncodingException e) {
            throw new AnnotationException("Could not encode text.", e);
        }

I tried what you suggested but I get back this kind of error for each request:

INFO 2014-01-28 12:40:41,578 main [DBpediaSpotlightClient] - Querying API.
gen 28, 2014 12:40:54 PM org.apache.commons.httpclient.HttpMethodBase getRespons
eBody
Avvertenza: Going to buffer response body of large or unknown size. Using getRes
ponseBodyAsStream instead is recommended.
ERROR 2014-01-28 12:40:55,089 main [DBpediaSpotlightClient] - org.dbpedia.spotli
ght.exceptions.AnnotationException: Received invalid response from DBpedia Spotl
ight API.
org.dbpedia.spotlight.exceptions.AnnotationException: Received invalid response
from DBpedia Spotlight API.
        at org.dbpedia.spotlight.evaluation.external.DBpediaSpotlightClient.extr
act(DBpediaSpotlightClient.java:74)
        at org.dbpedia.spotlight.evaluation.external.AnnotationClient.saveExtrac
tedEntitiesSet(AnnotationClient.java:138)
        at org.dbpedia.spotlight.evaluation.external.AnnotationClient.evaluateMa
nual(AnnotationClient.java:168)
        at org.dbpedia.spotlight.evaluation.external.AnnotationClient.evaluate(A
nnotationClient.java:164)
        at org.dbpedia.spotlight.evaluation.external.DBpediaSpotlightClient.main
(DBpediaSpotlightClient.java:112)
 INFO 2014-01-28 12:40:55,110 main [DBpediaSpotlightClient] - Extracted entities
 from 5 text items, with 0 successes and 5 errors.
 INFO 2014-01-28 12:40:55,110 main [DBpediaSpotlightClient] - Results saved to:
C:\Users\Alberto\Documents\projects\OmniTourist\apache jena\org\dbpedia\spotligh
t\evaluation\external\output.txt
 INFO 2014-01-28 12:40:55,114 main [DBpediaSpotlightClient] - Average extraction
 time: 0.0 ms

Thank you again!

Answer 1

In order to use other methods, you should change the GetMethod. E.g:

// "rest/candidates/?"

GetMethod getMethod = new GetMethod(API_URL + "rest/candidates?" +
                "confidence=" + CONFIDENCE
                + "&support=" + SUPPORT
                + "&text=" + URLEncoder.encode(text.text(), "utf-8"));

Etc.