accessing webservice using jersey client - rest

Question

package java4s;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
#Path("/vinay")
public class JsonFromRestful {
#POST
#Path("/{runID}/{tweetID}/{tweet : .*}")
#Produces(MediaType.TEXT_PLAIN)
public String sayPlainTextHello( #PathParam("runID") String rid,
#PathParam("tweetID") String tid,
#PathParam("tweet") String twt) throws IOException, InterruptedException {
StringBuffer resneel=new StringBuffer();
resneel.append(rid);
resneel.append(tid);
resneel.append(twt);
return return resneel.toString();
}
}
client test program
package neel;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;
import com.sun.jersey.core.util.MultivaluedMapImpl;
/*
* excerpt of the maven dependencies
<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-client</artifactId>
<version>1.19</version>
</dependency>
<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-core</artifactId>
<version>1.19</version>
</dependency>
*/
public class ClientTest {
public static void main(String[] args)
{
if(args.length != 4)
{
System.out.println("Incorrect parameters, usage:");
System.out.println("java -jar neelclienttest.jar run_id tweet_id tweet_to_annotate rest_api");
System.exit(1);
}
String runID = args[0];
String tweetID = args[1];
String tweet = args[2];
String uri = args[3];
try {
String annotations = annotate(uri, runID, tweetID, tweet);
System.out.println(annotations);
} catch (Exception e) {
e.printStackTrace();
}
}
public static String annotate(String uri, String runID, String tweetID, String tweet) throws Exception
{
Client client = Client.create();
WebResource webResource = client.resource(uri);
MultivaluedMap<String,String> params = new MultivaluedMapImpl();
params.add("RunID", runID);
params.add("TweetID", tweetID);
params.add("Tweet", tweet);
ClientResponse response = webResource.
accept(MediaType.TEXT_PLAIN_TYPE).
post(ClientResponse.class, params);
// check if status code != 200 OK
if ( response.getStatus() != 200 )
throw new Exception ("The REST interface has answered with an unexpected status code" + response.getStatus());
return response.getEntity(String.class);
}
}
here i am giving command line arguements runid tweetid tweet and the path is http://localhost/cen_neel/vinay/ but it is showing java.lang exception. we created a webservice and whatever i have given clienttest is for testing. i dont need any changes in clienttest. please help if there is any error in my program. i tested the same program with restclient plugin like below
http://localhost/cen_neel/vinay/r12/v23/Chennai and i am getting response back correctly.

Answer 1

Here post(ClientResponse.class, params);. you're trying to post the URI information into the body of the request. That's not where they belong. Actually, based on your resource method, there shouldn't be a body at all. You can simply pass an empty string.
Instead, how you should be building the request, is with .path() on the WebResource to append path segments
ClientResponse response = webResource
.path(runID)
.path(tweetID)
.path(tweet)
.accept(MediaType.TEXT_PLAIN_TYPE)
.post(ClientResponse.class, "");
It seems completely pointless though, the way you are doing it. Why not just pass the entire URI, like you are in the Rest Client.
Anyway, this is not really a good design overall. Here are some improvements I would make.
The actual tweet should not be in the URI. It should be posted in the body. To accept it in the body, simply don't annotate it with #PathParam for the tweet method parameter, and get rid of the path template {tweet : .*}. Then you can post(ClientReponse.class, tweet). You should also add #Consumes(MediaType.TEXT_PLAIN) to the resource method, and use type to create the request. i.e.
.accept(MediaType.TEXT_PLAIN_TYPE)
.type(MediaType.TEXT_PLAIN_TYPE)
.post(ClientResponse.class, tweet);
If you are trying to create a new tweet, the id, should not be in the template. The id should not exist yet. When the tweet is created, the server should notify the client with the newly created id of the tweet, with a Location header.