Consuming RESTful webservices with basic authentication.






We can consume Restful webservices many ways. But in this post I will show how to consume RESTful webservices using jersey rest client, which has basic authentication.

What we need?

1. RESTful url.
2. Jersey Client jar.
3. Jackson data Mapper jar.

1. RESTful url

Build a RESTful webservices using jersey or spring. If you do not know how to build a webservices please refer my previous post.

2. Jersey Core Client jar

Download the jar file from maven repository or use the below maven dependency

	com.sun.jersey
	jersey-client
	1.19

3. Jackson data Mapper jar

Download the jar file from maven repository or use the below maven dependency

			org.codehaus.jackson
			jackson-jaxrs
			1.9.13
		

Client code to access RESTful webservices.

RestClient.java

Rest client is the common class which has get and post method.

package javaant.rest;

import java.io.IOException;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
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.api.client.filter.HTTPBasicAuthFilter;

public class RestClient {
	//////////change the rest user and password
	static String rest_password="yourpassword";
	static String rest_user="user id";
	public static  T post(String url,T data,T t){
		try {
		Client client = Client.create();
		
		 client.addFilter(new HTTPBasicAuthFilter(rest_user, rest_password));
		WebResource webResource = client.resource(url);
		
		ClientResponse response = webResource.type("application/json").post(ClientResponse.class, JsonUtils.javaToJson(data));
 
		if (response.getStatus() != 200) {
			throw new RuntimeException("Failed : HTTP error code : "
			     + response.getStatus());
		}
		String output = response.getEntity(String.class);
		System.out.println("Response===post="+output);
		
			t=(T)JsonUtils.jsonToJavaObject(output, t.getClass());
		} catch (JsonParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (JsonMappingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return t;
	}
	public static  T get(String url,T t)
	{
		 try {
		Client client = Client.create();
		 
		WebResource webResource = client.resource(url);
		 client.addFilter(new HTTPBasicAuthFilter(rest_user, rest_password));
		ClientResponse response = webResource.accept("application/json").get(ClientResponse.class);
 
		if (response.getStatus() != 200) {
		   throw new RuntimeException("Failed : HTTP error code : "
			+ response.getStatus());
		}
 
		String output = response.getEntity(String.class);
		System.out.println("Response===get="+output);
			t=(T)JsonUtils.jsonToJavaObject(output, t.getClass());
		} catch (JsonParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (JsonMappingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return t;
	}

}

AccessRestClient.java

This class access the rest url using the RestClient class.

package javaant.rest;
import java.util.ArrayList;
import java.util.List;
public class AccessRestClient {
	String baseUrl="http://javamad.com/javamad-webservices-1.0";
	public void getQuestions(){
	
		MyResponse gqResponse=new MyResponse();
		gqResponse =RestClient.get(baseUrl+"/v1/questionAnswerService/questions?questionType=2",gqResponse);
		List qList=new ArrayList();
		qList=(List) gqResponse.getData();
		
	}
	
	
	public void postQuestions(){
		MyResponse pqResponse=new MyResponse();
		PostQuestionRequest pqRequest=new PostQuestionRequest();
		pqRequest.setQuestion("Post questions form rest client");
		pqRequest.setQuestionType("2");
		pqRequest.setUser_id("2");
		//Map m= new HashMap();
		pqResponse =(MyResponse) RestClient.post(baseUrl+"/v1/questionAnswerService/questions",pqRequest,pqResponse);
		
	}
	public static void main(String ar[]){
	AccessRestClient ac= new AccessRestClient();
		
		/////////////////post
		ac.postQuestions();
		//////////////////get
		ac.getQuestions();
		
	}

}