Using Restful web service in Liferay

Consume Liferay JSON service for GET requests

Liferay exposes many default and custom services available to other systems via JSON. To explore services on a particular liferay instance, use a given URL - A local instance in this case:

https://localhost:8080/api/jsonws/

Select the required service, consume the service with the given syntax and parameters:

/user/get-user-by-email-address

Use companyId and emailAddress to retrieve the user with the expected datatypes, as well as possible exceptions to be handled by the consumer.

The following example consumes this service from a portlet. The given utility class method makes a call to the webservice, passing the necessary arguments:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

import sun.misc.BASE64Encoder;

import com.liferay.portal.kernel.util.StringUtil;
import com.liferay.portal.theme.ThemeDisplay;

public class WebServiceUtil {

public static String requestWebService(ThemeDisplay themeDisplay) {
    
    String url="https://localhost:8080/api/jsonws/user/get-user-by-email-address/company-id/{company-id}/email-address/{email-address}";
    
    String groupId= Long.toString(themeDisplay.getCompanyId());
    String userEmail="test@liferay.com";
    
    String[] searchList={"{company-id}","{email-address}"};
    String[] replList={groupId,userEmail};

    //Path params are replaced with args to make web service call
    url=StringUtil.replace(url, searchList, replList);
    
    System.out.println(url);
    StringBuilder sb = new StringBuilder();
    JSONObject jsonObject=new JSONObject();
    try
    {
        URL urlVal = new URL(url);
        HttpURLConnection conn = (HttpURLConnection) urlVal.openConnection();
        
        //The user credentials are directly used here only for the purpose of example,always fetech these details from an external props file.
        
        String uname ="test@liferay.com";
        String pswd="test";
        String authStr=uname+":"+pswd;
        
        //Encoding username+pswd to be added to request header for making web service             call
        String authStrEnc=new BASE64Encoder().encode(authStr.getBytes());

        /*Authorization type is set to consume web service
        and encoded combination is set in header to autheticate caller*/

        conn.setRequestMethod("GET");
        conn.setRequestProperty("Accept", "application/json");
        conn.setRequestProperty("Authorization", "Basic "+authStrEnc);
        
        BufferedReader brf = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        
        JSONParser json=new JSONParser();
        jsonObject=(JSONObject)json.parse(brf);
        
        
        int cp;
        while ((cp = brf.read()) != -1) {
          sb.append((char) cp);
        }
    }
    catch(IOException e)
    {
        System.out.println("Something went wrong while reading/writing in stream!!");
    }
    catch (ParseException e) {
        System.out.println("Parse error");
    }
    
    //For purpose of simplicity we have fetched one of the fields from JSON response
    return (String)jsonObject.get("firstName");
    
}

}