Accessing REST APIs from Java Service

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Learn how to access REST APIs using Java Service.

The steps include:

1. How to create a Java Service method to access a Rest Service.
2. How the Java Service can invoke the Rest Service to get the response.

Files Imported to Java Service

The following files were imported into the Java Service:

import javax.servlet.http.HttpServletRequest;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;
import com.wavemaker.runtime.security.SecurityService;
import com.wavemaker.runtime.service.annotations.ExposeToClient;
import com.wavemaker.runtime.service.annotations.HideFromClient;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import org.json.JSONObject;

Java Service Method

We will be using the following Java Service Method:

public ArrayList<String> restService(String origin, String destination) {
        ArrayList<String> directionList = new ArrayList<String>();
        try {
            URL url = new URL("http://maps.googleapis.com/maps/api/directions/xml?origin="+origin+"&destination="+destination+"&sensor=false");
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            if (conn.getResponseCode() != 200) {
                throw new RuntimeException("Failed : HTTP error code : "+ conn.getResponseCode());
            }
            BufferedReader br = new BufferedReader(new InputStreamReader((conn.getInputStream())));
            String output;
            while ((output = br.readLine()) != null) {while ((output = br.readLine()) != null) {
                if(output.contains("<html_instructions>"))      
                {
                    output = output.substring(output.indexOf(">")+1, output.indexOf("</html_instructions>"));
                    directionList.add(output);
                }               
            }} conn.disconnect();} 
         catch (MalformedURLException e) {
            e.printStackTrace();} 
         catch (IOException e) {
                 e.printStackTrace();}
         return directionList;
    }

See Also

How to send emails using Java Service
How to implement forgot password feature using Java Service
How to schedule a Java Service
How to accomplish Pre-Post Processing for a DB Service APIs