Simple CAS Java Rest Client

CasLogin.java

package com.bmchild.pocrestclient;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.logging.Logger;

import javax.security.sasl.AuthenticationException;

public class CasLogin {
	
	private static final Logger LOGGER = Logger.getLogger(CasLogin.class.getName());
	
	private String username;
	private String password;
	private String casUrl;
	private RestClient restClient;
	
	public CasLogin(String username, String password, String casUrl) {
		this.username = username;
		this.password = password;
		this.casUrl = casUrl;
		restClient = new RestClient();
	}
	
	public String getServiceTicket(String serviceUrl) throws IOException {
		// get TGT
        String location = getTicketGrantingTicket(username, password);
        
        // get SGT
        return getServiceGrantingTicket(location, serviceUrl);
		
	}
	
	/**
	 * With the TGT location and service url this will get the SGT
	 * @param tgtLocation
	 * @param serviceUrl
	 * @return
	 * @throws IOException
	 */
	private String getServiceGrantingTicket(String tgtLocation, String serviceUrl) throws IOException {
		Map<String,Object> params = new LinkedHashMap<>();
        params.put("service", serviceUrl);
        params.put("method", "POST");
        
        
        HttpURLConnection conn = restClient.post(tgtLocation, params);
        StringBuilder responseBuilder = new StringBuilder();
        BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));
		String input;
		while ((input = in.readLine()) != null) {
			responseBuilder.append(input);
		}
		in.close();
		
		String response = responseBuilder.toString();
		LOGGER.info("SGT -> " + response);
		 
		return response;
	}
	
	/**
	 * Gets the TGT for the given username and password
	 * @param username
	 * @param password
	 * @return
	 * @throws IOException
	 */
	private String getTicketGrantingTicket(String username, String password) throws IOException {
		Map<String,Object> params = new LinkedHashMap<>();
		params.put("username", username);
		params.put("password", password);
		HttpURLConnection conn = restClient.post(casUrl, params);
		
        if(conn.getResponseCode() == 400) {
        	throw new AuthenticationException("bad username or password");
        }
        String location = conn.getHeaderField("Location");
        LOGGER.info("TGT LOCATION -> " + location);
        return location;
	}
	
}

Main.java

package com.bmchild.pocrestclient;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Logger;

public class Main {
	
	private static final Logger LOGGER = Logger.getLogger(Main.class.getName());
	private static final String CAS_URL = "https://casserver.com/sso/v1/tickets";
	private static final String REST_BASE_URL = "http://restservice.com"; 
	
	public static void main(String[] args) throws IOException {
		
		CasLogin casLogin = new CasLogin("user", "pass", CAS_URL);
		RestClient client = new RestClient();
		
		/* example GET */
		Main main = new Main();
		String getSimple =  REST_BASE_URL + "/rest/api/v1/messages";
		main.printContent( client.get(getSimple + "?ticket=" + casLogin.getServiceTicket(getSimple)) );
		
		String getParams =  REST_BASE_URL + "/rest/api/v1/messages?page=1";
		main.printContent( client.get(getParams + "&ticket=" + casLogin.getServiceTicket(getParams)));
		
		String getSimple2 = REST_BASE_URL + "/rest/api/v1/messages/4405078";
		main.printContent( client.get(getSimple2 + "?ticket=" + casLogin.getServiceTicket(getSimple2)));
		
		/* Example POST */
		// see https://groups.google.com/forum/#!searchin/jasig-cas-user/post$20to$20rest$20resource/jasig-cas-user/NWmFahj9usk/YBECPJULN3sJ
		// looks like <property name="redirectAfterValidation" value="true" /> should be false in our webapp's spring security context (casContext.xml)
		String postMessage = REST_BASE_URL + "/rest/api/v1/messages";
		Map<String, Object> params = new HashMap<String, Object>();
		params.put("body", "message body");
		params.put("toAddress", "11220"); // from address lookup
		params.put("subject", "message subject");
		main.printContent( client.post(postMessage + "?ticket=" + casLogin.getServiceTicket(postMessage), params));
	}

	private void printContent(HttpURLConnection con) {
		if (con != null) {

			try {
				
				LOGGER.info("Response Code -> " + con.getResponseCode());
				BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream()));

				String input;
				StringBuilder content = new StringBuilder();
				while ((input = br.readLine()) != null) {
					content.append(input);
				}
				br.close();
				LOGGER.info("Content -> " + content.toString());

			} catch (IOException e) {
				e.printStackTrace();
			}

		}

	}

}

RestClient.java

package com.bmchild.pocrestclient;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import java.util.Map;
import java.util.logging.Logger;

public class RestClient {
	
	private static final Logger LOGGER = Logger.getLogger(RestClient.class.getName());

	public URL createUrl(String url) throws MalformedURLException {
		return new URL(url);
	}
	
	public HttpURLConnection get(String url) throws IOException {
		LOGGER.info("Getting from url '" + url +"'");
		
		URL connectionUrl = createUrl(url);
		return (HttpURLConnection) connectionUrl.openConnection();
		
	}
	
	/**
	 * Helper Method to post data to the given url and with the given params
	 * @param url
	 * @param params
	 * @return
	 * @throws IOException
	 */
	public HttpURLConnection post(String url, Map<String, Object> params) throws IOException {
		LOGGER.info("Posting to url '" + url +"' w/ params '" + params.toString() + "'");
		
		URL connectionUrl = createUrl(url);
		byte[] postDataBytes = convertParamMapToBytes(params);
		HttpURLConnection conn = (HttpURLConnection)connectionUrl.openConnection();
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        conn.setRequestProperty("Content-Length", String.valueOf(postDataBytes.length));
        conn.setDoOutput(true);
        conn.getOutputStream().write(postDataBytes);
        return conn;
	}
	
	/**
	 * Helper method to convert a map to POST bytes
	 * @param params
	 * @return
	 * @throws UnsupportedEncodingException
	 */
	private byte[] convertParamMapToBytes(Map<String, Object> params) throws UnsupportedEncodingException {
		StringBuilder postData = new StringBuilder();
        for (Map.Entry<String,Object> param : params.entrySet()) {
            if (postData.length() != 0) postData.append('&');
            postData.append(URLEncoder.encode(param.getKey(), "UTF-8"));
            postData.append('=');
            postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8"));
        }
        return postData.toString().getBytes("UTF-8");
	}
	
}