Spring OAuthClient setup for accessing a server with self signed certificate

gistfile1.txt

package com.synergygfs.cards;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.security.KeyStore;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.util.Arrays;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.TrustManagerFactory;

import org.springframework.core.io.ClassPathResource;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.security.oauth2.client.OAuth2ClientContext;
import org.springframework.security.oauth2.client.OAuth2RestTemplate;
import org.springframework.security.oauth2.client.resource.OAuth2ProtectedResourceDetails;
import org.springframework.security.oauth2.client.token.AccessTokenProvider;
import org.springframework.security.oauth2.client.token.AccessTokenProviderChain;
import org.springframework.security.oauth2.client.token.grant.client.ClientCredentialsAccessTokenProvider;
import org.springframework.security.oauth2.client.token.grant.code.AuthorizationCodeAccessTokenProvider;
import org.springframework.security.oauth2.client.token.grant.implicit.ImplicitAccessTokenProvider;
import org.springframework.security.oauth2.client.token.grant.password.ResourceOwnerPasswordAccessTokenProvider;


public class OAuth2RestTemplateSelfSignedCert extends OAuth2RestTemplate {
	private static final String CERTIFICATE_MWBACKEND_RESOURCE_PATH = "mwbackend.cer";

	public OAuth2RestTemplateSelfSignedCert(OAuth2ProtectedResourceDetails resource, OAuth2ClientContext context) {
		super(resource, context);
		try {
			SimpleSSLClientHttpRequestFactory requestFactory = new SimpleSSLClientHttpRequestFactory(hostNameVerifier(), certificate());
			
			this.setRequestFactory(requestFactory);

			AuthorizationCodeAccessTokenProvider authCodeTokenProvider = new AuthorizationCodeAccessTokenProvider();
			authCodeTokenProvider.setRequestFactory(requestFactory);

			ImplicitAccessTokenProvider implicitAccessTokenProvider = new ImplicitAccessTokenProvider();
			implicitAccessTokenProvider.setRequestFactory(requestFactory);

			ResourceOwnerPasswordAccessTokenProvider resourceOwnerPasswordAccessTokenProvider = new ResourceOwnerPasswordAccessTokenProvider();
			resourceOwnerPasswordAccessTokenProvider.setRequestFactory(requestFactory);

			ClientCredentialsAccessTokenProvider clientCredentialsAccessTokenProvider = new ClientCredentialsAccessTokenProvider();
			clientCredentialsAccessTokenProvider.setRequestFactory(requestFactory);

			this.setAccessTokenProvider(new AccessTokenProviderChain(
					Arrays.<AccessTokenProvider> asList(authCodeTokenProvider, implicitAccessTokenProvider,
							resourceOwnerPasswordAccessTokenProvider, clientCredentialsAccessTokenProvider)));

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

	protected static Certificate certificate() throws Exception {
		Certificate certificate = null;
		CertificateFactory cf = CertificateFactory.getInstance("X.509");
		ClassPathResource resource = new ClassPathResource(CERTIFICATE_MWBACKEND_RESOURCE_PATH);
		InputStream caInput = resource.getInputStream();
		try {
			certificate = cf.generateCertificate(caInput);
		} finally {
			caInput.close();
		}
		return certificate;
	}
	
	protected static HostnameVerifier hostNameVerifier() {
    	return new HostnameVerifier() {
			
			@Override
			public boolean verify(String hostname, SSLSession session) {
				return true;
			}
		};
    }
	
	protected class SimpleSSLClientHttpRequestFactory extends SimpleClientHttpRequestFactory {

		private final HostnameVerifier hostNameVerifier;
		private final Certificate certificate;

		public SimpleSSLClientHttpRequestFactory(final HostnameVerifier hostNameVerifier, Certificate certificate) {
			this.hostNameVerifier = hostNameVerifier;
			this.certificate = certificate;
		}

		@Override
		protected void prepareConnection(final HttpURLConnection connection, final String httpMethod)
				throws IOException {
			if (connection instanceof HttpsURLConnection) {
				((HttpsURLConnection) connection).setHostnameVerifier(hostNameVerifier);
				((HttpsURLConnection) connection).setSSLSocketFactory(initSSLContext().getSocketFactory());
			}
			super.prepareConnection(connection, httpMethod);
		}

		private SSLContext initSSLContext() {
			try {
				Certificate ca = certificate;

				// Create a KeyStore containing our trusted CAs
				String keyStoreType = KeyStore.getDefaultType();
				KeyStore keyStore = KeyStore.getInstance(keyStoreType);
				keyStore.load(null, null);
				keyStore.setCertificateEntry("ca", ca);

				// Create a TrustManager that trusts the CAs in our KeyStore
				String tmfAlgorithm = TrustManagerFactory.getDefaultAlgorithm();
				TrustManagerFactory tmf = TrustManagerFactory.getInstance(tmfAlgorithm);
				tmf.init(keyStore);

				// Create an SSLContext that uses our TrustManager
				SSLContext context = SSLContext.getInstance("TLS");
				context.init(null, tmf.getTrustManagers(), null);

				return context;

			} catch (final Exception ex) {
				return null;
			}
		}
	}

}