How to configure Spring RestTemplate with SSL (in Spring @MVC)

Question

I want to configure my Spring @MVC stub application's Spring RestTemplate with SSL for communicate to REST base https application, that deployed on Tomcat server (Spring 3, Tomcat 7). I have done up to now my works by refer this link. Now I have not any idea how to use these generated certificates with Spring RestTemplate, Can anyone have some idea please help me. Thanks. Up to now things I have done,

//Spring Security xml Configurations

   <http>
    <intercept-url pattern="/login" access="IS_AUTHENTICATED_ANONYMOUSLY" requires-channel="https"/>      
    <http-basic/></http> 

//Configurations for enable SSL with Tomcat

<Connector port="8443" protocol="org.apache.coyote.http11.Http11NioProtocol" maxThreads="200"
    scheme="https" secure="true" SSLEnabled="true"
    keystoreFile="C:\Users\Channa\.keystore" keystorePass="changeit"
    clientAuth="false" sslProtocol="TLS"/>

For generating Keys, certificates etc,

//Generate client and server keys:

F:\jdk1.6.0_23\bin>keytool -genkey -keystore keystore_client -alias clientKey -dname "CN=localhost, OU=Dev, O=MyBusiness, L=Colombo, S=Westen, C=SL"
F:\jdk1.6.0_23\bin>keytool -genkey -keystore keystore_server -alias serverKey -dname "CN=localhost, OU=Dev, O=MyBusiness, L=Colombo, S=Westen, C=SL"

//Generate client and server certificates:

F:\jdk1.6.0_23\bin>keytool -export -alias clientKey -rfc -keystore keystore_client > client.cert F:\jdk1.6.0_23\bin>keytool -export -alias serverKey -rfc -keystore keystore_server > server.cert

//Import certificates to corresponding truststores:

F:\jdk1.6.0_23\bin>keytool -import -alias clientCert -file client.cert -keystore truststore_server F:\jdk1.6.0_23\bin>keytool -import -alias serverCert -file server.cert -keystore truststore_client

//Spring RestTemplate configurations

<!--Http client-->
<bean id="httpClient" class="org.apache.commons.httpclient.HttpClient">
    <constructor-arg ref="httpClientParams"/>
    <property name="state" ref="httpState"/>
</bean>

<!--Http state-->
<bean id="httpState" class="com.org.imc.test.stub.http.CustomHttpState">
    <property name="credentials" ref="usernamePasswordCredentials"/>
</bean>

<!--User name password credentials-->
<bean id="usernamePasswordCredentials" class="org.apache.commons.httpclient.UsernamePasswordCredentials"/>

<!--Http client-->
<bean id="httpClientFactory" class="org.springframework.http.client.CommonsClientHttpRequestFactory">
    <constructor-arg ref="httpClient"/>
</bean>

<!--RestTemplate-->
<bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
    <constructor-arg ref="httpClientFactory"/>
</bean>

//Https URL going to access

ResponseEntity<User> rECreateUser = restTemplate.postForEntity("https://127.0.0.1:8443/skeleton-1.0/login", user, User.class);

//Exception currently I got:

org.springframework.web.client.ResourceAccessException: I/O error: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target; nested exception is javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

Answer 1

This is because SSL certificate of the service you are calling is not signed by a trusted certificate authority. The workaround is to import the certificate into the certificate trust store (cacerts) of your JRE.

1. download the cert by opening the URL in a browser, click the lock icon in the browser's address bar.

2. Once you have a .cer file execute the below command

   keytool -import -keystore jdk1.8.0_77/jre/lib/security/cacerts -file ~/test.cer -alias test
   

Answer 2

Variant for Spring Boot:

1. Add dependency:

    implementation 'org.apache.httpcomponents:httpclient:4.5'    
   

2. Provide RestTemplate bean:

@Bean
private RestTemplate restTemplate() {
        SSLContext sslContext = buildSslContext();
        SSLConnectionSocketFactory socketFactory = new SSLConnectionSocketFactory(sslContext);

        HttpClient httpClient = HttpClients.custom()
                .setSSLSocketFactory(socketFactory)
                .build();

        HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory(httpClient);

        return new RestTemplate(factory);
    }

private SSLContext buildSslContext() {
        try {
            char[] keyStorePassword = sslProperties.getKeyStorePassword();
            return new SSLContextBuilder()
                    .loadKeyMaterial(
                            KeyStore.getInstance(new File(sslProperties.getKeyStore()), keyStorePassword),
                            keyStorePassword
                    ).build();
        } catch (Exception ex) {
            throw new IllegalStateException("Unable to instantiate SSL context", ex);
        } finally {
            sslProperties.setKeyStorePassword(null);
            sslProperties.setTrustStorePassword(null);
        }
    }

3. Provide required SSL properties in your application.properties or application.yaml file:

server:
    ssl:
        enabled: true
        key-store: /path/to/key.keystore
        key-store-password: password
        key-alias: alias
        trust-store: /path/to/truststore
        trust-store-password: password

That's it. Now you can see your Tomcat is starting on 8080 (or another port) (https). Alternatively, you can use my spring boot starter