Add saml2-login java-configuration sample

Issue gh-10

servlet/java-configuration/saml2/login/src/main/java/example/MvcWebApplicationInitializer.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import javax.servlet.Filter;
+
+import org.springframework.web.filter.HiddenHttpMethodFilter;
+import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
+
+public class MvcWebApplicationInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
+
+	@Override
+	protected Class<?>[] getRootConfigClasses() {
+		return null;
+	}
+
+	@Override
+	protected Class<?>[] getServletConfigClasses() {
+		return new Class[] { ApplicationConfiguration.class };
+	}
+
+	@Override
+	protected String[] getServletMappings() {
+		return new String[] { "/" };
+	}
+
+	@Override
+	protected Filter[] getServletFilters() {
+		return new Filter[] { new HiddenHttpMethodFilter() };
+	}
+
+}