Add Spring Session WebFlux sample

See gh-11055

spring-boot-samples/spring-boot-sample-session-webflux/src/main/java/sample/session/HelloRestController.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2012-2017 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
+ *
+ *      http://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 sample.session;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.server.WebSession;
+
+@RestController
+public class HelloRestController {
+
+	@GetMapping("/")
+	String sessionId(WebSession session) {
+		return session.getId();
+	}
+
+}

spring-boot-samples/spring-boot-sample-session-webflux/src/main/java/sample/session/SampleSessionWebFluxApplication.java

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+/*
+ * Copyright 2012-2017 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
+ *
+ *      http://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 sample.session;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.security.config.web.server.ServerHttpSecurity;
+import org.springframework.security.core.userdetails.MapReactiveUserDetailsService;
+import org.springframework.security.core.userdetails.ReactiveUserDetailsService;
+import org.springframework.security.core.userdetails.User;
+import org.springframework.security.web.server.SecurityWebFilterChain;
+import org.springframework.security.web.server.context.WebSessionServerSecurityContextRepository;
+
+@SpringBootApplication
+public class SampleSessionWebFluxApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SampleSessionWebFluxApplication.class);
+	}
+
+	@Bean
+	public ReactiveUserDetailsService userDetailsRepository() {
+		return new MapReactiveUserDetailsService(User.withDefaultPasswordEncoder()
+				.username("user").password("password").roles("USER").build());
+	}
+
+	@Bean
+	public SecurityWebFilterChain springSecurityFilterChain(ServerHttpSecurity http) {
+		// @formatter:off
+		return http
+			.authorizeExchange()
+				.anyExchange().authenticated()
+				.and()
+			.httpBasic().securityContextRepository(new WebSessionServerSecurityContextRepository())
+				.and()
+			.formLogin()
+				.and()
+			.build();
+		// @formatter:on
+	}
+
+}