Extract code samples from docs

See gh-6313

spring-boot-project/spring-boot-docs/build.gradle

@@ -86,6 +86,7 @@ dependencies {
 	implementation("org.slf4j:jul-to-slf4j")
 	implementation("org.springframework:spring-test")
 	implementation("org.springframework:spring-web")
+	implementation("org.springframework:spring-webmvc")
 	implementation("org.springframework:spring-webflux")
 	implementation("org.springframework.data:spring-data-couchbase")
 	implementation("org.springframework.data:spring-data-neo4j")

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/externalizedconfiguration/ThirdPartyConfiguration.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.externalizedconfiguration;
+
+//tag::code[]
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration(proxyBeanMethods = false)
+public class ThirdPartyConfiguration {
+
+	@Bean
+	@ConfigurationProperties(prefix = "another")
+	public AnotherComponent anotherComponent() {
+		return new AnotherComponent();
+	}
+
+}
+// end::code[]
+
+class AnotherComponent {
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/externalizedconfiguration/enable/MyApplication.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.externalizedconfiguration.enable;
+
+//tag::code[]
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.context.properties.ConfigurationPropertiesScan;
+
+@SpringBootApplication
+@ConfigurationPropertiesScan({ "com.example.app", "org.acme.another" })
+public class MyApplication {
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/externalizedconfiguration/enable/MyConfiguration.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.externalizedconfiguration.enable;
+
+//tag::code[]
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration(proxyBeanMethods = false)
+@EnableConfigurationProperties(AcmeProperties.class)
+public class MyConfiguration {
+
+}
+// end::code[]
+
+class AcmeProperties {
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/externalizedconfiguration/merge/list/AcmeProperties.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.externalizedconfiguration.merge.list;
+
+//tag::code[]
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+@ConfigurationProperties("acme")
+public class AcmeProperties {
+
+	private final List<MyPojo> list = new ArrayList<>();
+
+	public List<MyPojo> getList() {
+		return this.list;
+	}
+
+}
+// end::code[]
+
+class MyPojo {
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/externalizedconfiguration/merge/map/AcmeProperties.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.externalizedconfiguration.merge.map;
+
+//tag::code[]
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+@ConfigurationProperties("acme")
+public class AcmeProperties {
+
+	private final Map<String, MyPojo> map = new LinkedHashMap<>();
+
+	public Map<String, MyPojo> getMap() {
+		return this.map;
+	}
+
+}
+// end::code[]
+
+class MyPojo {
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/externalizedconfiguration/relaxed/OwnerProperties.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.externalizedconfiguration.relaxed;
+
+//tag::code[]
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+@ConfigurationProperties(prefix = "acme.my-project.person")
+public class OwnerProperties {
+
+	private String firstName;
+
+	public String getFirstName() {
+		return this.firstName;
+	}
+
+	public void setFirstName(String firstName) {
+		this.firstName = firstName;
+	}
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/externalizedconfiguration/use/MyService.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.externalizedconfiguration.use;
+
+//tag::code[]
+import org.springframework.stereotype.Service;
+
+@Service
+public class MyService {
+
+	private final AcmeProperties properties;
+
+	public MyService(AcmeProperties properties) {
+		this.properties = properties;
+	}
+
+	public void openConnection() {
+		Server server = new Server(this.properties.getRemoteAddress());
+		server.start();
+		// ...
+	}
+
+	// ...
+
+}
+// end::code[]
+
+class AcmeProperties {
+
+	Object getRemoteAddress() {
+		return null;
+	}
+
+}
+
+class Server {
+
+	Server(Object remoteAddress) {
+	}
+
+	void start() {
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/externalizedconfiguration/validate/AcmeProperties.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.externalizedconfiguration.validate;
+
+//tag::code[]
+import java.net.InetAddress;
+
+import javax.validation.constraints.NotNull;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.validation.annotation.Validated;
+
+@ConfigurationProperties(prefix = "acme")
+@Validated
+public class AcmeProperties {
+
+	@NotNull
+	private InetAddress remoteAddress;
+
+	public InetAddress getRemoteAddress() {
+		return this.remoteAddress;
+	}
+
+	public void setRemoteAddress(InetAddress remoteAddress) {
+		this.remoteAddress = remoteAddress;
+	}
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/externalizedconfiguration/validate/nested/AcmeProperties.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.externalizedconfiguration.validate.nested;
+
+//tag::code[]
+import java.net.InetAddress;
+
+import javax.validation.Valid;
+import javax.validation.constraints.NotEmpty;
+import javax.validation.constraints.NotNull;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.validation.annotation.Validated;
+
+@ConfigurationProperties(prefix = "acme")
+@Validated
+public class AcmeProperties {
+
+	@NotNull
+	private InetAddress remoteAddress;
+
+	@Valid
+	private final Security security = new Security();
+
+	public InetAddress getRemoteAddress() {
+		return this.remoteAddress;
+	}
+
+	public void setRemoteAddress(InetAddress remoteAddress) {
+		this.remoteAddress = remoteAddress;
+	}
+
+	public Security getSecurity() {
+		return this.security;
+	}
+
+	public static class Security {
+
+		@NotEmpty
+		private String username;
+
+		public String getUsername() {
+			return this.username;
+		}
+
+		public void setUsername(String username) {
+			this.username = username;
+		}
+
+	}
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/profiles/ProductionConfiguration.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.profiles;
+
+//tag::code[]
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Profile;
+
+@Configuration(proxyBeanMethods = false)
+@Profile("production")
+public class ProductionConfiguration {
+
+	// ...
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/HttpMessageConvertersConfiguration.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications;
+
+//tag::code[]
+import java.io.IOException;
+
+import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpInputMessage;
+import org.springframework.http.HttpOutputMessage;
+import org.springframework.http.converter.AbstractHttpMessageConverter;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.HttpMessageNotReadableException;
+import org.springframework.http.converter.HttpMessageNotWritableException;
+
+@Configuration(proxyBeanMethods = false)
+public class HttpMessageConvertersConfiguration {
+
+	@Bean
+	public HttpMessageConverters customConverters() {
+		HttpMessageConverter<?> additional = new AdditionalHttpMessageConverter();
+		HttpMessageConverter<?> another = new AnotherHttpMessageConverter();
+		return new HttpMessageConverters(additional, another);
+	}
+
+}
+// end::code[]
+
+class AdditionalHttpMessageConverter extends AbstractHttpMessageConverter<Object> {
+
+	@Override
+	protected boolean supports(Class<?> clazz) {
+		return false;
+	}
+
+	@Override
+	protected Object readInternal(Class<?> clazz, HttpInputMessage inputMessage)
+			throws IOException, HttpMessageNotReadableException {
+		return null;
+	}
+
+	@Override
+	protected void writeInternal(Object t, HttpOutputMessage outputMessage)
+			throws IOException, HttpMessageNotWritableException {
+	}
+
+}
+
+class AnotherHttpMessageConverter extends AdditionalHttpMessageConverter {
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/json/MyJsonComponent.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.json;
+
+//tag::code[]
+import java.io.IOException;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.ObjectCodec;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.JsonDeserializer;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+
+import org.springframework.boot.jackson.JsonComponent;
+
+@JsonComponent
+public class MyJsonComponent {
+
+	public static class Serializer extends JsonSerializer<MyObject> {
+
+		@Override
+		public void serialize(MyObject value, JsonGenerator jgen, SerializerProvider serializers) throws IOException {
+			jgen.writeStringField("name", value.getName());
+			jgen.writeNumberField("age", value.getAge());
+		}
+
+	}
+
+	public static class Deserializer extends JsonDeserializer<MyObject> {
+
+		@Override
+		public MyObject deserialize(JsonParser jsonParser, DeserializationContext ctxt)
+				throws IOException, JsonProcessingException {
+			ObjectCodec codec = jsonParser.getCodec();
+			JsonNode tree = codec.readTree(jsonParser);
+			String name = tree.get("name").textValue();
+			int age = tree.get("age").intValue();
+			return new MyObject(name, age);
+		}
+
+	}
+
+}
+// end::code[]
+
+class MyObject {
+
+	MyObject(String name, int age) {
+	}
+
+	String getName() {
+		return null;
+	}
+
+	Integer getAge() {
+		return null;
+
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/json/object/MyJsonComponent.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.json.object;
+
+//tag::code[]
+import java.io.IOException;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.ObjectCodec;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.SerializerProvider;
+
+import org.springframework.boot.jackson.JsonComponent;
+import org.springframework.boot.jackson.JsonObjectDeserializer;
+import org.springframework.boot.jackson.JsonObjectSerializer;
+
+@JsonComponent
+public class MyJsonComponent {
+
+	public static class Serializer extends JsonObjectSerializer<MyObject> {
+
+		@Override
+		protected void serializeObject(MyObject value, JsonGenerator jgen, SerializerProvider provider)
+				throws IOException {
+			jgen.writeStringField("name", value.getName());
+			jgen.writeNumberField("age", value.getAge());
+		}
+
+	}
+
+	public static class Deserializer extends JsonObjectDeserializer<MyObject> {
+
+		@Override
+		protected MyObject deserializeObject(JsonParser jsonParser, DeserializationContext context, ObjectCodec codec,
+				JsonNode tree) throws IOException {
+			String name = nullSafeValue(tree.get("name"), String.class);
+			int age = nullSafeValue(tree.get("age"), Integer.class);
+			return new MyObject(name, age);
+		}
+
+	}
+
+}
+// end::code[]
+
+class MyObject {
+
+	MyObject(String name, int age) {
+	}
+
+	String getName() {
+		return null;
+	}
+
+	Integer getAge() {
+		return null;
+
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/servlet/CorsConfiguration.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.servlet;
+
+//tag::code[]
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.config.annotation.CorsRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+@Configuration(proxyBeanMethods = false)
+public class CorsConfiguration {
+
+	@Bean
+	public WebMvcConfigurer corsConfigurer() {
+		return new WebMvcConfigurer() {
+
+			@Override
+			public void addCorsMappings(CorsRegistry registry) {
+				registry.addMapping("/api/**");
+			}
+
+		};
+	}
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/servlet/ErrorPageConfiguration.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.servlet;
+
+//tag::code[]
+import org.springframework.boot.web.server.ErrorPage;
+import org.springframework.boot.web.server.ErrorPageRegistrar;
+import org.springframework.boot.web.server.ErrorPageRegistry;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpStatus;
+
+@Configuration
+public class ErrorPageConfiguration {
+
+	@Bean
+	public ErrorPageRegistrar errorPageRegistrar() {
+		return this::registerErrorPages;
+	}
+
+	private void registerErrorPages(ErrorPageRegistry registry) {
+		registry.addErrorPages(new ErrorPage(HttpStatus.BAD_REQUEST, "/400"));
+	}
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/servlet/MyControllerAdvice.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.servlet;
+
+//tag::code[]
+import javax.servlet.RequestDispatcher;
+import javax.servlet.http.HttpServletRequest;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
+
+@ControllerAdvice(basePackageClasses = AcmeController.class)
+public class MyControllerAdvice extends ResponseEntityExceptionHandler {
+
+	@ResponseBody
+	@ExceptionHandler(MyException.class)
+	ResponseEntity<?> handleControllerException(HttpServletRequest request, Throwable ex) {
+		HttpStatus status = getStatus(request);
+		return new ResponseEntity<>(new MyErrorBody(status.value(), ex.getMessage()), status);
+	}
+
+	private HttpStatus getStatus(HttpServletRequest request) {
+		Integer code = (Integer) request.getAttribute(RequestDispatcher.ERROR_STATUS_CODE);
+		HttpStatus status = HttpStatus.resolve(code);
+		return (status != null) ? status : HttpStatus.INTERNAL_SERVER_ERROR;
+	}
+
+}
+// end::code[]
+
+class AcmeController {
+
+}
+
+class MyException extends RuntimeException {
+
+}
+
+class MyErrorBody {
+
+	MyErrorBody(int value, String message) {
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/servlet/MyErrorViewResolver.java

+/*
+ * Copyright 2012-2020 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 org.springframework.boot.docs.springbootfeatures.webapplications.servlet;
+
+//tag::code[]
+import java.util.Map;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.springframework.boot.autoconfigure.web.servlet.error.ErrorViewResolver;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.servlet.ModelAndView;
+
+public class MyErrorViewResolver implements ErrorViewResolver {
+
+	@Override
+	public ModelAndView resolveErrorView(HttpServletRequest request, HttpStatus status, Map<String, Object> model) {
+		// Use the request or status to optionally return a ModelAndView
+		if (status == HttpStatus.INSUFFICIENT_STORAGE) {
+			// We could add custom model values here
+			new ModelAndView("myview");
+		}
+		return null;
+	}
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/servlet/MyRestController.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.servlet;
+
+//tag::code[]
+import java.util.List;
+
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/users")
+public class MyRestController {
+
+	private final UserRepository userRepository;
+
+	private final CustomerRepository customerRepository;
+
+	public MyRestController(UserRepository userRepository, CustomerRepository customerRepository) {
+		this.userRepository = userRepository;
+		this.customerRepository = customerRepository;
+	}
+
+	@GetMapping("/{user}")
+	public User getUser(@PathVariable Long userId) {
+		return this.userRepository.findById(userId).get();
+	}
+
+	@GetMapping("/{user}/customers")
+	List<Customer> getUserCustomers(@PathVariable Long userId) {
+		return this.userRepository.findById(userId).map(this.customerRepository::findByUser).get();
+	}
+
+	@DeleteMapping("/{user}")
+	public void deleteUser(@PathVariable Long userId) {
+		this.userRepository.deleteById(userId);
+	}
+
+}
+// end::code[]
+
+interface UserRepository extends CrudRepository<User, Long> {
+
+}
+
+interface CustomerRepository extends CrudRepository<Customer, Long> {
+
+	List<Customer> findByUser(User user);
+
+}
+
+class User {
+
+	List<Customer> getCustomers() {
+		return null;
+	}
+
+}
+
+class Customer {
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/servlet/ServletFilterConfiguration.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.servlet;
+
+//tag::code[]
+import java.io.IOException;
+import java.util.EnumSet;
+
+import javax.servlet.DispatcherType;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.springframework.boot.web.servlet.FilterRegistrationBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.filter.GenericFilterBean;
+
+@Configuration
+public class ServletFilterConfiguration {
+
+	@Bean
+	public FilterRegistrationBean<MyFilter> myFilter() {
+		FilterRegistrationBean<MyFilter> registration = new FilterRegistrationBean<>(new MyFilter());
+		// ...
+		registration.setDispatcherTypes(EnumSet.allOf(DispatcherType.class));
+		return registration;
+	}
+
+}
+// end::code[]
+
+class MyFilter extends GenericFilterBean {
+
+	@Override
+	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
+			throws IOException, ServletException {
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/webflux/CodecConfiguration.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.webflux;
+
+//tag::code[]
+import org.springframework.boot.web.codec.CodecCustomizer;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.codec.ServerSentEventHttpMessageReader;
+
+@Configuration(proxyBeanMethods = false)
+public class CodecConfiguration {
+
+	@Bean
+	public CodecCustomizer myCodecCustomizer() {
+		return (configurer) -> {
+			configurer.registerDefaults(false);
+			configurer.customCodecs().register(new ServerSentEventHttpMessageReader());
+			// ...
+		};
+	}
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/webflux/CustomErrorWebExceptionHandler.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.webflux;
+
+//tag::code[]
+import reactor.core.publisher.Mono;
+
+import org.springframework.boot.autoconfigure.web.WebProperties.Resources;
+import org.springframework.boot.autoconfigure.web.reactive.error.AbstractErrorWebExceptionHandler;
+import org.springframework.boot.web.reactive.error.ErrorAttributes;
+import org.springframework.context.ApplicationContext;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.stereotype.Component;
+import org.springframework.web.reactive.function.server.RouterFunction;
+import org.springframework.web.reactive.function.server.RouterFunctions;
+import org.springframework.web.reactive.function.server.ServerRequest;
+import org.springframework.web.reactive.function.server.ServerResponse;
+import org.springframework.web.reactive.function.server.ServerResponse.BodyBuilder;
+
+@Component
+public class CustomErrorWebExceptionHandler extends AbstractErrorWebExceptionHandler {
+
+	public CustomErrorWebExceptionHandler(ErrorAttributes errorAttributes, Resources resources,
+			ApplicationContext applicationContext) {
+		super(errorAttributes, resources, applicationContext);
+	}
+
+	@Override
+	protected RouterFunction<ServerResponse> getRoutingFunction(ErrorAttributes errorAttributes) {
+		return RouterFunctions.route(this::acceptsXml, this::handleErrorAsXml);
+	}
+
+	private boolean acceptsXml(ServerRequest request) {
+		return request.headers().accept().contains(MediaType.APPLICATION_XML);
+	}
+
+	public Mono<ServerResponse> handleErrorAsXml(ServerRequest request) {
+		BodyBuilder builder = ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR);
+		// ... additional builder calls
+		return builder.build();
+	}
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/webflux/MyRestController.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.webflux;
+
+//tag::code[]
+import java.util.List;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import org.springframework.data.repository.reactive.ReactiveCrudRepository;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/users")
+public class MyRestController {
+
+	private final UserRepository userRepository;
+
+	private final CustomerRepository customerRepository;
+
+	public MyRestController(UserRepository userRepository, CustomerRepository customerRepository) {
+		this.userRepository = userRepository;
+		this.customerRepository = customerRepository;
+	}
+
+	@GetMapping("/{user}")
+	public Mono<User> getUser(@PathVariable Long userId) {
+		return this.userRepository.findById(userId);
+	}
+
+	@GetMapping("/{user}/customers")
+	Flux<Customer> getUserCustomers(@PathVariable Long userId) {
+		return this.userRepository.findById(userId).flatMapMany(this.customerRepository::findByUser);
+	}
+
+	@DeleteMapping("/{user}")
+	public void deleteUser(@PathVariable Long userId) {
+		this.userRepository.deleteById(userId);
+	}
+
+}
+// end::code[]
+
+interface UserRepository extends ReactiveCrudRepository<User, Long> {
+
+}
+
+interface CustomerRepository extends ReactiveCrudRepository<Customer, Long> {
+
+	Flux<Customer> findByUser(User user);
+
+}
+
+class User {
+
+	List<Customer> getCustomers() {
+		return null;
+	}
+
+}
+
+class Customer {
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/webflux/fn/RoutingConfiguration.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.webflux.fn;
+
+//tag::code[]
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.MediaType;
+import org.springframework.web.reactive.function.server.RequestPredicate;
+import org.springframework.web.reactive.function.server.RouterFunction;
+import org.springframework.web.reactive.function.server.ServerResponse;
+
+import static org.springframework.web.reactive.function.server.RequestPredicates.DELETE;
+import static org.springframework.web.reactive.function.server.RequestPredicates.GET;
+import static org.springframework.web.reactive.function.server.RequestPredicates.accept;
+import static org.springframework.web.reactive.function.server.RouterFunctions.route;
+
+@Configuration(proxyBeanMethods = false)
+public class RoutingConfiguration {
+
+	private static final RequestPredicate ACCEPT_JSON = accept(MediaType.APPLICATION_JSON);
+
+	@Bean
+	public RouterFunction<ServerResponse> monoRouterFunction(UserHandler userHandler) {
+		// @formatter:off
+		return route(
+				GET("/{user}").and(ACCEPT_JSON), userHandler::getUser).andRoute(
+				GET("/{user}/customers").and(ACCEPT_JSON), userHandler::getUserCustomers).andRoute(
+				DELETE("/{user}").and(ACCEPT_JSON), userHandler::deleteUser);
+		// @formatter:on
+	}
+
+}
+// end::code[]

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/springbootfeatures/webapplications/webflux/fn/UserHandler.java

+/*
+ * Copyright 2012-2021 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 org.springframework.boot.docs.springbootfeatures.webapplications.webflux.fn;
+
+//tag::code[]
+import reactor.core.publisher.Mono;
+
+import org.springframework.stereotype.Component;
+import org.springframework.web.reactive.function.server.ServerRequest;
+import org.springframework.web.reactive.function.server.ServerResponse;
+
+@Component
+public class UserHandler {
+
+	public Mono<ServerResponse> getUser(ServerRequest request) {
+		// ...
+		return ServerResponse.ok().build();
+	}
+
+	public Mono<ServerResponse> getUserCustomers(ServerRequest request) {
+		// ...
+		return ServerResponse.ok().build();
+	}
+
+	public Mono<ServerResponse> deleteUser(ServerRequest request) {
+		// ...
+		return ServerResponse.ok().build();
+	}
+
+}
+// end::code[]