BAEL-2906 Functional Controllers in Spring MVC (#6972)

* BAEL-2906 Functional Controllers in Spring MVC

* BAEL-2906 Functional Controllers in Spring MVC

* BAEL-2906 Functional Controllers in Spring MVC

* BAEL-2906 Removed unnecessary files

* BAEL-2906 Removed project

* BAEL-2906 Removed comments

spring-boot-mvc-2/.gitignore

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+/target/
+!.mvn/wrapper/maven-wrapper.jar
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/build/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/

spring-boot-mvc-2/README.md

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+### Relevant Articles:
+
+- [Functional Controllers in Spring MVC]()

spring-boot-mvc-2/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>spring-boot-mvc-2</artifactId>
+    <name>spring-boot-mvc-2</name>
+    <packaging>jar</packaging>
+    <description>Module For Spring Boot MVC Web Fn</description>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>2.2.0.BUILD-SNAPSHOT</version>
+        <relativePath /> <!-- lookup parent from repository -->
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <configuration>
+                    <mainClass>com.baeldung.springbootmvc.SpringBootMvcFnApplication</mainClass>
+                    <layout>JAR</layout>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <repositories>
+        <repository>
+            <id>spring-snapshots</id>
+            <name>Spring Snapshots</name>
+            <url>https://repo.spring.io/snapshot</url>
+            <snapshots>
+                <enabled>true</enabled>
+            </snapshots>
+        </repository>
+        <repository>
+            <id>spring-milestones</id>
+            <name>Spring Milestones</name>
+            <url>https://repo.spring.io/milestone</url>
+        </repository>
+    </repositories>
+    <pluginRepositories>
+        <pluginRepository>
+            <id>spring-snapshots</id>
+            <name>Spring Snapshots</name>
+            <url>https://repo.spring.io/snapshot</url>
+            <snapshots>
+                <enabled>true</enabled>
+            </snapshots>
+        </pluginRepository>
+        <pluginRepository>
+            <id>spring-milestones</id>
+            <name>Spring Milestones</name>
+            <url>https://repo.spring.io/milestone</url>
+        </pluginRepository>
+    </pluginRepositories>
+</project>

spring-boot-mvc-2/src/main/java/com/baeldung/springbootmvc/SpringBootMvcFnApplication.java

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+package com.baeldung.springbootmvc;
+
+import static org.springframework.web.servlet.function.RouterFunctions.route;
+import static org.springframework.web.servlet.function.ServerResponse.notFound;
+import static org.springframework.web.servlet.function.ServerResponse.status;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.servlet.function.RequestPredicates;
+import org.springframework.web.servlet.function.RouterFunction;
+import org.springframework.web.servlet.function.ServerResponse;
+
+import com.baeldung.springbootmvc.ctrl.ProductController;
+import com.baeldung.springbootmvc.svc.ProductService;
+
+@SpringBootApplication
+public class SpringBootMvcFnApplication {
+
+    private static final Logger LOG = LoggerFactory.getLogger(SpringBootMvcFnApplication.class);
+
+    public static void main(String[] args) {
+        SpringApplication.run(SpringBootMvcFnApplication.class, args);
+    }
+
+    @Bean
+    RouterFunction<ServerResponse> productListing(ProductController pc, ProductService ps) {
+        return pc.productListing(ps);
+    }
+
+    @Bean
+    RouterFunction<ServerResponse> allApplicationRoutes(ProductController pc, ProductService ps) {
+        return route().add(pc.remainingProductRoutes(ps))
+            .before(req -> {
+                LOG.info("Found a route which matches " + req.uri()
+                    .getPath());
+                return req;
+            })
+            .after((req, res) -> {
+                if (res.statusCode() == HttpStatus.OK) {
+                    LOG.info("Finished processing request " + req.uri()
+                        .getPath());
+                } else {
+                    LOG.info("There was an error while processing request" + req.uri());
+                }
+                return res;
+            })
+            .onError(Throwable.class, (e, res) -> {
+                LOG.error("Fatal exception has occurred", e);
+                return status(HttpStatus.INTERNAL_SERVER_ERROR).build();
+            })
+            .build()
+            .and(route(RequestPredicates.all(), req -> notFound().build()));
+    }
+
+    public static class Error {
+        private String errorMessage;
+
+        public Error(String message) {
+            this.errorMessage = message;
+        }
+
+        public String getErrorMessage() {
+            return errorMessage;
+        }
+
+        public void setErrorMessage(String errorMessage) {
+            this.errorMessage = errorMessage;
+        }
+    }
+}

spring-boot-mvc-2/src/main/java/com/baeldung/springbootmvc/ctrl/ProductController.java

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+package com.baeldung.springbootmvc.ctrl;
+
+import static org.springframework.web.servlet.function.RouterFunctions.route;
+import static org.springframework.web.servlet.function.ServerResponse.ok;
+import static org.springframework.web.servlet.function.ServerResponse.status;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.function.EntityResponse;
+import org.springframework.web.servlet.function.RequestPredicates;
+import org.springframework.web.servlet.function.RouterFunction;
+import org.springframework.web.servlet.function.ServerRequest;
+import org.springframework.web.servlet.function.ServerResponse;
+
+import com.baeldung.springbootmvc.SpringBootMvcFnApplication.Error;
+import com.baeldung.springbootmvc.model.Product;
+import com.baeldung.springbootmvc.svc.ProductService;
+
+@Component
+public class ProductController {
+
+    public RouterFunction<ServerResponse> productListing(ProductService ps) {
+        return route().GET("/product", req -> ok().body(ps.findAll()))
+            .build();
+    }
+
+    public RouterFunction<ServerResponse> productSearch(ProductService ps) {
+        return route().nest(RequestPredicates.path("/product"), builder -> {
+            builder.GET("/name/{name}", req -> ok().body(ps.findByName(req.pathVariable("name"))))
+                .GET("/id/{id}", req -> ok().body(ps.findById(Integer.parseInt(req.pathVariable("id")))));
+        })
+            .onError(ProductService.ItemNotFoundException.class, (e, req) -> EntityResponse.fromObject(new Error(e.getMessage()))
+                .status(HttpStatus.NOT_FOUND)
+                .build())
+            .build();
+    }
+
+    public RouterFunction<ServerResponse> adminFunctions(ProductService ps) {
+        return route().POST("/product", req -> ok().body(ps.save(req.body(Product.class))))
+            .filter((req, next) -> authenticate(req) ? next.handle(req) : status(HttpStatus.UNAUTHORIZED).build())
+            .onError(IllegalArgumentException.class, (e, req) -> EntityResponse.fromObject(new Error(e.getMessage()))
+                .status(HttpStatus.BAD_REQUEST)
+                .build())
+            .build();
+    }
+
+    public RouterFunction<ServerResponse> remainingProductRoutes(ProductService ps) {
+        return route().add(productSearch(ps))
+            .add(adminFunctions(ps))
+            .build();
+    }
+
+    private boolean authenticate(ServerRequest req) {
+        return Boolean.TRUE;
+    }
+
+}

spring-boot-mvc-2/src/main/java/com/baeldung/springbootmvc/model/Product.java

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+package com.baeldung.springbootmvc.model;
+
+public class Product {
+    private String name;
+    private double price;
+    private int id;
+
+    public Product(String name, double price, int id) {
+        super();
+        this.name = name;
+        this.price = price;
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public void setPrice(double price) {
+        this.price = price;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + id;
+        result = prime * result + ((name == null) ? 0 : name.hashCode());
+        long temp;
+        temp = Double.doubleToLongBits(price);
+        result = prime * result + (int) (temp ^ (temp >>> 32));
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        Product other = (Product) obj;
+        if (id != other.id)
+            return false;
+        if (name == null) {
+            if (other.name != null)
+                return false;
+        } else if (!name.equals(other.name))
+            return false;
+        if (Double.doubleToLongBits(price) != Double.doubleToLongBits(other.price))
+            return false;
+        return true;
+    }
+
+}

spring-boot-mvc-2/src/main/java/com/baeldung/springbootmvc/svc/ProductService.java

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+package com.baeldung.springbootmvc.svc;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.springframework.stereotype.Service;
+import org.springframework.util.StringUtils;
+
+import com.baeldung.springbootmvc.model.Product;
+
+@Service
+public class ProductService {
+
+    private final Set<Product> products = new HashSet<>();
+
+    {
+        products.add(new Product("Book", 23.90, 1));
+        products.add(new Product("Pen", 44.34, 2));
+    }
+
+    public Product findById(int id) {
+        return products.stream()
+            .filter(obj -> obj.getId() == id)
+            .findFirst()
+            .orElseThrow(() -> new ItemNotFoundException("Product not found"));
+    }
+
+    public Product findByName(String name) {
+        return products.stream()
+            .filter(obj -> obj.getName()
+                .equalsIgnoreCase(name))
+            .findFirst()
+            .orElseThrow(() -> new ItemNotFoundException("Product not found"));
+    }
+
+    public Set<Product> findAll() {
+        return products;
+    }
+
+    public Product save(Product product) {
+        if (StringUtils.isEmpty(product.getName()) || product.getPrice() == 0.0) {
+            throw new IllegalArgumentException();
+        }
+        int newId = products.stream()
+            .mapToInt(Product::getId)
+            .max()
+            .getAsInt() + 1;
+        product.setId(newId);
+        products.add(product);
+        return product;
+    }
+
+    public static class ItemNotFoundException extends RuntimeException {
+        /**
+         * 
+         */
+        private static final long serialVersionUID = 1L;
+
+        public ItemNotFoundException(String msg) {
+            super(msg);
+        }
+    }
+}

spring-boot-mvc-2/src/main/resources/application.properties

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+spring.main.allow-bean-definition-overriding=true

spring-boot-mvc-2/src/main/resources/logback.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>