Merge branch 'eugenp:master' into master

parent-boot-3/README.md

@@ -0,0 +1,3 @@
+## Parent Boot 2
+
+This is a parent module for all projects using Spring Boot 3.

parent-boot-3/pom.xml

@@ -0,0 +1,97 @@
+<?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>parent-boot-3</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>parent-boot-3</name>
+    <packaging>pom</packaging>
+    <description>Parent for all Spring Boot 3 modules</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.junit</groupId>
+                <artifactId>junit-bom</artifactId>
+                <version>${junit-jupiter.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-dependencies</artifactId>
+                <version>${spring-boot.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.springframework.boot</groupId>
+                    <artifactId>spring-boot-maven-plugin</artifactId>
+                    <version>${spring-boot.version}</version>
+                    <configuration>
+                        <mainClass>${start-class}</mainClass>
+                        <!-- this is necessary as we're not using the Boot parent -->
+                    </configuration>
+                    <executions>
+                        <execution>
+                            <goals>
+                                <goal>repackage</goal>
+                            </goals>
+                        </execution>
+                    </executions>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+    <repositories>
+        <repository>
+            <id>spring-milestones</id>
+            <name>Spring Milestones</name>
+            <url>https://repo.spring.io/milestone</url>
+            <snapshots>
+                <enabled>false</enabled>
+            </snapshots>
+        </repository>
+    </repositories>
+    <pluginRepositories>
+        <pluginRepository>
+            <id>spring-milestones</id>
+            <name>Spring Milestones</name>
+            <url>https://repo.spring.io/milestone</url>
+            <snapshots>
+                <enabled>false</enabled>
+            </snapshots>
+        </pluginRepository>
+    </pluginRepositories>
+
+    <properties>
+        <spring-boot.version>3.0.0-M3</spring-boot.version>
+        <junit-jupiter.version>5.8.2</junit-jupiter.version>
+        <maven-surefire-plugin.version>3.0.0-M7</maven-surefire-plugin.version>
+        <lombok.version>1.18.22</lombok.version>
+        <java.version>17</java.version>
+        <maven-pmd-plugin.version>3.17.0</maven-pmd-plugin.version>
+    </properties>
+
+</project>

pom.xml

@@ -1252,6 +1252,7 @@
                  <module>quarkus-modules/quarkus-jandex</module>
                  <module>spring-boot-modules/spring-boot-cassandre</module>
                  <module>spring-boot-modules/spring-boot-camel</module>
+                 <module>spring-boot-modules/spring-boot-3</module>
                  <module>testing-modules/testing-assertions</module>
                  <module>persistence-modules/fauna</module>
                  <module>lightrun</module>

spring-boot-modules/spring-boot-3/pom.xml

@@ -0,0 +1,128 @@
+<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-boot-3</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-3</relativePath>
+    </parent>
+    <artifactId>spring-boot-3-sample</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>spring-boot-3-sample</name>
+    <description>Demo project for Spring Boot</description>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-hateoas</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <!-- Treiber: nicht gegen diese API programmieren, erst zur Laufzeit benötigt -->
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-devtools</artifactId>
+            <scope>runtime</scope>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-configuration-processor</artifactId>
+            <optional>true</optional>
+        </dependency>
+        <!-- depends on javax.servlet, see https://github.com/springdoc/springdoc-openapi/issues/1284
+        <dependency>
+            <groupId>org.springdoc</groupId>
+            <artifactId>springdoc-openapi-ui</artifactId>
+            <version>1.6.9</version>
+        </dependency>
+        -->
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>org.mapstruct</groupId>
+            <artifactId>mapstruct</artifactId>
+            <version>${mapstruct.version}</version>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <configuration>
+                        <annotationProcessorPaths>
+                            <path>
+                                <groupId>org.mapstruct</groupId>
+                                <artifactId>mapstruct-processor</artifactId>
+                                <version>${mapstruct.version}</version>
+                            </path>
+                            <path>
+                                <groupId>org.projectlombok</groupId>
+                                <artifactId>lombok</artifactId>
+                                <version>${lombok.version}</version>
+                            </path>
+                            <!-- This is needed when using Lombok 1.18.16 and above -->
+                            <path>
+                                <groupId>org.projectlombok</groupId>
+                                <artifactId>lombok-mapstruct-binding</artifactId>
+                                <version>0.2.0</version>
+                            </path>
+                        </annotationProcessorPaths>
+                    </configuration>
+                </plugin>
+                <plugin>
+                    <groupId>org.springframework.boot</groupId>
+                    <artifactId>spring-boot-maven-plugin</artifactId>
+                    <configuration>
+                        <excludes>
+                            <exclude>
+                                <groupId>org.projectlombok</groupId>
+                                <artifactId>lombok</artifactId>
+                            </exclude>
+                        </excludes>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <mapstruct.version>1.5.2.Final</mapstruct.version>
+        <start-class>com.baeldung.sample.TodoApplication</start-class>
+    </properties>
+
+</project>

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/TodoApplication.java

@@ -0,0 +1,11 @@
+package com.baeldung.sample;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+@SpringBootApplication
+public class TodoApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(TodoApplication.class, args);
+    }
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/boundary/CorsConfiguration.java

@@ -0,0 +1,42 @@
+package com.baeldung.sample.boundary;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.servlet.config.annotation.CorsRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+import static java.util.Arrays.stream;
+import static org.springframework.http.HttpHeaders.ACCEPT;
+import static org.springframework.http.HttpHeaders.ACCEPT_LANGUAGE;
+import static org.springframework.http.HttpHeaders.CONTENT_LANGUAGE;
+import static org.springframework.http.HttpHeaders.CONTENT_TYPE;
+import static org.springframework.http.HttpHeaders.IF_MATCH;
+import static org.springframework.http.HttpHeaders.IF_NONE_MATCH;
+import static org.springframework.http.HttpHeaders.LINK;
+import static org.springframework.http.HttpHeaders.LOCATION;
+import static org.springframework.http.HttpHeaders.ORIGIN;
+
+@Configuration
+public class CorsConfiguration {
+
+    @Bean
+    public WebMvcConfigurer corsConfigurer(final CorsConfigurationData allowed) {
+        return new WebMvcConfigurer() {
+
+            @Override
+            public void addCorsMappings(final CorsRegistry registry) {
+                registry.addMapping("/**")
+                  .exposedHeaders(LOCATION, LINK)
+                  // allow all HTTP request methods
+                  .allowedMethods(stream(RequestMethod.values()).map(Enum::name).toArray(String[]::new)) //
+                  // allow the commonly used headers
+                  .allowedHeaders(ORIGIN, CONTENT_TYPE, CONTENT_LANGUAGE, ACCEPT, ACCEPT_LANGUAGE, IF_MATCH, IF_NONE_MATCH) //
+                  // this is stage specific
+                  .allowedOrigins(allowed.getOrigins())
+                  .allowCredentials(allowed.isCredentials());
+            }
+        };
+    }
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/boundary/CorsConfigurationData.java

@@ -0,0 +1,25 @@
+package com.baeldung.sample.boundary;
+
+import lombok.Data;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * The properties from application.yml. You can specify them by the following snippet:
+ *
+ * <pre>
+ * server:
+ *   endpoints:
+ *     api:
+ *       v1: /api/v1
+ * </pre>
+ */
+@Configuration
+@ConfigurationProperties(prefix = "cors.allow")
+@Data
+public class CorsConfigurationData {
+
+    private String[] origins = { "*" };
+    private boolean credentials = false;
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/boundary/GlobalExceptionHandler.java

@@ -0,0 +1,22 @@
+package com.baeldung.sample.boundary;
+
+import com.baeldung.sample.control.NotFoundException;
+import jakarta.validation.ValidationException;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(NotFoundException.class)
+    @ResponseStatus(HttpStatus.NOT_FOUND)
+    protected void handleNotFoundException() {}
+
+    @ExceptionHandler({ValidationException.class, MethodArgumentNotValidException.class})
+    @ResponseStatus(HttpStatus.UNPROCESSABLE_ENTITY)
+    protected void handleValidationException() {}
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/boundary/TodoDtoMapper.java

@@ -0,0 +1,36 @@
+package com.baeldung.sample.boundary;
+
+import com.baeldung.sample.control.Todo;
+import org.mapstruct.Mapper;
+
+import java.util.Locale;
+
+/**
+ * Dieser Mapper kopiert die Informationen zwischen den Schichten.
+ */
+@Mapper(componentModel = "spring")
+interface TodoDtoMapper {
+
+    TodoResponseDto map(Todo todo);
+
+    default String _mapStatus(Todo.Status status) {
+        return switch (status) {
+            case NEW -> "new";
+            case PROGRESS -> "progress";
+            case COMPLETED -> "completed";
+            case ARCHIVED -> "archived";
+        };
+    }
+
+    Todo map(TodoRequestDto todo, Long id);
+
+    default Todo.Status _mapStatus(String status) {
+        return null == status ? Todo.Status.NEW : switch (status) {
+            case "progress" -> Todo.Status.PROGRESS;
+            case "completed" -> Todo.Status.COMPLETED;
+            case "archived" -> Todo.Status.ARCHIVED;
+            default -> Todo.Status.NEW;
+        };
+    }
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/boundary/TodoRequestDto.java

@@ -0,0 +1,17 @@
+package com.baeldung.sample.boundary;
+
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.Pattern;
+import lombok.Data;
+
+import java.time.LocalDate;
+
+@Data
+public class TodoRequestDto {
+    @NotBlank
+    private String title;
+    private String description;
+    private LocalDate dueDate;
+    @Pattern(regexp = "new|progress|completed|archived")
+    private String status;
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/boundary/TodoResponseDto.java

@@ -0,0 +1,15 @@
+package com.baeldung.sample.boundary;
+
+import lombok.Data;
+
+import java.time.LocalDate;
+
+@Data
+public class TodoResponseDto {
+    private Long id;
+    private String title;
+    private String description;
+    private LocalDate dueDate;
+    private String status;
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/boundary/TodosController.java

@@ -0,0 +1,83 @@
+package com.baeldung.sample.boundary;
+
+import com.baeldung.sample.control.NotFoundException;
+import com.baeldung.sample.control.TodosService;
+import jakarta.validation.Valid;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+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.PostMapping;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.net.URI;
+import java.util.Collection;
+import java.util.stream.Collectors;
+
+import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.linkTo;
+import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.methodOn;
+import static org.springframework.http.HttpStatus.NO_CONTENT;
+
+@RestController
+@RequestMapping("/api/v1/todos")
+@RequiredArgsConstructor
+public class TodosController {
+
+    private static final String DEFAULT_MEDIA_TYPE = MediaType.APPLICATION_JSON_VALUE;
+
+    private final TodosService service;
+    // Mapping zwischen den Schichten
+    private final TodoDtoMapper mapper;
+
+    @GetMapping(produces = DEFAULT_MEDIA_TYPE)
+    public Collection<TodoResponseDto> findAll() {
+        return service.findAll().stream()
+          .map(mapper::map)
+          .collect(Collectors.toList());
+    }
+
+    @GetMapping(value = "/{id}", produces = DEFAULT_MEDIA_TYPE)
+    public TodoResponseDto findById(
+      @PathVariable("id") final Long id
+    ) {
+        // Action
+        return service.findById(id) //
+          .map(mapper::map) // map to dto
+          .orElseThrow(NotFoundException::new);
+    }
+
+    @PostMapping(consumes = DEFAULT_MEDIA_TYPE)
+    public ResponseEntity<TodoResponseDto> create(final @Valid @RequestBody TodoRequestDto item) {
+        // Action
+        final var todo = mapper.map(item, null);
+        final var newTodo = service.create(todo);
+        final var result = mapper.map(newTodo);
+        // Response
+        final URI locationHeader = linkTo(methodOn(TodosController.class).findById(result.getId())).toUri(); // HATEOAS
+        return ResponseEntity.created(locationHeader).body(result);
+    }
+
+    @PutMapping(value = "{id}", consumes = DEFAULT_MEDIA_TYPE)
+    @ResponseStatus(NO_CONTENT)
+    public void update(
+      @PathVariable("id") final Long id,
+      @Valid @RequestBody final TodoRequestDto item
+    ) {
+        service.update(mapper.map(item, id));
+    }
+
+    @DeleteMapping("/{id}")
+    @ResponseStatus(NO_CONTENT)
+    public void delete(
+      @PathVariable("id") final Long id
+    ) {
+        service.delete(id);
+    }
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/control/DataInitializationConfigurationData.java

@@ -0,0 +1,14 @@
+package com.baeldung.sample.control;
+
+import lombok.Data;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@ConfigurationProperties(prefix = "application.data")
+@Data
+public class DataInitializationConfigurationData {
+
+    private boolean initializeOnStartup = true;
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/control/NotFoundException.java

@@ -0,0 +1,5 @@
+package com.baeldung.sample.control;
+
+public class NotFoundException extends RuntimeException {
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/control/Todo.java

@@ -0,0 +1,24 @@
+package com.baeldung.sample.control;
+
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
+
+import java.time.LocalDate;
+
+public record Todo(
+  Long id,
+  @NotNull @Size(min = 1) String title,
+  String description,
+  LocalDate dueDate,
+  @NotNull Status status
+) {
+
+    public enum Status {
+        NEW, PROGRESS, COMPLETED, ARCHIVED
+    }
+
+    public Todo(Long id, String title) {
+        this(id, title, null, null, Status.NEW);
+    }
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/control/TodoEntityMapper.java

@@ -0,0 +1,16 @@
+package com.baeldung.sample.control;
+
+import com.baeldung.sample.entity.TodoEntity;
+import org.mapstruct.Mapper;
+
+/**
+ * Dieser Mapper kopiert die Informationen zwischen den Schichten.
+ */
+@Mapper(componentModel = "spring")
+interface TodoEntityMapper {
+
+    TodoEntity map(Todo todo);
+
+    Todo map(TodoEntity todo);
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/control/TodosInitializer.java

@@ -0,0 +1,28 @@
+package com.baeldung.sample.control;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.context.event.ContextRefreshedEvent;
+import org.springframework.context.event.EventListener;
+import org.springframework.stereotype.Component;
+
+@Component
+@RequiredArgsConstructor
+public class TodosInitializer {
+
+    private final TodosService service;
+    /*
+     * we cannot use @Profile("default") because
+     * we are not able inject the bean during test
+     * depending from the profile activation
+     */
+    private final DataInitializationConfigurationData config;
+
+    @EventListener(ContextRefreshedEvent.class)
+    public void initializeTodos() {
+        if (this.config.isInitializeOnStartup() && this.service.count() < 1) {
+            this.service.create(new Todo(null, "Deploy and run the application."));
+            this.service.create(new Todo(null, "Enter some TODO items!"));
+        }
+    }
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/control/TodosService.java

@@ -0,0 +1,103 @@
+package com.baeldung.sample.control;
+
+import com.baeldung.sample.entity.TodosRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.Collection;
+import java.util.Optional;
+
+import static java.util.stream.Collectors.toList;
+
+/**
+ * Ein Service ist ein Singleton auf Control Layer, der in der Boundary von mehreren (REST) Controllern gemeinsam genutzt werden kann.
+ * Dieser hat keinen Bezug mehr zu HTTP.
+ */
+@Service
+@RequiredArgsConstructor
+public class TodosService {
+
+    private final TodoEntityMapper mapper;
+    private final TodosRepository repo;
+
+    /**
+     * Gibt die Anzahl an Datensätzen zurück.
+     * @return die Anzahl an Datensätzen
+     */
+    long count() {
+        return repo.count();
+    }
+
+    /**
+     * Gibt alle Todos zurück.
+     *
+     * @return eine unveränderliche Collection
+     */
+    public Collection<Todo> findAll() {
+        return repo.findAll().stream()
+          .map(mapper::map)
+          .collect(toList());
+    }
+
+    /**
+     * Durchsucht die Todos nach einer ID.
+     *
+     * @param id die ID
+     * @return das Suchergebnis
+     */
+    public Optional<Todo> findById(long id) {
+        return repo.findById(id)
+          .map(mapper::map);
+    }
+
+    /**
+     * Fügt ein Item in den Datenbestand hinzu. Dabei wird eine ID generiert.
+     *
+     * @param item das anzulegende Item (ohne ID)
+     * @return das gespeicherte Item (mit ID)
+     * @throws IllegalArgumentException wenn das Item null oder die ID bereits belegt ist
+     */
+    public Todo create(Todo item) {
+        if (null == item || null != item.id()) {
+            throw new IllegalArgumentException("item must exist without any id");
+        }
+        return mapper.map(repo.save(mapper.map(item)));
+    }
+
+    /**
+     * Aktualisiert ein Item im Datenbestand.
+     *
+     * @param item das zu ändernde Item mit ID
+     * @throws IllegalArgumentException
+     * wenn das Item oder dessen ID nicht belegt ist
+     * @throws NotFoundException
+     * wenn das Element mit der ID nicht gefunden wird
+     */
+    public void update(Todo item) {
+        if (null == item || null == item.id()) {
+            throw new IllegalArgumentException("item must exist with an id");
+        }
+        // remove separat, um nicht neue Einträge hinzuzufügen (put allein würde auch ersetzen)
+        if (repo.existsById(item.id())) {
+            repo.save(mapper.map(item));
+        } else {
+            throw new NotFoundException();
+        }
+    }
+
+    /**
+     * Entfernt ein Item aus dem Datenbestand.
+     *
+     * @param id die ID des zu löschenden Items
+     * @throws NotFoundException
+     * wenn das Element mit der ID nicht gefunden wird
+     */
+    public void delete(long id) {
+        if (repo.existsById(id)) {
+            repo.deleteById(id);
+        } else {
+            throw new NotFoundException();
+        }
+    }
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/entity/TodoEntity.java

@@ -0,0 +1,53 @@
+package com.baeldung.sample.entity;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Enumerated;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import lombok.ToString;
+
+import java.time.LocalDate;
+
+/*
+ * Auch hier wird eine separate Klasse erstellt.
+ * Und auch hier geht es wieder um Unabhängigkeit der beiden Layer (Control und Persistence).
+ * So kann z.B. die Auflösung von Fremdschlüsseln (assignee, priority, topic) in der Persistence Layer erfolgen (JPA unterstützt das), oder aber auch erst in der Control Layer.
+ */
+@Entity(name = "todo")
+@Table(name = "todos")
+// we do not use @Data because hashCode() and equals() might influence JPA's behaviour
+@NoArgsConstructor
+@Getter
+@Setter
+@ToString
+public class TodoEntity {
+
+    public enum StatusEntity {
+        NEW, PROGRESS, COMPLETED, ARCHIVED
+    }
+
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    @Id
+    private Long id;
+    @NotNull
+    @Size(min = 1)
+    private String title;
+    private String description;
+    private LocalDate dueDate;
+    @Enumerated
+    @NotNull
+    private StatusEntity status = StatusEntity.NEW;
+
+    public TodoEntity(Long id, String title) {
+        this.id = id;
+        this.title = title;
+    }
+
+}

spring-boot-modules/spring-boot-3/src/main/java/com/baeldung/sample/entity/TodosRepository.java

@@ -0,0 +1,9 @@
+package com.baeldung.sample.entity;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface TodosRepository extends JpaRepository<TodoEntity, Long> {
+
+}

spring-boot-modules/spring-boot-3/src/main/resources/application.yml

@@ -0,0 +1,21 @@
+spring:
+  mvc:
+    throw-exception-if-no-handler-found: true
+  jackson:
+    deserialization:
+      FAIL_ON_UNKNOWN_PROPERTIES: true
+    property-naming-strategy: SNAKE_CASE
+  jpa:
+    open-in-view: false
+    generate-ddl: true
+    show-sql: true
+    hibernate:
+      ddl-auto: update
+    properties:
+      hibernate:
+        dialect: org.hibernate.dialect.H2Dialect
+# Custom Properties
+cors:
+  allow:
+    origins: ${CORS_ALLOWED_ORIGINS:*}
+    credentials: ${CORS_ALLOW_CREDENTIALS:false}

spring-boot-modules/spring-boot-3/src/test/java/com/baeldung/sample/boundary/TodosBoundaryLayer.java

@@ -0,0 +1,13 @@
+package com.baeldung.sample.boundary;
+
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.ComponentScan;
+
+/**
+ * This class bundles all classes in the boundary layer.
+ * This includes also the generated mapper classes.
+ */
+@TestConfiguration
+@ComponentScan(basePackageClasses = TodosBoundaryLayer.class)
+public class TodosBoundaryLayer {
+}

spring-boot-modules/spring-boot-3/src/test/java/com/baeldung/sample/boundary/TodosControllerApiIntegrationTest.java

@@ -0,0 +1,218 @@
+package com.baeldung.sample.boundary;
+
+import com.baeldung.sample.control.NotFoundException;
+import com.baeldung.sample.control.Todo;
+import com.baeldung.sample.control.TodosService;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.web.servlet.MockMvc;
+
+import java.util.List;
+import java.util.Optional;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.when;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.delete;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.put;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.header;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+/**
+ * Integrationstests der Todos REST API auf HTTP Layer. Die Anwendung wird als Black Box behandelt.
+ * Somit müssen alle Tests, die einen existierenden Datensatz benötigen, diesen im Test anlegen.
+ * Spring Boot startet den sog. "ApplicationContext" automatisch und bietet Möglichkeiten, die Anwendungsteile vom Test aus aufzurufen.
+ */
+@WebMvcTest
+@ContextConfiguration(classes = TodosBoundaryLayer.class)
+class TodosControllerApiIntegrationTest {
+
+    private static final String BASEURL = "/api/v1/todos"; // URL to Resource
+    private static final String DEFAULT_MEDIA_TYPE = MediaType.APPLICATION_JSON_VALUE;
+
+    @MockBean
+    TodosService service;
+    @Autowired
+    MockMvc mvc; // testing by sending HTTP requests and verifying HTTP responses
+    @Autowired
+    ObjectMapper mapper; // used to render or parse JSON
+
+    /*
+     * Testfall:
+     *  - GET auf alle Todos -> 200 OK mit JSON
+     */
+    @DisplayName("GET auf alle Daten (200 OK)")
+    @Test
+    void testFindAllTodos() throws Exception {
+        when(service.findAll()).thenReturn(List.of());
+        mvc
+          .perform(get(BASEURL).accept(DEFAULT_MEDIA_TYPE))
+          .andExpect(status().isOk())
+          .andExpect(content().contentType(DEFAULT_MEDIA_TYPE));
+    }
+
+    /*
+     * Testfall:
+     *  - einzelnes Todos auslesen -> kein Fehler
+     */
+    @Test
+    void testFindById() throws Exception {
+        when(service.findById(1L))
+          .thenReturn(Optional.of(new Todo(1L, "test")));
+        mvc
+          .perform(get(BASEURL + "/1").accept(DEFAULT_MEDIA_TYPE))
+          .andExpect(status().isOk())
+          .andExpect(content().contentType(DEFAULT_MEDIA_TYPE))
+          .andExpect(jsonPath("$.title").value("test"));
+    }
+
+    /*
+     * Testfall:
+     *  - einzelnes Todos auslesen -> 404
+     */
+    @Test
+    void testFindByIdNotExisting() throws Exception {
+        when(service.findById(1L))
+          .thenReturn(Optional.empty());
+        mvc
+          .perform(get(BASEURL + "/1").accept(DEFAULT_MEDIA_TYPE))
+          .andExpect(status().isNotFound());
+    }
+
+    /*
+     * Testfall:
+     *  - Anlegen eines Todos per POST -> 201 mit Location Header
+     */
+    @DisplayName("POST liefert 201 mit Location-Header")
+    @Test
+    void testCreateTodo() throws Exception {
+        // etwas umständlich, die ID zu besetzen, wenn auf dem Service create() aufgerufen wird
+        when(service.create(any())).thenReturn(new Todo(5L, "test-todo"));
+        final var json = "{\"title\":\"test-todo\"}";
+        mvc
+          .perform(post(BASEURL).contentType(DEFAULT_MEDIA_TYPE).content(json))
+          .andExpect(status().isCreated())
+          .andExpect(header().exists(HttpHeaders.LOCATION))
+          .andExpect(jsonPath("$.id").value(5L));
+    }
+
+    /*
+     * Testfall:
+     *  - Anlegen eines Todos per POST ohne Titel -> 422
+     */
+    @DisplayName("POST erzeugt kein Todo, wenn kein Titel angegeben ist")
+    @Test
+    void testCreateTodoWithoutTitle() throws Exception {
+        final var json = "{}";
+        mvc
+          .perform(post(BASEURL).contentType(DEFAULT_MEDIA_TYPE).content(json))
+          .andExpect(status().isUnprocessableEntity());
+        verifyNoInteractions(service);
+    }
+
+    /*
+     * Testfall:
+     *  - Anlegen eines Todos per POST mit ID -> 400
+     */
+    @DisplayName("POST erzeugt kein Todo, wenn die ID mitgegeben wird (undefinierte Property)")
+    @Test
+    void testCreateTodoWithID() throws Exception {
+        final var json = "{\"id\":1, \"title\":\"test\"}";
+        mvc
+          .perform(post(BASEURL).contentType(DEFAULT_MEDIA_TYPE).content(json))
+          .andExpect(status().isBadRequest());
+        verifyNoInteractions(service);
+    }
+
+    /*
+     * Testfall:
+     *  - Anlegen eines Todos per POST mit leerem Titel -> 400
+     */
+    @DisplayName("POST erzeugt kein Todo, wenn Titel weniger als 1 Zeichen hat")
+    @Test
+    void testCreateTodoWithEmptyTitle() throws Exception {
+        final var newTodo = new TodoRequestDto();
+        newTodo.setTitle("");
+        final String json = mapper.writeValueAsString(newTodo);
+        this.mvc //
+          .perform(post(BASEURL).contentType(DEFAULT_MEDIA_TYPE).content(json)) //
+          .andExpect(status().isUnprocessableEntity());
+    }
+
+    /*
+     * Testfall:
+     *  - Ändern -> 204
+     */
+    @Test
+    void testUpdateTodo() throws Exception {
+        final var json = "{\"title\":\"test-todo\"}";
+        mvc
+          .perform(put(BASEURL + "/5").contentType(DEFAULT_MEDIA_TYPE).content(json))
+          .andExpect(status().isNoContent());
+    }
+
+    /*
+     * Testfall:
+     *  - Ändern -> 404
+     */
+    @Test
+    void testUpdateTodoNotExisting() throws Exception {
+        doThrow(NotFoundException.class).when(service).update(any());
+        final var json = "{\"title\":\"test-todo\"}";
+        mvc
+          .perform(put(BASEURL + "/5").contentType(DEFAULT_MEDIA_TYPE).content(json))
+          .andExpect(status().isNotFound());
+    }
+
+    /*
+     * Testfall:
+     *  - Ändern des Todos mit leerem Titel
+     */
+    @Test
+    @DisplayName("PUT mit leerem Titel")
+    void testUpdateWithEmptyTitle() throws Exception {
+        // Act
+        final var json = "{}";
+        mvc
+          .perform(put(BASEURL + "/5").contentType(DEFAULT_MEDIA_TYPE).content(json))
+          .andExpect(status().isUnprocessableEntity());
+        verifyNoInteractions(service);
+    }
+
+    /*
+     * Testfall:
+     *  - Löschen -> 204
+     */
+    @Test
+    void testDeleteTodo() throws Exception {
+        mvc
+          .perform(delete(BASEURL + "/5").contentType(DEFAULT_MEDIA_TYPE))
+          .andExpect(status().isNoContent());
+    }
+
+    /*
+     * Testfall:
+     *  - Löschen -> 404
+     */
+    @Test
+    void testDeleteTodoNotExisting() throws Exception {
+        doThrow(NotFoundException.class).when(service).delete(anyLong());
+        mvc
+          .perform(delete(BASEURL + "/5").contentType(DEFAULT_MEDIA_TYPE))
+          .andExpect(status().isNotFound());
+    }
+
+}

spring-boot-modules/spring-boot-3/src/test/java/com/baeldung/sample/control/TodosControlLayer.java

@@ -0,0 +1,13 @@
+package com.baeldung.sample.control;
+
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.ComponentScan;
+
+/**
+ * This class bundles all classes in the control layer.
+ * This includes also the generated mapper classes.
+ */
+@TestConfiguration
+@ComponentScan(basePackageClasses = TodosControlLayer.class)
+public class TodosControlLayer {
+}

spring-boot-modules/spring-boot-3/src/test/java/com/baeldung/sample/control/TodosInitializerActivationIntegrationTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.sample.control;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.atLeastOnce;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+@SpringBootTest
+class TodosInitializerActivationIntegrationTest {
+
+    @MockBean
+    TodosService service;
+
+    @BeforeEach
+    void serviceHasEmptyData() {
+        when(service.count()).thenReturn(0L);
+    }
+
+    @AfterEach
+    void serviceHasNoFurtherInteractions() {
+        verifyNoMoreInteractions(service);
+    }
+
+    @Test
+    @DisplayName("data initialization is invoked on default profile")
+    void testIsInvoked() {
+        verify(service).count();
+        verify(service, atLeastOnce()).create(any());
+    }
+
+}

spring-boot-modules/spring-boot-3/src/test/java/com/baeldung/sample/control/TodosServiceDatabaseIntegrationTest.java

@@ -0,0 +1,63 @@
+package com.baeldung.sample.control;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.transaction.annotation.Transactional;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+@SpringBootTest
+@AutoConfigureTestDatabase
+@Transactional
+@TestPropertySource(
+  properties = {
+    "application.data.initialize-on-startup=false"
+  }
+)
+class TodosServiceDatabaseIntegrationTest {
+
+    @Autowired
+    TodosService service;
+
+    @BeforeEach
+    void assertEmpty() {
+        assertThat(service.count())
+          .isZero();
+    }
+
+    @Test
+    void testCreate() {
+        service.create(new Todo(null, "test"));
+        assertThat(service.count())
+          .isEqualTo(1);
+        assertThat(service.findAll())
+          .hasSize(1)
+          .element(0).extracting(Todo::title).isEqualTo("test");
+    }
+
+    @Test
+    void testFindById() {
+        final var todo = service.create(new Todo(null, "test"));
+        final var result = service.findById(todo.id());
+        assertThat(result)
+          .isNotEmpty()
+          .get().usingRecursiveComparison().isEqualTo(todo);
+    }
+
+    @Test
+    void testDelete() {
+        final var todo = service.create(new Todo(null, "test"));
+        final var id = todo.id();
+        service.delete(id);
+        final var result = service.findById(id);
+        assertThat(result).isEmpty();
+        assertThatThrownBy(() -> service.delete(id))
+          .isInstanceOf(NotFoundException.class);
+    }
+
+}

spring-boot-modules/spring-boot-3/src/test/java/com/baeldung/sample/control/TodosServiceIntegrationTest.java

@@ -0,0 +1,126 @@
+package com.baeldung.sample.control;
+
+import com.baeldung.sample.entity.TodoEntity;
+import com.baeldung.sample.entity.TodosRepository;
+import org.junit.jupiter.api.Test;
+import org.mockito.Answers;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.refEq;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+/**
+ * Integrationstests des TodosServices. Die Anwendung wird als Black Box behandelt.
+ * Somit müssen alle Tests, die einen existierenden Datensatz benötigen, diesen im Test anlegen.
+ */
+@SpringBootTest(classes = TodosControlLayer.class)
+class TodosServiceIntegrationTest {
+
+    // dieses Objekt wird als Mock instruiert
+    // Answers.RETURNS_MOCKS ist notwendig, da Methoden in Service-Init-Methode bereits aufgerufen werden
+    @MockBean(answer = Answers.RETURNS_MOCKS)
+    TodosRepository repo;
+
+    @Autowired
+    TodosService service;
+
+    /*
+     * Testfall:
+     *  - alle Todos auslesen -> kein Fehler
+     */
+    @Test
+    void testFindAllTodos() {
+        when(repo.findAll()).thenReturn(List.of(new TodoEntity(1L, "test")));
+        final var result = service.findAll();
+        assertThat(result).hasSize(1) //
+          .element(0).extracting(Todo::id, Todo::title).containsExactly(1L, "test");
+    }
+
+    /*
+     * Testfall:
+     *  - Anlegen eines Todos -> ID besetzt
+     *  - Auslesen -> gefunden mit entsprechenden Werten
+     */
+    @Test
+    @SuppressWarnings("ConstantConditions")
+    void testCreateTodo() {
+        final var newTodo = new Todo(null, "test-todo");
+        when(repo.save(any())).thenReturn(new TodoEntity(5L, "test-todo"));
+        // create
+        final var result = this.service.create(newTodo);
+        // find out id
+        assertThat(result).extracting(Todo::id).isEqualTo(5L);
+        verify(repo).save(refEq(new TodoEntity(null, "test-todo")));
+    }
+
+    /*
+     * Testfall:
+     *  - Ändern eines bestehenden Todos
+     *  - Aufruf der Repo-Methode und Rückgabewert prüfen
+     */
+    @Test
+    @SuppressWarnings("ConstantConditions")
+    void testUpdateExisting() {
+        final var todo = new Todo(5L, "test-todo");
+        when(repo.existsById(todo.id())).thenReturn(true);
+        // Test
+        this.service.update(todo);
+        // Assert
+        verify(repo).save(refEq(new TodoEntity(5L, "test-todo")));
+    }
+
+    /*
+     * Testfall:
+     *  - Ändern eines nicht existenten Todos
+     *  - Aufruf der Repo-Methode und Rückgabewert prüfen
+     */
+    @Test
+    void testUpdateNotExisting() {
+        final var todo = new Todo(5L, "test-todo");
+        when(repo.existsById(todo.id())).thenReturn(false);
+        // Test+Assert
+        assertThatThrownBy(() -> this.service.update(todo))
+          .isInstanceOf(NotFoundException.class);
+        verify(repo).existsById(todo.id());
+        verifyNoMoreInteractions(repo);
+    }
+
+    /*
+     * Testfall:
+     *  - Löschen eines existenten Todos
+     *  - Aufruf der Repo-Methode und Rückgabewert prüfen
+     */
+    @Test
+    void testDeleteExisting() {
+        when(repo.existsById(5L)).thenReturn(true);
+        // Test
+        this.service.delete(5L);
+        // Assert
+        verify(repo).deleteById(5L);
+    }
+
+    /*
+     * Testfall:
+     *  - Löschen eines nicht existenten Todos
+     *  - Aufruf der Repo-Methode und Rückgabewert prüfen
+     */
+    @Test
+    void testDeleteNotExisting() {
+        when(repo.existsById(5L)).thenReturn(false);
+        // Test+Assert
+        assertThatThrownBy(() -> this.service.delete(5L))
+          .isInstanceOf(NotFoundException.class);
+        verify(repo).existsById(5L);
+        verifyNoMoreInteractions(repo);
+    }
+
+}

spring-boot-modules/spring-boot-3/src/test/java/com/baeldung/sample/shared/EnableBeanValidation.java

@@ -0,0 +1,15 @@
+package com.baeldung.sample.shared;
+
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.validation.beanvalidation.MethodValidationPostProcessor;
+
+@TestConfiguration
+public class EnableBeanValidation {
+
+    @Bean
+    public MethodValidationPostProcessor validator() {
+        return new MethodValidationPostProcessor();
+    }
+
+}