Add spring-boot-api-versioning module demonstrating multiple API vers…

spring-boot-modules/spring-boot-api-versioning/.gitignore

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+# Maven build
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+release.properties
+
+# IDE files
+.idea/
+*.iml
+*.ipr
+*.iws
+.vscode/
+.project
+.classpath
+.settings/
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# Logs
+logs/
+*.log

spring-boot-modules/spring-boot-api-versioning/README.md

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+# spring-boot-api-versioning
+Demonstrating API versioning strategies in Spring Boot
+# API Versioning in Spring Boot
+
+[![Spring Boot](https://img.shields.io/badge/Spring%20Boot-3.3+-brightgreen)](https://spring.io/projects/spring-boot)  
+[![Java](https://img.shields.io/badge/Java-17+-blue)](https://openjdk.org/)  
+[![Build](https://img.shields.io/badge/Build-Maven-orange)](https://maven.apache.org/)  
+
+A demo project showcasing **different strategies for API versioning in Spring Boot**, including:
+
+- URI Versioning  
+- Request Parameter Versioning  
+- Header Versioning  
+- Content Negotiation (MIME Type)  
+- Native Spring Boot 4 Annotation Support  
+
+---
+
+## Project Setup
+
+Clone the repository:
+
+```bash
+git clone https://github.com/your-org/api-versioning-spring-boot
+cd api-versioning-spring-boot
+```
+
+Build and run:
+
+```bash
+./mvnw spring-boot:run
+```
+
+---
+
+## Usage Examples
+
+### 1. URI Versioning
+```bash
+curl http://localhost:8080/api/v1/users
+curl http://localhost:8080/api/v2/users
+```
+
+### 2. Request Parameter Versioning
+```bash
+curl http://localhost:8080/api/users?version=1
+curl http://localhost:8080/api/users?version=2
+```
+
+### 3. Header Versioning
+```bash
+curl -H "API-VERSION: 1" http://localhost:8080/api/users
+curl -H "API-VERSION: 2" http://localhost:8080/api/users
+```
+
+### 4. Content Negotiation
+```bash
+curl -H "Accept: application/vnd.company.v1+json" http://localhost:8080/api/users
+curl -H "Accept: application/vnd.company.v2+json" http://localhost:8080/api/users
+```
+
+### 5. Native Annotation Support (Spring Boot 4)
+```bash
+curl http://localhost:8080/api/users --header "API-VERSION: 1"
+curl http://localhost:8080/api/users --header "API-VERSION: 2"
+```
+
+---
+
+## Tutorial Reference
+
+This project accompanies the post:  
+**[API Versioning in Spring](#)**  
+- (link will be added once published)  
+---
+
+## Running Tests
+
+```bash
+./mvnw test
+```
+
+---
+
+## Best Practices
+
+- Version only when necessary  
+- Document changes clearly  
+- Deprecate gracefully  
+- Automate testing across versions  
+- Align with business needs  
+
+---
+
+## 📜 License
+
+This project is licensed under the MIT License.
+
+---

spring-boot-modules/spring-boot-api-versioning/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung.example</groupId>
+    <artifactId>spring-boot-api-versioning</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>spring-boot-api-versioning</name>
+    <description>API versioning strategies in Spring Boot</description>
+
+    <properties>
+        <java.version>17</java.version>
+        <spring.boot.version>3.3.4</spring.boot.version>
+    </properties>
+
+    <!-- Import the Spring Boot BOM -->
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-dependencies</artifactId>
+                <version>${spring.boot.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <dependencies>
+        <!-- Web starter -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <!-- Actuator starter (for /actuator/mappings etc.) -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-actuator</artifactId>
+        </dependency>
+
+        <!-- Test starter (JUnit 5, Spring Boot Test, Mockito, etc.) -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+ <build>
+    <plugins>
+        <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-compiler-plugin</artifactId>
+            <version>3.11.0</version>
+            <configuration>
+                <source>${java.version}</source>
+                <target>${java.version}</target>
+                <compilerArgs>
+                    <arg>-parameters</arg>
+                </compilerArgs>
+            </configuration>
+        </plugin>
+
+        <plugin>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-maven-plugin</artifactId>
+            <version>${spring.boot.version}</version>
+        </plugin>
+    </plugins>
+</build>
+</project>

spring-boot-modules/spring-boot-api-versioning/src/main/java/com/baeldung/example/apiversioning/ApiVersioningDemoApplication.java

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+package com.baeldung.example.apiversioning;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ApiVersioningDemoApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(ApiVersioningDemoApplication.class, args);
+    }
+}

spring-boot-modules/spring-boot-api-versioning/src/main/java/com/baeldung/example/apiversioning/controller/UserParamController.java

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+package com.baeldung.example.apiversioning.controller;
+
+import com.baeldung.example.apiversioning.model.UserV2;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.List;
+
+@RestController
+public class UserParamController {
+
+@GetMapping("/api/users")
+public Object getUsers(@RequestParam(name = "version", defaultValue = "1") String version) {
+    if ("1".equals(version)) {
+        return List.of("Alice", "Bob");
+    } else if ("2".equals(version)) {
+        return List.of(
+            new UserV2("Alice", "alice@example.com", 30),
+            new UserV2("Bob", "bob@example.com", 25)
+        );
+    } else {
+        return "Unsupported API version";
+    }
+}
+
+}

spring-boot-modules/spring-boot-api-versioning/src/main/java/com/baeldung/example/apiversioning/controller/header/UserHeaderController.java

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+// src/main/java/.../controller/header/UserHeaderController.java
+package com.baeldung.example.apiversioning.controller.header;
+
+import com.baeldung.example.apiversioning.model.UserV1;
+import com.baeldung.example.apiversioning.model.UserV2;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestHeader;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.List;
+
+@RestController
+public class UserHeaderController {
+
+    @GetMapping(value = "/api/users", headers = "X-API-VERSION=1")
+public List<UserV1> getUsersV1() {
+    return List.of(new UserV1("Alice"), new UserV1("Bob"));
+}
+
+@GetMapping(value = "/api/users", headers = "X-API-VERSION=2")
+public List<UserV2> getUsersV2() {
+    return List.of(
+        new UserV2("Alice", "alice@example.com", 30),
+        new UserV2("Bob", "bob@example.com", 25)
+    );
+}
+}

spring-boot-modules/spring-boot-api-versioning/src/main/java/com/baeldung/example/apiversioning/controller/mime/UserMimeController.java

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+// src/main/java/com/baeldung/example/apiversioning/controller/mime/UserMimeController.java
+package com.baeldung.example.apiversioning.controller.mime;
+
+import com.baeldung.example.apiversioning.model.UserV1;
+import com.baeldung.example.apiversioning.model.UserV2;
+import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.List;
+
+@RestController
+public class UserMimeController {
+
+    public static final String V1_MEDIA = "application/vnd.example.users-v1+json";
+    public static final String V2_MEDIA = "application/vnd.example.users-v2+json";
+
+    @GetMapping(value = "/api/users", produces = V1_MEDIA)
+    public List<UserV1> usersV1() {
+        return List.of(new UserV1("Alice"), new UserV1("Bob"));
+    }
+
+    @GetMapping(value = "/api/users", produces = V2_MEDIA)
+    public List<UserV2> usersV2() {
+        return List.of(
+            new UserV2("Alice", "alice@example.com", 30),
+            new UserV2("Bob", "bob@example.com", 25)
+        );
+    }
+
+    // Optional fallback
+    @GetMapping(value = "/api/users", produces = MediaType.APPLICATION_JSON_VALUE)
+    public List<UserV1> defaultUsers() {
+        return List.of(new UserV1("Alice"), new UserV1("Bob"));
+    }
+}

spring-boot-modules/spring-boot-api-versioning/src/main/java/com/baeldung/example/apiversioning/controller/negotiation/UserContentNegotiationController.java

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+package com.baeldung.example.apiversioning.controller.negotiation;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/api/users")
+public class UserContentNegotiationController {
+
+    @GetMapping(value = "/negotiation", produces = "application/vnd.col.users.v1+json")
+    public String getUsersV1() {
+        return "User list v1";
+    }
+
+    @GetMapping(value = "/negotiation", produces = "application/vnd.col.users.v2+json")
+    public String getUsersV2() {
+        return "User list v2";
+    }
+}

spring-boot-modules/spring-boot-api-versioning/src/main/java/com/baeldung/example/apiversioning/controller/v1/UserV1Controller.java

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+package com.baeldung.example.apiversioning.controller.v1;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/api/v1/users")
+public class UserV1Controller {
+    @GetMapping
+    public String getUsersV1() {
+        return "User list from API v1";
+    }
+}

spring-boot-modules/spring-boot-api-versioning/src/main/java/com/baeldung/example/apiversioning/controller/v2/UserV2Controller.java

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+package com.baeldung.example.apiversioning.controller.v2;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/api/v2/users")
+public class UserV2Controller {
+    @GetMapping
+    public String getUsersV2() {
+        return "User list from API v2 with extra fields";
+    }
+}

spring-boot-modules/spring-boot-api-versioning/src/main/java/com/baeldung/example/apiversioning/model/UserV1.java

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+package com.baeldung.example.apiversioning.model;
+
+public class UserV1 {
+    private String name;
+    public UserV1() {}
+    public UserV1(String name) { this.name = name; }
+    public String getName() { return name; }
+    public void setName(String name) { this.name = name; }
+}

spring-boot-modules/spring-boot-api-versioning/src/main/java/com/baeldung/example/apiversioning/model/UserV2.java

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+package com.baeldung.example.apiversioning.model;
+
+public class UserV2 {
+    private String name;
+    private String email;
+    private int age;
+
+    public UserV2(String name, String email, int age) {
+        this.name = name;
+        this.email = email;
+        this.age = age;
+    }
+
+    // getters
+    public String getName() { return name; }
+    public String getEmail() { return email; }
+    public int getAge() { return age; }
+}