🏷 Spring Framework
4 patterns
Topic: Spring Framework
All Java patterns related to Spring Framework — java.evolved
Enterprise
Spring XML Bean Config vs Annotation-Driven
Old
<!-- applicationContext.xml -->
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="userRepository"
class="com.example.UserRepository">
<property name="dataSource" ref="dataSource"/>
</bean>
<bean id="userService"
class="com.example.UserService">
<property name="repository" ref="userRepository"/>
</bean>
</beans>
Modern
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
@Repository
public class UserRepository {
private final JdbcTemplate jdbc;
public UserRepository(JdbcTemplate jdbc) {
this.jdbc = jdbc;
}
}
@Service
public class UserService {
private final UserRepository repository;
public UserService(UserRepository repository) {
this.repository = repository;
}
}
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JDK 17+
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Enterprise
Spring Framework 7 API Versioning
Old
// Version 1 controller
@RestController
@RequestMapping("/api/v1/products")
public class ProductControllerV1 {
@GetMapping("/{id}")
public ProductDtoV1 getProduct(
@PathVariable Long id) {
return service.getV1(id);
}
}
// Version 2 — duplicated structure
@RestController
@RequestMapping("/api/v2/products")
public class ProductControllerV2 {
@GetMapping("/{id}")
public ProductDtoV2 getProduct(
@PathVariable Long id) {
return service.getV2(id);
}
}
Modern
// Configure versioning once
@Configuration
public class WebConfig implements WebMvcConfigurer {
@Override
public void configureApiVersioning(
ApiVersionConfigurer config) {
config.useRequestHeader("X-API-Version");
}
}
// Single controller, version per method
@RestController
@RequestMapping("/api/products")
public class ProductController {
@GetMapping(value = "/{id}", version = "1")
public ProductDtoV1 getV1(@PathVariable Long id) {
return service.getV1(id);
}
@GetMapping(value = "/{id}", version = "2")
public ProductDtoV2 getV2(@PathVariable Long id) {
return service.getV2(id);
}
}
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JDK 17+
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Enterprise
Spring Null Safety with JSpecify
Old
import org.springframework.lang.NonNull;
import org.springframework.lang.Nullable;
public class UserService {
@Nullable
public User findById(@NonNull String id) {
return repository.findById(id).orElse(null);
}
@NonNull
public List<User> findAll() {
return repository.findAll();
}
@NonNull
public User save(@NonNull User user) {
return repository.save(user);
}
}
Modern
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;
@NullMarked
public class UserService {
public @Nullable User findById(String id) {
return repository.findById(id).orElse(null);
}
public List<User> findAll() {
return repository.findAll();
}
public User save(User user) {
return repository.save(user);
}
}
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JDK 17+
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Enterprise
Spring Boot MVC Configuration
Old
@EnableWebMvc
@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {
@Override
public void addViewControllers(
ViewControllerRegistry registry) {
registry.addViewController("/").setViewName("home");
}
}
Modern
@Configuration
public class WebConfig implements WebMvcConfigurer {
@Override
public void addViewControllers(
ViewControllerRegistry registry) {
registry.addViewController("/").setViewName("home");
}
}
hover to see modern →
JDK 17+
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