Spring JPA事务管理与自定义操作实例解析(最新推荐)

@Repository
@Transactional(readOnly = true)
public class SimpleJpaRepository<T, ID> implements JpaRepository<T, ID>, JpaSpecificationExecutor<T> {
    @Transactional
    public void deleteById(ID id) {...}
    // 其他写操作
}

public interface EmployeeRepository extends CrudRepository<Employee, Long> {
    @Transactional(timeout = 10)
    @Override
    public void deleteById(ID id);
}

@Configuration
@ComponentScan
@EnableTransactionManagement
public class AppConfig {
    // ...
}

@Service
public class MyExampleBean{
    @Transactional
    public void saveChanges() {
        repo.save(..);
        repo.deleteById(..);
        .....
    }
}

@Entity
public class Employee {
    @Id
    @GeneratedValue
    private Long id;
    @Column(unique = true)
    private String name;
    private String dept;
    private int salary;
    // 省略其他字段和方法
}

public interface EmployeeRepository extends CrudRepository<Employee, Long> {
    @Transactional(timeout = 10)
    @Override
    <S extends Employee> S save(S s);
}

@Component
public class ExampleClient {
    @Autowired
    private EmployeeRepository repo;
    public void findEmployees() {
        System.out.println(" -- finding all employees --");
        repo.findAll().forEach(System.out::println);
    }
    @Transactional
    public void saveEmployees() {
        repo.save(Employee.create("Mike", "Sale", 1000));
        repo.save(Employee.create("Diana", "Admin", 3000));
        repo.save(Employee.create("Diana", "IT", 3200)); // 这将触发异常
    }
}

@EnableJpaRepositories
@ComponentScan
@Configuration
@EnableTransactionManagement
public class AppConfig {
    @Bean
    EntityManagerFactory entityManagerFactory() {
        EntityManagerFactory emf =
                Persistence.createEntityManagerFactory("example-unit");
        return emf;
    }
    @Bean
    public PlatformTransactionManager transactionManager() {
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(entityManagerFactory());
        return txManager;
    }
}

public class ExampleMain {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context =
                new AnnotationConfigApplicationContext(AppConfig.class);
        ExampleClient exampleClient = context.getBean(ExampleClient.class);
        try {
            exampleClient.saveEmployees();
        } catch (Exception e) {
            System.err.println(e);
        }
        exampleClient.findEmployees();
        EntityManagerFactory emf = context.getBean(EntityManagerFactory.class);
        emf.close();
    }
}