Detailed explanation of the transaction manager in the Java transaction API framework
Detailed explanation of the transaction manager in the Java transaction API framework
introduction:
When developing applications, transaction management is a key concept.The transaction is used to combine a series of operations into an atomer unit to ensure the consistency and integrity of the data.In Java, there are many transaction managers to choose from. These transaction managers provide powerful functions that enable developers to handle affairs easier.This article will introduce the transaction manager in the Java transaction API framework in detail and provide relevant code examples.
1. What is a transaction manager?
The transaction manager is an object for managing affairs.It is responsible for the implementation of control and coordination, and provides a set of API for developers.The transaction manager can automatically handle the start, submission and rollback of the transaction, and roll back and recover when necessary.
2. The main features of the Java transaction manager
Java transaction manager has the following main characteristics:
-Atomic: Affairs is a atomic unit, or all successfully executed or all fails.
-Sipinity: The consistency of data before and after transaction is maintained.
-Stochism: The execution between concurrent transactions is separated from each other, and the execution of a transaction will not affect the execution of other transactions.
-Suctive: After the transaction is submitted, the modification of the data will be preserved for a long time.
3. The implementation of the Java transaction manager
The Java transaction manager can use the following two methods for implementation:
-A programming transaction management: use programming methods to manage transactions, and developers can manually control the beginning, submission and rollback of transactions.This method is highly flexible, but it is necessary to compile a large number of transaction management code to develop a large number of transaction management code.
-Poltral transaction management: The border of the transaction is declared by annotation or configuration files, and the start, submission and rollback of the transaction manager will automatically handle the transaction.This method reduces the workload of manual writing transaction management code, enabling developers to focus more on the realization of business logic.
4. Spring transaction manager
The Spring framework provides a group of powerful transaction managers, which is one of the common choices for Java transactions.The Spring transaction manager supports programming management and statement management options: programming management and declarative transaction management.
The following is an example code that uses the Spring transaction manager:
@Service
@Transactional
public class ProductService {
@Autowired
private ProductRepository productRepository;
public void saveProduct(Product product) {
productRepository.save(product);
}
public void deleteProduct(Long productId) {
productRepository.deleteById(productId);
}
// Other business methods ...
}
In the above code, the annotation of `@transactional` is used to declare a transaction boundary, indicating that the method of` saveProduct` and `DeleteProdut` will be executed in the transaction.If the method executes successfully, the transaction will be submitted automatically; if the method is thrown abnormal, the transaction will roll back automatically.
5. Java EE transaction manager
The Java EE platform also provides a powerful transaction manager for developers.The Java EE transaction manager is mainly based on the API under the `javax.transaction`.You can declare the boundaries of transactions by annotation or configuration files, and control the beginning, submission and rollback through programming.
The following is an example code that uses the Java EE transaction manager:
@Stateless
public class ProductService {
@PersistenceContext
private EntityManager entityManager;
@Resource
private UserTransaction userTransaction;
public void saveProduct(Product product) {
try {
userTransaction.begin();
entityManager.persist(product);
userTransaction.commit();
} catch (Exception e) {
e.printStackTrace();
try {
userTransaction.rollback();
} catch (SystemException ex) {
ex.printStackTrace();
}
}
}
public void deleteProduct(Long productId) {
try {
userTransaction.begin();
Product product = entityManager.find(Product.class, productId);
entityManager.remove(product);
userTransaction.commit();
} catch (Exception e) {
e.printStackTrace();
try {
userTransaction.rollback();
} catch (SystemException ex) {
ex.printStackTrace();
}
}
}
// Other business methods ...
}
In the above code, the annotation of `@Stateless` indicates that this class is a stateless session bean for managing affairs.By injecting the `EntityManager` and` Usertransactions, database operations and transactions can be performed.
in conclusion:
The transaction manager in the Java transaction API framework is one of the very important components in developing applications.It provides many functions that can easily manage and handle affairs.Whether it is the Spring framework transaction manager or the Java EE platform's transaction manager, you can choose the appropriate way to achieve transaction management according to the specific needs.I hope this article will help you understand the Java transaction manager.
