Transaction Management in Spring Boot

In actual development, transaction is a very important concept. In Spring Boot, we can use a transaction manager to manage transactions. The transaction manager can ensure that a series of operations either all succeed or all fail, thus ensuring data consistency and integrity. In this article, we will introduce what a transaction in Spring Boot is, how it works, and how to use it.

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business concept

Atomicity: All operations of a transaction either succeed or fail.
Consistency (consistency): Before and after the transaction is executed, the integrity and consistency of the data remain unchanged.
Isolation: The execution of transactions is not interfered with by other transactions, that is, concurrently executed transactions should be isolated from each other.
Durability: After a transaction is committed, its results should be permanently stored in the database.

Transactions in Spring Boot

In Spring Boot, we can use a transaction manager to manage transactions. The transaction manager can ensure that a series of operations either all succeed or all fail, thus ensuring data consistency and integrity.

The transaction manager in Spring Boot is implemented through AOP (aspect-oriented programming), which can intercept methods annotated with @Transactional and automatically open and commit transactions before and after method execution. If an exception occurs during method execution, the transaction manager will automatically roll back the transaction to ensure data consistency and integrity.

@Transactional annotation

In Spring Boot, we can use the @Transactional annotation to declare that a method requires transaction management. The @Transactional annotation has the following attributes:

propagation: The propagation behavior of the transaction, the default value is Propagation.REQUIRED.
isolation: The isolation level of the transaction, the default value is Isolation.DEFAULT.
readOnly: Whether the transaction is read-only, the default value is false.
timeout: the timeout period of the transaction, the default value is -1 (meaning no timeout period is set).
rollbackFor: The exception type that needs to be rolled back, the default value is Exception.class.
noRollbackFor: Exception types that do not require rollback, the default value is {}.

Here is an example using the @Transactional annotation:

@Service
public class UserServiceImpl implements UserService {
    
    

    @Autowired
    private UserRepository userRepository;

    @Override
    @Transactional
    public void createUser(User user) {
    
    
        userRepository.save(user);
    }

}

In the above example, we used the @Transactional annotation to declare a method createUser(), which is used to create a user. If an exception occurs during method execution, the transaction manager will automatically roll back the transaction to ensure data consistency and integrity.

In addition, we can also use the @Transactional annotation on the class to declare that all methods in a class need transaction management. Here is an example:

@Service
@Transactional
public class UserServiceImpl implements UserService {
    
    

    @Autowired
    private UserRepository userRepository;

    @Override
    public void createUser(User user) {
    
    
        userRepository.save(user);
    }

}

In the above example, we used the @Transactional annotation on the class, which will take effect for all methods in the class.

Configuration of the transaction manager

By default in Spring Boot, org.springframework.jdbc.datasource.DataSourceTransactionManager is used as the transaction manager. If you are using JPA, org.springframework.orm.jpa.JpaTransactionManager is used by default. If you are using MyBatis, org.mybatis.spring.SqlSessionTransactionManager is used by default.

If we need a custom transaction manager, we can use the @Bean annotation to define a transaction manager in the configuration class. Here is an example:

@Configuration
@EnableTransactionManagement
public class TransactionConfig {
    
    

    @Autowired
    private DataSource dataSource;

    @Bean
    public PlatformTransactionManager transactionManager() {
    
    
        return new DataSourceTransactionManager(dataSource);
    }

}

In the above example, we use the @Bean annotation to define a DataSourceTransactionManager instance and return it as the transaction manager. In addition, we also use the @EnableTransactionManagement annotation to enable Spring Boot's transaction management function.

Summarize

A transaction is a set of operations that either all succeed or all fail. If one operation fails in a set of operations, the entire transaction should be rolled back, that is, the operations that have been performed should be undone, so as to ensure data consistency and integrity. In Spring Boot, we can use a transaction manager to manage transactions. The transaction manager can ensure that a series of operations either all succeed or all fail, thus ensuring data consistency and integrity. The transaction manager in Spring Boot is implemented through AOP, which can intercept methods annotated with @Transactional and automatically open and commit transactions before and after method execution. If an exception occurs during method execution, the transaction manager will automatically roll back the transaction to ensure data consistency and integrity. If we need a custom transaction manager, we can use the @Bean annotation to define a transaction manager in the configuration class.