Spring Boot realizes the coordination and management of distributed transactions

Spring Boot realizes the coordination and management of distributed transactions

Introduction

In modern distributed systems, there are often situations where multiple services cooperate to complete a business operation. In this case, how to ensure the data consistency of all services has become an important issue. As a popular Java development framework, Spring Boot provides a variety of methods to realize the coordination and management of distributed transactions. This article will introduce some common methods and technologies to solve the problem of distributed transactions.

1. Introduce a distributed transaction manager

The distributed transaction manager is the infrastructure for implementing distributed transactions. Spring Boot can integrate a variety of distributed transaction managers, such as Atomikos, Bitronix, Narayana, etc. These transaction managers provide the coordination and management capabilities of distributed transactions, and can ensure the consistency of transaction operations among multiple services.

1.1 Introducing dependencies

First, you need to pom.xmlintroduce the corresponding distributed transaction manager dependencies in the file. Taking Atomikos as an example, <dependencies>the following dependencies can be added to the node:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jta-atomikos</artifactId>
</dependency>

1.2 Configure transaction manager

Configure the distributed transaction manager in a Spring Boot configuration file such as application.propertiesor . application.ymlHere is an example configuration for Atomikos:

spring:
  jta:
    atomikos:
      properties:
        com.atomikos.icatch.service: com.atomikos.icatch.standalone.UserTransactionServiceFactory
        com.atomikos.icatch.log_base_name: /path/to/transaction-logs/txlog
      datasource:
        xa-data-source-class-name: com.mysql.cj.jdbc.MysqlXADataSource
        unique-resource-name: myDataSource
        xa-properties:
          URL: jdbc:mysql://localhost:3306/mydatabase
          user: myuser
          password: mypassword

In the above configuration, com.atomikos.icatch.servicethe transaction log file path of Atomikos is specified, and datasourcethe node specifies the connection information of the database.

2. Use distributed transaction annotations

Spring Boot provides various annotations to declare and manage distributed transactions. Using these annotations can easily define transaction boundaries and control transaction commit and rollback.

2.1 @TransactionalNotes

@TransactionalIt is Spring's core transaction annotation, which can be used on methods or classes. Using annotations on methods @Transactionalcan declare a transaction boundary, and perform operations within the method as a transaction. The sample code is as follows:

@Service
public class UserService {
    
    

    @Autowired
    private UserRepository userRepository;

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

In the above example, createUserthe method is declared as

A transaction, when the method is executed, if an exception occurs, the transaction will be rolled back to ensure data consistency.

2.2 @Transactional(propagation = Propagation.REQUIRES_NEW)Notes

Sometimes, we may need to call methods of other services in a transaction, and these methods may also require independent transactions. In this case, @Transactional(propagation = Propagation.REQUIRES_NEW)annotations can be used to declare a new transaction. The sample code is as follows:

@Service
public class OrderService {
    
    

    @Autowired
    private UserService userService;

    @Transactional
    public void createOrder(Order order) {
    
    
        // 创建订单逻辑...

        // 调用用户服务创建用户
        userService.createUser(order.getUser());

        // 其他业务逻辑...
    }
}

In the above example, createOrderthe method is declared as a transaction, and when userService.createUserthe method is called, a new transaction is started.

3. Consistency Guarantee of Distributed Transactions

In a distributed system, to ensure the data consistency of all services, mechanisms such as Two-Phase Commit or Compensating Transaction are usually required.

3.1 Two-Phase Commit

Two-phase commit is a commonly used distributed transaction coordination protocol. It consists of two stages:

1. Prepare Phase (Prepare Phase): The transaction coordinator sends prepare requests to participants (each service) and waits for responses from participants. After receiving the prepare request, the participants will perform local transaction operations and send the results (transaction logs) to the transaction coordinator.
2. Commit Phase: If the preparation requests of all participants have received a normal response, the transaction coordinator will send a commit request to all participants and wait for the participants' responses. After receiving the submission request, the participant will formally submit the transaction and send the submission result to the transaction coordinator.

Spring Boot can implement two-phase commit by integrating a distributed transaction manager. You only need to use annotations on methods or classes @Transactional, and the framework will automatically handle transaction commit and rollback.

3.2 Compensating Transaction

Compensating transactions are another commonly used mechanism for distributed transaction processing. It solves the consistency problem of distributed transactions by adding compensation logic in business logic. When a service execution fails, the previous operation can be undone by performing the corresponding compensation operation, so as to achieve data consistency.

The use of compensation transactions requires the design of business logic to ensure that rollback or compensation operations can be performed. In Spring Boot, the processing of compensation transactions can be realized by writing corresponding compensation logic.

in conclusion

Spring Boot provides a variety of ways

To achieve the coordination and management of distributed transactions. By introducing a distributed transaction manager, using @Transactionalannotations, and adopting a two-phase commit or compensation transaction mechanism, data consistency among multiple services in a distributed system can be effectively guaranteed. According to specific business scenarios and requirements, choosing an appropriate distributed transaction processing mechanism and rationally designing business logic can effectively solve the problem of distributed transactions.