Practical development: How to configure multiple data sources in Spring Boot

Table of contents

1. Introduction to Spring Boot

2. What is a data source?

3. What is multiple data sources?

4. How to configure multiple data sources in Spring Boot

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1. Introduction to Spring Boot

Spring Boot is an open source framework for creating standalone, production-grade Spring applications. It simplifies the development process of applications based on the Spring framework and is highly scalable and flexible.

The main features and advantages of Spring Boot include:

1. Simplified configuration: Spring Boot adopts the principle of convention over configuration. Through automatic configuration and default configuration, it reduces the developer's configuration workload and improves development efficiency.

2. Embedded server: Spring Boot has embedded common web servers, such as Tomcat, Jetty, etc., which can run and deploy applications directly without additional configuration.

3. Automatic configuration: Spring Boot automatically completes related configurations, such as database connections, caching, etc., based on application dependencies and configuration files, simplifying the tedious configuration process.

4. Health check: Spring Boot provides a health check function, which can monitor the running status of the application and provide visual running status information.

5. Powerful development tools: Spring Boot integrates a wealth of development tools, such as Spring Boot CLI, Spring Boot Starter, Spring Boot DevTools, etc., which improves development experience and efficiency.

6. Microservice support: Spring Boot provides support for microservice architecture, which can quickly build independent, deployable microservice applications.

7. Easy to test: Spring Boot provides rich testing support, making it easy to write unit tests, integration tests and end-to-end tests.

8. Ecosystem: Spring Boot is part of the Spring ecosystem and can be seamlessly integrated with other Spring projects, such as Spring Data, Spring Security, etc., providing more functions and scalability.

In short, Spring Boot simplifies the development and deployment process of Spring applications and provides a wealth of functions and tools, allowing developers to focus more on the implementation of business logic and quickly build high-quality applications.

2. What is a data source?

Data source refers to the place or system where data is stored, which can be a database, file system, network service, etc. It is the source from which the application obtains data. Data sources can be relational databases (such as MySQL, Oracle, SQL Server), non-relational databases (such as MongoDB, Redis), file systems (such as local files, Hadoop distributed file systems), Web services (such as RESTful API), Message queue (such as RabbitMQ, Kafka), etc.

By configuring the data source, the application can connect to the corresponding data storage system and perform data read, write, update, and delete operations. A data source provides a set of interfaces or APIs for use by applications to facilitate the manipulation and management of data.

The advantage of using data sources is that it can achieve centralized management and unified access to data, simplifying the interaction process between applications and data storage systems. At the same time, by configuring different data sources, applications can connect to different types of data storage systems and flexibly process different types of data.

Data sources can also provide connection pooling, transaction management, caching and other functions to improve application performance and concurrent processing capabilities.

In short, the data source is the source from which the application obtains data. It can be various types of data storage systems, which provide interfaces and tools to manage and operate data. Applications can access and process data by configuring data sources.

3. What is multiple data sources?

Multiple data sources refers to connecting and operating multiple different data sources simultaneously in one application. Normally, an application only connects to one data source for data access and operation. However, in some complex scenarios, it may need to connect to multiple different data sources at the same time. For example, it needs to operate multiple relational databases and non-relational databases at the same time. Database or other data storage system.

The main purpose of using multiple data sources is to achieve distributed storage and management of data, and store different types of data in different data sources to meet different business needs. Multiple data sources can bring several benefits, such as:

1. Data isolation: Different data sources can store different types of data. Data isolation and management can be achieved through multiple data sources to avoid data chaos and conflicts.

2. Business splitting: By distributing different business data in different data sources, business splitting and decoupling can be achieved, improving the flexibility and maintainability of the system.

3. Performance optimization: By distributing query and operation loads among multiple data sources, the system's performance and concurrent processing capabilities can be improved.

4. Selection of multiple data sources: Different data sources may have different characteristics and advantages. By using multiple data sources, the most suitable data source can be selected according to specific business needs.

To implement the functionality of multiple data sources, it is usually necessary to configure multiple data sources in the application and write corresponding code to manage and operate these data sources. Some frameworks and tools, such as Spring Boot and MyBatis, provide support for multiple data sources, simplifying the configuration and management process of multiple data sources.

4. How to configure multiple data sources in Spring Boot

Configuring multiple data sources in Spring Boot can be achieved by following the following steps:

Add relevant dependencies: Add the corresponding database driver and Spring Boot database dependencies, such as MySQL, Oracle, etc., in pom.xml.

Create data source configuration: Add connection information for multiple data sources in the application.properties or application.yml configuration file . For example:

# 数据源1
spring.datasource.url=jdbc:mysql://localhost:3306/db1
spring.datasource.username=user1
spring.datasource.password=pass1
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

# 数据源2
spring.datasource.datasource2.url=jdbc:mysql://localhost:3306/db2
spring.datasource.datasource2.username=user2
spring.datasource.datasource2.password=pass2
spring.datasource.datasource2.driver-class-name=com.mysql.jdbc.Driver

Create data source beans: Create multiple data source DataSource Beans in the Spring Boot configuration class and inject the corresponding configuration information. For example:

@Configuration
public class DataSourceConfig {

    @Primary
    @Bean(name = "dataSource1")
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource dataSource1() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "dataSource2")
    @ConfigurationProperties(prefix = "spring.datasource.datasource2")
    public DataSource dataSource2() {
        return DataSourceBuilder.create().build();
    }
}

Create JdbcTemplate Bean: Create correspondingJdbcTemplate Bean for each data source to facilitate operations on each data source. For example:

@Configuration
public class JdbcTemplateConfig {

    @Primary
    @Bean(name = "jdbcTemplate1")
    public JdbcTemplate jdbcTemplate1(@Qualifier("dataSource1") DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }

    @Bean(name = "jdbcTemplate2")
    public JdbcTemplate jdbcTemplate2(@Qualifier("dataSource2") DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }
}

Use multiple data sources: Where needed, specify the specific data source and through the @Qualifier annotation. JdbcTemplate

@Service
public class MyService {

    @Autowired
    @Qualifier("jdbcTemplate1")
    private JdbcTemplate jdbcTemplate1;

    @Autowired
    @Qualifier("jdbcTemplate2")
    private JdbcTemplate jdbcTemplate2;

    // 使用jdbcTemplate1和jdbcTemplate2进行操作
}

Through the above steps, you can successfully configure and use multiple data sources in Spring Boot. More data sources can be configured according to actual needs and corresponding operations can be performed.

Multi-data source configuration also needs to consider issues such as transaction management and data source switching, which can be handled using Spring's transaction management. In addition, you can also consider using third-party libraries such as MyBatis to simplify the configuration and use of multiple data sources.