"SpringBoot notes organization" detailed configuration of multiple data sources

Regarding the configuration of multiple data sources in springboot, I made notes today and shared them with friends in need. The power node Mr. Wang He said in the video,

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Video link: Power node springboot video tutorial-beginner springboot essential tutorial-springboot latest full version_哔哩哔哩_bilibili Your three links are the driving force for recording videos! Don't forget to bookmark, like, and coin~ This set of videos is based on the SpringBoot2.4 version. The tutorial starts with the details. Each case first explains the important dependencies in pom.xml, followed by the application configuration file, and finally the code implementation. Let you know why, and gradually let you master the automatic configuration of the SpringBoot framework, starter dependencies and other features. Why SpringBoot is to create Spring applications, you must understand spring-boot https://www.bilibili.com/video/BV1XQ4y1m7ex

1. Directory structure

Directory Structure

2. Dependency package (pom.xml)

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-configuration-processor</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.2</version>
    </dependency>
</dependencies>

3. Configuration file

server:
  port: 8080
spring:
  datasource:
    first:
      driver-class-name: com.mysql.jdbc.Driver
      jdbc-url: jdbc:mysql://localhost:3306/first?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true
      username: root
      password: root
    second:
      driver-class-name: com.mysql.jdbc.Driver
      jdbc-url: jdbc:mysql://localhost:3306/second?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true
      username: root
      password: root
  jpa:
    hibernate:
      ddl-auto: update
      naming:
        physical-strategy: org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy
        implicit-strategy: org.springframework.boot.orm.jpa.hibernate.SpringImplicitNamingStrategy
    show-sql: true
    database-platform: org.hibernate.dialect.MySQL5InnoDBDialect
    database: mysql

4. Multiple data source configuration (jpa)

1. DataSourceConfiguration

package com.cetc.config;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import javax.sql.DataSource;

/**
 * 数据库配置
 */
@Configuration
public class DataSourceConfiguration {

    /**
     *  第一个数据连接，默认优先级最高
     * @return
     */
    @Bean(name = "dataSourceFirst")
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource.first")
    public DataSource dataSourceFirst() {
        //这种方式的配置默认只满足spring的配置方式，如果使用其他数据连接（druid）,需要自己独立获取配置
        return DataSourceBuilder.create().build();
    }

    /**
     * 第二个数据源
     * @return
     */
    @Bean(name = "dataSourceSecond")
    @ConfigurationProperties(prefix = "spring.datasource.second")
    public DataSource dataSourceSecond() {
        return DataSourceBuilder.create().build();
    }
}

Explanation: In fact, the configuration here has been completed, and two data sources are configured here. You can add the corresponding JdbcTemplate, which is relatively simple and will not be introduced here.   

2. JpaFirstConfiguration

package com.cetc.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateSettings;
import org.springframework.boot.autoconfigure.orm.jpa.JpaProperties;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.persistence.EntityManager;
import javax.sql.DataSource;

/**
 * 第一个数据源，jpa的相关配置
 */
@Configuration
@EntityScan(basePackages = "com.cetc.domain.first")
//1、实体扫描
//2、实体管理ref
//3、事务管理
@EnableJpaRepositories(
        basePackages = "com.cetc.repository.first",
        entityManagerFactoryRef = "firstEntityManagerFactoryBean",
        transactionManagerRef = "firstTransactionManager")
@EnableTransactionManagement
public class JpaFirstConfiguration {

    //第一个数据源，可以不加Qualifier
    @Autowired
    @Qualifier("dataSourceFirst")
    private DataSource dataSource;

    //jpa其他参数配置
    @Autowired
    private JpaProperties jpaProperties;

    //实体管理工厂builder
    @Autowired
    private EntityManagerFactoryBuilder factoryBuilder;

    /**
     * 配置第一个实体管理工厂的bean
     * @return
     */
    @Bean(name = "firstEntityManagerFactoryBean")
    @Primary
    public LocalContainerEntityManagerFactoryBean entityManagerFactoryBean() {
        return factoryBuilder.dataSource(dataSource)
                //这一行的目的是加入jpa的其他配置参数比如（ddl-auto: update等）
                //当然这个参数配置可以在事务配置的时候也可以
                .properties(jpaProperties.getHibernateProperties(new HibernateSettings()))
                .packages("com.cetc.domain.first")
                .persistenceUnit("firstPersistenceUnit")
                .build();
    }

    /**
     * EntityManager不过解释，用过jpa的应该都了解
     * @return
     */
    @Bean(name = "firstEntityManager")
    @Primary
    public EntityManager entityManager() {
        return entityManagerFactoryBean().getObject().createEntityManager();
    }

    /**
     * jpa事务管理
     * @return
     */
    @Bean(name = "firstTransactionManager")
    @Primary
    public JpaTransactionManager transactionManager() {
        JpaTransactionManager jpaTransactionManager = new JpaTransactionManager();
        jpaTransactionManager.setEntityManagerFactory(entityManagerFactoryBean().getObject());
        return jpaTransactionManager;
    }
}

3. JpaSecondConfiguration

package com.cetc.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateSettings;
import org.springframework.boot.autoconfigure.orm.jpa.JpaProperties;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.persistence.EntityManager;
import javax.sql.DataSource;

/**
 * 第二个数据源，jpa的相关配置
 */
@Configuration
@EntityScan(basePackages = "com.cetc.domain.second")
//1、实体扫描
//2、实体管理ref
//3、事务管理
@EnableJpaRepositories(
        basePackages = "com.cetc.repository.second",
        entityManagerFactoryRef = "secondEntityManagerFactoryBean",
        transactionManagerRef = "secondTransactionManager")
@EnableTransactionManagement
public class JpaSecondConfiguration {

    //第二个数据源，必须加Qualifier
    @Autowired
    @Qualifier("dataSourceSecond")
    private DataSource dataSource;

    //jpa其他参数配置
    @Autowired
    private JpaProperties jpaProperties;

    //实体管理工厂builder
    @Autowired
    private EntityManagerFactoryBuilder factoryBuilder;

    /**
     * 配置第二个实体管理工厂的bean
     * @return
     */
    @Bean(name = "secondEntityManagerFactoryBean")
    public LocalContainerEntityManagerFactoryBean entityManagerFactoryBean() {
        return factoryBuilder.dataSource(dataSource)
                .properties(jpaProperties.getHibernateProperties(new HibernateSettings()))
                .packages("com.cetc.domain.second")
                .persistenceUnit("secondPersistenceUnit")
                .build();
    }

    /**
     * EntityManager不过解释，用过jpa的应该都了解
     * @return
     */
    @Bean(name = "secondEntityManager")
    public EntityManager entityManager() {
        return entityManagerFactoryBean().getObject().createEntityManager();
    }

    /**
     * jpa事务管理
     * @return
     */
    @Bean(name = "secondTransactionManager")
    public JpaTransactionManager transactionManager() {
        JpaTransactionManager jpaTransactionManager = new JpaTransactionManager();
        jpaTransactionManager.setEntityManagerFactory(entityManagerFactoryBean().getObject());
        return jpaTransactionManager;
    }
}