Spring Data Jpa 多数据源配置（mysql 和 orcle）过程

参考文章：基于Spring Data JPA支持多数据源
Spring Data JPA 之 多数据源配置
spring boot下基于spring data jpa配置mysql+达梦多数据源（以不同包路径方式，mysql为主数据源）

1、修改配置文件

spring:
  datasource:
    primary:
      driver-class-name: com.mysql.cj.jdbc.Driver
      jdbc-url: 
      username: 
      password:


    secondary:
      driver-class-name: oracle.jdbc.OracleDriver
      jdbc-url: 
      username:
      password: 

2、引入依赖

   <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>
            <version>${mysql-connector-java.version}</version>
        </dependency>
        <dependency>
            <groupId>com.oracle</groupId>
            <artifactId>ojdbc7</artifactId>
            <version>12.1.0.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.24</version>
        </dependency>
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-json</artifactId>
        </dependency>
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-extra</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.76</version>
        </dependency>

    </dependencies>

3、配置文件

需要将不同数据源放在不同包下分别扫描
这里用的主数据源的包名：primary ， 辅数据源包名：Secondary

3.1、 DataSourceConfig 配置文件

直接照搬无需修改

package com.ruiling.zhaigua.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateProperties;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateSettings;
import org.springframework.boot.autoconfigure.orm.jpa.JpaProperties;
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;
import java.util.Map;

/**
 * @author xingyu.wu
 * @date 2023/9/27 15:18
 * @email [email protected]
 */
@Configuration
public class DataSourceConfig {

    // 不少教程是把jpaProperties、hibernateProperties、getVendorProperties放到具体的JPA配置中，代码重复冗余。
    // 可以把这两个属性、一个方法在这里自动注入来初始化，然后在对应的JPA配置中自动注入即可
    @Autowired
    private JpaProperties jpaProperties;

    @Autowired
    private HibernateProperties hibernateProperties;

    // 自动注入时的对象名称
    @Bean(name = "vendorProperties")
    public Map<String, Object> getVendorProperties() {
        return hibernateProperties
                .determineHibernateProperties(jpaProperties.getProperties(), new HibernateSettings());
    }

    // 主数据源，加上 @Primary。
    @Primary
    // 自动注入时的对象名称
    @Bean(name = "primaryDataSource")
    // 主数据源的配置项前缀
    @ConfigurationProperties("spring.datasource.primary")
    public DataSource primaryDataSource() {
        return DataSourceBuilder.create().build();
    }

    // 自动注入时的对象名称
    @Bean(name = "secondaryDataSource")
    // 辅助数据源的配置项前缀
    @ConfigurationProperties("spring.datasource.secondary")
    public DataSource secondaryDataSource() {
        return DataSourceBuilder.create().build();
    }

}

3.2、PrimaryConfig 配置文件

需要修改 repository 路径 与 实体类路径

package com.ruiling.zhaigua.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
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.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.persistence.EntityManager;
import javax.sql.DataSource;
import java.util.Map;

/**
 * @author xingyu.wu
 * @date 2023/9/27 11:26
 * @email [email protected]
 */
@SuppressWarnings("ConstantConditions")
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(  // 利⽤ EnableJpaRepositories 配置哪些包下⾯的 Repositories，采⽤哪个 EntityManagerFactory 和哪个 TransactionManagement
        basePackages = {"com.ruiling.zhaigua.primary.repository"},// 改这里！！master 数据源的 repository 的包路径
        entityManagerFactoryRef = "entityManagerFactoryPrimary",// 改变 master 数据源的 EntityManagerFactory 的默认值，改为 masterEntityManagerFactory
        transactionManagerRef = "transactionManagerPrimary" // 改变 master 数据源的 TransactionManagement 的默认值，masterTransactionManager
)
public class PrimaryConfig  {

    @Autowired
    @Qualifier("primaryDataSource")
    private DataSource primaryDataSource;

    // 自动注入在配置类中提供的初始化方法
    @Autowired
    @Qualifier("vendorProperties")
    private Map<String, Object> vendorProperties;

    @Primary
    @Bean(name = "entityManagerFactoryPrimary")
    public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary(
            EntityManagerFactoryBuilder builder) {
//        final HashMap hibernateProperties = new HashMap();
//        hibernateProperties.put("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");

        // 指定模型类的包名
        return builder
                .dataSource(primaryDataSource)
                .properties(vendorProperties)//配置方言
                .packages("com.ruiling.zhaigua.primary.model")//和这里
                .persistenceUnit("primaryPersistenceUnit")
                .build();
    }

    @Primary
    @Bean(name = "entityManagerPrimary")
    public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
        return entityManagerFactoryPrimary(builder).getObject().createEntityManager();
    }

    @Primary
    @Bean(name = "transactionManagerPrimary")
    PlatformTransactionManager transactionManagerPrimary(EntityManagerFactoryBuilder builder) {
        return new JpaTransactionManager(entityManagerFactoryPrimary(builder).getObject());
    }

}

3.3、 SecondaryConfig配置文件

修改同上

package com.ruiling.zhaigua.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
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.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.persistence.EntityManager;
import javax.sql.DataSource;
import java.util.Map;


/**
 * @author xingyu.wu
 * @date 2023/9/27 11:31
 * @email [email protected]
 */
@SuppressWarnings("ConstantConditions")
@Configuration
@EnableTransactionManagement
// 指定Secondary数据源Repository的包名
@EnableJpaRepositories(
        entityManagerFactoryRef="entityManagerFactorySecondary",
        transactionManagerRef="transactionManagerSecondary",
        basePackages= {"com.ruiling.zhaigua.secondary.repository"}) //改这里！！
public class SecondaryConfig {

    @Autowired
    @Qualifier("secondaryDataSource")
    private DataSource secondaryDataSource;

    // 自动注入在配置类中提供的初始化方法
    @Autowired
    @Qualifier("vendorProperties")
    private Map<String, Object> vendorProperties;

    @Bean(name = "entityManagerFactorySecondary")
    public LocalContainerEntityManagerFactoryBean entityManagerFactorySecondary (
            EntityManagerFactoryBuilder builder) {
//        final HashMap hibernateProperties = new HashMap();
//        hibernateProperties.put("hibernate.dialect", "org.hibernate.dialect.OracleDialect");
        // 指定模型类的包名
        return builder
                .dataSource(secondaryDataSource)
                .properties(vendorProperties)
                .packages("com.ruiling.zhaigua.secondary.model")//和这里
                .persistenceUnit("secondaryPersistenceUnit")
                .build();
    }

    @Bean(name = "entityManagerSecondary")
    public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
        return entityManagerFactorySecondary(builder).getObject().createEntityManager();
    }

    @Bean(name = "transactionManagerSecondary")
    PlatformTransactionManager transactionManagerSecondary(EntityManagerFactoryBuilder builder) {
        return new JpaTransactionManager(entityManagerFactorySecondary(builder).getObject());
    }
}

4、遇到的问题

1、 在配置完成后可能会出现找不到entityManagerFactory类

解决办法：
最后发现Application启动类中加了@EnableJpaRepositories 注解后会默认扫描entityManagerFactory，注释掉解决完成。

@EnableAsync
@SpringBootApplication
//@EnableJpaRepositories  //将这里注释掉
@Import(cn.hutool.extra.spring.SpringUtil.class)
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

参考：https://blog.csdn.net/weixin_42465269/article/details/117783565

2、其他问题可参考

spring boot下基于spring data jpa配置mysql+达梦多数据源（以不同包路径方式，mysql为主数据源）
最后