因项目需要在一个应用里从两个数据库取数，所以需要配置多数据源，网上找了好多方法才启动成功，整理如下。注意两个数据源repository所在的文件夹名称不能相同，否则系统启动会报错。

配置文件

spring.datasource.primary.url=***
spring.datasource.primary.username=***
spring.datasource.primary.password=***
spring.datasource.primary.driver-class-name=com.mysql.jdbc.Driver

spring.datasource.second.url=***
spring.datasource.second.username=***
spring.datasource.second.password=***
spring.datasource.second.driver-class-name=com.mysql.jdbc.Driver

通用数据源配置

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import javax.sql.DataSource;

/**
 * @author ruanshuai
 * @date 2020/5/13
 */

@Configuration
public class DataSourceConfig {

    /**
     * 第一个数据连接，默认优先级最高
     * @return
     */
    @Primary
    @Bean(name = "primaryDataSource") //数据源1配置名
    @Qualifier("primaryDataSource") //数据源1配置名
    @ConfigurationProperties(prefix="spring.datasource.primary") //见配置文件
    public DataSource PrimaryDataSource() {
        return DataSourceBuilder.create().type(DruidDataSource.class).build();
    }

    /**
     * 第二个数据源
     * @return
     */
    @Bean(name = "secondDataSource") //数据源2配置名
    @Qualifier("secondDataSource") //数据源2配置名
    @ConfigurationProperties(prefix="spring.datasource.second") //见配置文件
    public DataSource secondaryDataSource() {
        return DataSourceBuilder.create().type(DruidDataSource.class).build();
    }
}

数据源1配置

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.HashMap;
import java.util.Map;

/**
 * @author ruanshuai
 * @date 2020/5/13
 */

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef="entityManagerFactoryPrimary",
        transactionManagerRef="transactionManagerPrimary",
        basePackages= { "***此处为数据源1 repository的存放文件夹***" })
public class PrimaryConfig {


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

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

    @Primary
    @Bean(name = "entityManagerFactoryPrimary")
    public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary (EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(primaryDataSource)
                .properties(getVendorProperties())
                .packages("***实体类所在文件夹，两个数据源的实体类可相同***")
                .persistenceUnit("primaryPersistenceUnit")
                .build();
    }



    private Map<String, String> getVendorProperties() {
        Map<String, String> jpaProperties = new HashMap<>(16);
        jpaProperties.put("hibernate.hbm2ddl.auto", "update");
        jpaProperties.put("hibernate.show_sql", System.getProperty("spring.jpa.show-sql"));
        jpaProperties.put("hibernate.dialect", System.getProperty("spring.jpa.properties.hibernate.dialect"));
        jpaProperties.put("hibernate.current_session_context_class", "org.springframework.orm.hibernate5.SpringSessionContext");
        return jpaProperties;
    }

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

数据源2配置

import org.omg.CORBA.Environment;
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.HashMap;
import java.util.Map;

/**
 * @author ruanshuai
 * @date 2020/5/13
 */

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        //实体管理
        entityManagerFactoryRef="entityManagerFactorySecond",
        //事务管理
        transactionManagerRef="transactionManagerSecond",
        //实体扫描,设置Repository所在位置
        basePackages= { "***此处为数据源1 repository的存放文件夹***" })
public class SecondConfig {

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


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

    @Bean(name = "entityManagerFactorySecond")
    public LocalContainerEntityManagerFactoryBean entityManagerFactorySecond (EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(secondDataSource)
                .properties(getVendorProperties())
                .packages("***实体类所在文件夹，两个数据源的实体类可相同***")
                .persistenceUnit("secondPersistenceUnit")
                .build();
    }

    private Map<String, String> getVendorProperties() {
        Map<String, String> jpaProperties = new HashMap<>(16);
        jpaProperties.put("hibernate.hbm2ddl.auto", "update");
        jpaProperties.put("hibernate.show_sql", System.getProperty("spring.jpa.show-sql"));
        jpaProperties.put("hibernate.dialect", System.getProperty("spring.jpa.properties.hibernate.dialect"));
        jpaProperties.put("hibernate.current_session_context_class", "org.springframework.orm.hibernate5.SpringSessionContext");
        return jpaProperties;
    }

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