数据源代码：

            第一个读取配置文件代码：

package com.datasource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
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 org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration // 注册到springboot容器中
@MapperScan(basePackages = "com.bdqn.dao", sqlSessionFactoryRef = "test1SqlSessionFactory")
public class TestDatasource01 {

/**
*
* @methodDesc: 功能描述:(配置test1数据库)
*
*/
@Bean(name = "test1DataSource")
@ConfigurationProperties(prefix = "spring.datasource.test1")
// @Primary//自动装配时当出现多个Bean候选者时，被注解为@Primary的Bean将作为首选者，否则将抛出异常
public DataSource testDataSource() {
return DataSourceBuilder.create().build();
}

/**
*
* @methodDesc: 功能描述:(test1 sql会话工厂)
*/
@Bean(name = "test1SqlSessionFactory")
public SqlSessionFactory testSqlSessionFactory(@Qualifier("test1DataSource") DataSource dataSource)
throws Exception {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
// bean.setMapperLocations(
// new
// PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test1/*.xml"));
return bean.getObject();
}

/**
*
* @methodDesc: 功能描述:(test1 事物管理)
*
*/
@Bean(name = "test1TransactionManager")
public DataSourceTransactionManager testTransactionManager(@Qualifier("test1DataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
}

@Bean(name = "test1SqlSessionTemplate")
public SqlSessionTemplate testSqlSessionTemplate(
@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
return new SqlSessionTemplate(sqlSessionFactory);
}

}

  第二个读取配置文件代码：

package com.datasource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
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 org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration // 注册到springboot容器中
@MapperScan(basePackages = "com.bdqn01.dao", sqlSessionFactoryRef = "test2SqlSessionFactory")
public class TestDatasource02 {
/**
*
* @methodDesc: 功能描述:(配置test2数据库)
*/
@Bean(name = "test2DataSource")
@ConfigurationProperties(prefix = "spring.datasource.test2")
public DataSource testDataSource() {
return DataSourceBuilder.create().build();
}

/**
*
* @methodDesc: 功能描述:(test2 sql会话工厂)

*/
@Bean(name = "test2SqlSessionFactory")
public SqlSessionFactory testSqlSessionFactory(@Qualifier("test2DataSource") DataSource dataSource)
throws Exception {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
// bean.setMapperLocations(
// new
// PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test2/*.xml"));
return bean.getObject();
}

/**
*
* @methodDesc: 功能描述:(test2 事物管理)
*/
@Bean(name = "test2TransactionManager")
public DataSourceTransactionManager testTransactionManager(@Qualifier("test2DataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
}

@Bean(name = "test2SqlSessionTemplate")
public SqlSessionTemplate testSqlSessionTemplate(
@Qualifier("test2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
return new SqlSessionTemplate(sqlSessionFactory);
}
}

启动报错信息：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaMappingContext': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: At least one JPA metamodel must be present!
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1702) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:579) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:741) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at com.start.main(start.java:11) [classes/:na]
Caused by: java.lang.IllegalArgumentException: At least one JPA metamodel must be present!
at org.springframework.util.Assert.notEmpty(Assert.java:450) ~[spring-core-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.data.jpa.mapping.JpaMetamodelMappingContext.<init>(JpaMetamodelMappingContext.java:54) ~[spring-data-jpa-2.0.6.RELEASE.jar:2.0.6.RELEASE]
at org.springframework.data.jpa.repository.config.JpaMetamodelMappingContextFactoryBean.createInstance(JpaMetamodelMappingContextFactoryBean.java:88) ~[spring-data-jpa-2.0.6.RELEASE.jar:2.0.6.RELEASE]
at org.springframework.data.jpa.repository.config.JpaMetamodelMappingContextFactoryBean.createInstance(JpaMetamodelMappingContextFactoryBean.java:43) ~[spring-data-jpa-2.0.6.RELEASE.jar:2.0.6.RELEASE]
at org.springframework.beans.factory.config.AbstractFactoryBean.afterPropertiesSet(AbstractFactoryBean.java:141) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1761) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1698) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
... 16 common frames omitted

Process finished with exit code 1

原因没有指定主数据源

    第一个数据源代码修改如下

package com.datasource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
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 org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration // 注册到springboot容器中
@MapperScan(basePackages = "com.bdqn.dao", sqlSessionFactoryRef = "test1SqlSessionFactory")
public class TestDatasource01 {

/**
*
* @methodDesc: 功能描述:(配置test1数据库)
*
*/
@Bean(name = "test1DataSource")
@ConfigurationProperties(prefix = "spring.datasource.test1")
@Primary//自动装配时当出现多个Bean候选者时，被注解为@Primary的Bean将作为首选者，否则将抛出异常
public DataSource testDataSource() {
return DataSourceBuilder.create().build();
}

/**
*
* @methodDesc: 功能描述:(test1 sql会话工厂)
*/
@Bean(name = "test1SqlSessionFactory")
@Primary//自动装配时当出现多个Bean候选者时，被注解为@Primary的Bean将作为首选者，否则将抛出异常
public SqlSessionFactory testSqlSessionFactory(@Qualifier("test1DataSource") DataSource dataSource)
throws Exception {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
// bean.setMapperLocations(
// new
// PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test1/*.xml"));
return bean.getObject();
}

/**
*
* @methodDesc: 功能描述:(test1 事物管理)
*
*/
@Bean(name = "test1TransactionManager")
@Primary//自动装配时当出现多个Bean候选者时，被注解为@Primary的Bean将作为首选者，否则将抛出异常
public DataSourceTransactionManager testTransactionManager(@Qualifier("test1DataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
}

@Bean(name = "test1SqlSessionTemplate")
@Primary//自动装配时当出现多个Bean候选者时，被注解为@Primary的Bean将作为首选者，否则将抛出异常
public SqlSessionTemplate testSqlSessionTemplate(
@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
return new SqlSessionTemplate(sqlSessionFactory);
}

}