多資料來源就是連線多個數據庫

1、在application.properties中配置兩個資料庫

spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=root

spring.datasource.test2.driverClassName=com.mysql.jdbc.Driver
spring.datasource.test2.url=jdbc:mysql://localhost:3306/test2?characterEncoding=UTF-8
spring.datasource.test2.username=root
spring.datasource.test2.password=root

spring.thymeleaf.mode=HTML5
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.content-type=text/html
#開發時關閉快取，不然沒法看到實時頁面
spring.thymeleaf.cache=false
 

2、建立兩個資料庫配置類（DataSourceConfig、DataSourceConfig2）

package com.cppdy.config;

import javax.sql.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.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 org.springframework.jdbc.datasource.DataSourceTransactionManager;

//配置mapper所在的包
@Configuration
@MapperScan(basePackages="com.cppdy.mapper.test1",sqlSessionTemplateRef="testSqlSessionTemplate")
public class DataSourceConfig {
    
    @Bean(name="testDataSource")
    @ConfigurationProperties(prefix="spring.datasource")
    //primary代表主庫
    @Primary
    public DataSource testDateSource() {
        return DataSourceBuilder.create().build();
    }
    
    @Bean(name="testSqlSessionFactory")
    @Primary
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("testDataSource") DataSource dataSource) throws Exception{
        SqlSessionFactoryBean bean=new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        return bean.getObject();
    }
    
    @Bean(name="testTransactionManager")
    @Primary
    public DataSourceTransactionManager testTransactionManager(@Qualifier("testDataSource") DataSource dataSource){
        return new DataSourceTransactionManager(dataSource);
    }
    
    @Bean(name="testSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("testSqlSessionFactory") SqlSessionFactory sqlSessionFactory){
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

package com.cppdy.config;

import javax.sql.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.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.jdbc.datasource.DataSourceTransactionManager;

//配置mapper所在的包
@Configuration
@MapperScan(basePackages = "com.cppdy.mapper.test2", sqlSessionTemplateRef = "test2SqlSessionTemplate")
public class DataSourceConfig2 {

    @Bean(name = "test2DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.test2")
    public DataSource testDateSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "test2SqlSessionFactory")
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("test2DataSource") DataSource dataSource)
            throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        return bean.getObject();
    }

    @Bean(name = "test2TransactionManager")
    public DataSourceTransactionManager testTransactionManager(@Qualifier("test2DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

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

}

3、在mapper資料夾下建立test1、tests2資料夾，並在兩個資料夾下分別建立（UserMapper、UserMapper2）

package com.cppdy.mapper.test1;

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import com.cppdy.entity.User;

@Mapper
public interface UserMapper {

    @Select("select * from user where id=#{id}")
    User getUserById(@Param("id") int id);

    @Insert("insert into user values(NULL,#{name})")
    User insertUser(@Param("name") String name);
    
    @Update("update user set username=#{name} where id=#{id}")
    User update(@Param("id") int id,@Param("name") String name);
    
    @Delete("delete from user where id=#{id}")
    User delete(@Param("id") int id);
}

package com.cppdy.mapper.test2;

import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

import com.cppdy.entity.User;

@Mapper
public interface UserMapper2 {
    
    @Select("select * from user where id=#{id}")
    User getUserById(@Param("id") int id);

}

4、在HelloWordController中建立測試方法

@RequestMapping("getUserById2")
    public User getUserById2() {

        return userMapper2.getUserById(1);
    }

5、分別呼叫getUserById和getUserById2方法，測試從兩個資料庫分別獲取使用者資訊