Spring-Boot-JDBC-Mybatis-配置多数据源-以及-采用Durid-作为连接池

1 配置文件

在配置文件中配置两个数据源配置，以及 mybatis xml 配置文件路径

# mybatis  多数据源配置
mybatis.config-location = classpath:mapper/config/mybatis-config.xml

#################  mysql  数据源 1 #################
spring.datasource.one.jdbc-url=jdbc:mysql://localhost:3306/user?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.one.username=root
spring.datasource.one.password=root
#spring.datasource.one.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.one.driver-class-name=com.mysql.jdbc.Driver
#################  mysql  数据源 1 #################

#################  mysql  数据源 2 ################
spring.datasource.second.jdbc-url=jdbc:mysql://xxxxxxxxxx:3306/user?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.second.username=root
spring.datasource.second.password=root
#spring.datasource.second.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.second.driver-class-name=com.mysql.jdbc.Driver
#################  mysql  数据源 1 #################

2 数据库配置代码：

1 步骤

1 首先加载配置的数据源：手动将数据配置文件信息注入到数据源实例对象中。
2 根据创建的数据源，配置数据库实例对象注入到 SqlSessionFactory 中，构建对应的 SqlSessionFactory。
3 配置数据库事务：将数据源添加到事务中。
4 将 SqlSessionFactory 注入到 SqlSessionTemplate 模板中
5 最后将上面创建的 SqlSessionTemplate 注入到对应的 Mapper 包路径下，这样这个包下面的 Mapper 都会使用第一个数据源来进行数据库操作。

basePackages   指明 Mapper 地址。sqlSessionTemplateRef    指定 Mapper 路径下注入的 sqlSessionTemplate。

在多数据源的情况下，不需要在启动类添加：@MapperScan(“com.xxx.mapper”) 的注解。

2 项目结构：

3 第一个数据源

@Api("SqlSessionTemplate 注入到对应的 Mapper 包路径下")
@Configuration
@MapperScan(basePackages = "com.example.demo.mapper.one", sqlSessionTemplateRef  = "oneSqlSessionTemplate")
public class OneDataSourceConfig {

    //------------------                 1 加载配置的数据源：-------------------------------
    @Bean("oneDatasource")
    @ConfigurationProperties(prefix = "spring.datasource.one")
    @Primary // 默认是这个库
    public DataSource DataSource1Config(){return DataSourceBuilder.create().build();}





    //---------------------- 2 创建的数据源 构建对应的 SqlSessionFactory。----------------------

    @Bean(name = "oneSqlSessionFactory")
    @Primary
    public SqlSessionFactory oneSqlSessionFactory(@Qualifier("oneDatasource") DataSource dataSource) throws Exception {SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:/mapper/one/*.xml"));
        return bean.getObject();}


    //------------------------3  配置事务 --------------------------
    @Bean(name = "oneTransactionManager")
    @Primary
    public DataSourceTransactionManager oneTransactionManager(@Qualifier("oneDatasource") DataSource dataSource) {return new DataSourceTransactionManager(dataSource);
    }



    //------------------------------- 4 注入 SqlSessionFactory 到 SqlSessionTemplate 中 ---------------------------------
    @Bean(name = "oneSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate oneSqlSessionTemplate(@Qualifier("oneSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {return new SqlSessionTemplate(sqlSessionFactory);
    }

}

第二个数据源

@Api("SqlSessionTemplate 注入到对应的 Mapper 包路径下")
@Configuration
@MapperScan(basePackages = "com.example.demo.mapper.second", sqlSessionTemplateRef  = "secondSqlSessionTemplate")
public class SecondDataSourceConfig {


    //------------------                  加载配置的数据源：-------------------------------


    @Bean("secondDatasource")
    @ConfigurationProperties(prefix = "spring.datasource.second")
    public DataSource DataSource2Config(){return DataSourceBuilder.create().build();}





    //---------------------- 创建的数据源 构建对应的 SqlSessionFactory。----------------------



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

    //------------------------ 配置事务 --------------------------


    @Bean(name = "secondTransactionManager")
    public DataSourceTransactionManager secondTransactionManager(@Qualifier("secondDatasource") DataSource dataSource) {return new DataSourceTransactionManager(dataSource);
    }


    //------------------------------- 注入 SqlSessionFactory 到 SqlSessionTemplate 中 ---------------------------------


    @Bean(name = "secondSqlSessionTemplate")
    public SqlSessionTemplate secondSqlSessionTemplate(@Qualifier("secondSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {return new SqlSessionTemplate(sqlSessionFactory);
    }

}

3 xml 文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
</configuration>

4 mapper 类

public interface User1Mapper {public void inserts(User user);
}

public interface User2Mapper {public void inserts(User user);
}

5 mybatis mapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">


<mapper namespace="com.example.demo.mapper.one.User1Mapper">
    <insert id="inserts" parameterType="com.example.demo.pojo.User" useGeneratedKeys="true" keyProperty="id">
        insert into user(`name`,age) VALUE (#{name},#{age})
    </insert>
  
</mapper>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">


<mapper namespace="com.example.demo.mapper.one.User2Mapper">
    <insert id="inserts" parameterType="com.example.demo.pojo.User" useGeneratedKeys="true" keyProperty="id">
        insert into user(`name`,age) VALUE (#{name},#{age})
    </insert>
  
</mapper>

3 启动成功

表示数据源创建成功，这里连接池采用 springboot 默认的 Hikari 数据库连接池 (不需要配置)

6 测试

    @Autowired
    User1Mapper user1Mapper;

    @Autowired
    User2Mapper user2Mapper;
    @Test
    public void test(){user1Mapper.inserts(new User(22L, "a123456",1));
        user1Mapper.inserts(new User(33L, "b123456", 1));
        user2Mapper.inserts(new User(44L, "b123456", 1));
    }

结果

7 更换数据源配置

官方文档：https://github.com/alibaba/dr…

增加配置文件 , 更换为 durid 数据源

1 配置文件增加配置属性

#  StatViewServlet 配置
spring.datasource.druid.stat-view-servlet.login-username=admin
spring.datasource.druid.stat-view-servlet.login-password=admin

# 配置 StatFilter
spring.datasource.druid.filter.stat.log-slow-sql=true
spring.datasource.druid.filter.stat.slow-sql-millis=2000

# Druid 数据源 1 配置
spring.datasource.druid.one.initial-size=3
spring.datasource.druid.one.min-idle=3
spring.datasource.druid.one.max-active=10
spring.datasource.druid.one.max-wait=60000

# Druid 数据源 2 配置
spring.datasource.druid.second.initial-size=6
spring.datasource.druid.second.min-idle=6
spring.datasource.druid.second.max-active=20
spring.datasource.druid.second.max-wait=120000

将上面数据库配置文件前缀加上 druid

如：

#  StatViewServlet 配置
spring.datasource.druid.stat-view-servlet.login-username=admin
spring.datasource.druid.stat-view-servlet.login-password=admin

# 配置 StatFilter
spring.datasource.druid.filter.stat.log-slow-sql=true
spring.datasource.druid.filter.stat.slow-sql-millis=2000

# Druid 数据源 1 配置
spring.datasource.druid.one.initial-size=3
spring.datasource.druid.one.min-idle=3
spring.datasource.druid.one.max-active=10
spring.datasource.druid.one.max-wait=60000

# Druid 数据源 2 配置
spring.datasource.druid.second.initial-size=6
spring.datasource.druid.second.min-idle=6
spring.datasource.druid.second.max-active=20
spring.datasource.druid.second.max-wait=120000

#mybatis.type-aliases-package = com.example.demo.pojo
#################  mysql  数据源 1 #################
spring.datasource.druid.one.url=jdbc:mysql://localhost:3306/user?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.druid.one.username=root
spring.datasource.druid.one.password=root
spring.datasource.druid.one.driver-class-name=com.mysql.jdbc.Driver
#################  mysql  数据源 1 #################

#################  mysql  数据源 2 #################
spring.datasource.druid.second.url=jdbc:mysql://xxxxxxxxxxx:3306/user?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.druid.second.username=root
spring.datasource.druid.second.password=root
spring.datasource.druid.second.driver-class-name=com.mysql.jdbc.Driver
#################  mysql  数据源 1 #################

2 引入依赖

    <!--druid-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>

然后在加载数据源配置哪儿读取配置文件注解改为

@ConfigurationProperties(prefix = "spring.datasource.druid.one")
@ConfigurationProperties(prefix = "spring.datasource.druid.second")

启动后发现配置成功

过程中可能会遇到问题

Failed to configure a DataSource: ‘url’ attribute is not specified and no embedded datasource could be configured.
Reason: Failed to determine a suitable driver class

原因是：url 链接写错了 , SpringBoot duridd 无法配置到 数据源 url

 错误：spring.datasource.druid.one.jdbc-url=jdbc:mysql://localhost:3306/user?   这是 jdbc 的 url 链接

正确：spring.datasource.druid.one.url=jdbc:mysql://localhost:3306/user?   这是连接池用的 url