大數據

如何區分多數據源?

本文來自於千鋒教育在阿里雲開發者社區學習中心上線課程《SpringBoot實戰教程》,主講人楊紅豔,點擊查看視頻內容

SpringBoot區分多數據源

在項目中,我們通常會進行數據庫拆分或是引入其他數據庫,從而我們需要配置多個數據源。

如何區分多個數據源:

  1. 通過包來區分:com.db1.mapper、com.db2.mapper
  2. 使用註解來區分:需要用到大量的註解,一般不推薦使用。

如何通過包名來區分多數據源

使用MySQL數據庫,框架是Mybatis。
在工程中導入依賴:

<!-- springboot集成mybatis -->
      <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>
    
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

在全局配置文件application.properties配置數據源

#SpringBoot整合多數據源
spring.datasource.db1.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.db1.username=root
spring.datasource.db1.password=root
spring.datasource.db1.url=jdbc:mysql://localhost:3306/db1

spring.datasource.db5.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.db5.username=root
spring.datasource.db5.password=root
spring.datasource.db5.url=jdbc:mysql://localhost:3306/db5

為每個數據源進行配置:
新建包com.qianfeng.datasource,新建類DataSource1

@Configuration//註冊到Spring容器中
@MapperScan(basePackages="com.qianfeng.db1.mapper",sqlSessionFactoryRef="db1SqlSessionFactory")
public class DataSource1 {
    
    //private DataSource1(){}

    /**
     * 配置db1數據庫
     * @return
     */
    @Bean(name="db1Datasource")
    @ConfigurationProperties(prefix="spring.datasource.db1")
    @Primary    //指定默認的數據源
    public DataSource testDatasource() {
        return DataSourceBuilder.create().build();
    }
    /**
     * 創建SqlSessionFactory
     * @param dataSource
     * @return
     * @throws Exception
     */
    @Bean(name="db1SqlSessionFactory")
    @Primary
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("db1Datasource")DataSource dataSource) 
            throws Exception {
        SqlSessionFactoryBean bean=new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        return bean.getObject();
    }
    /**
     * 配置事務管理
     * @param dataSource
     * @return
     */
    @Bean(name="db1TransactionManager")
    @Primary
    public DataSourceTransactionManager testTransactionManager(
            @Qualifier("db1Datasource")DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
 
    @Bean(name="db1SqlSessionTemplate")
    @Primary
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("db1SqlSessionFactory")
    SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

新建類DataSource2:

@Configuration
@MapperScan(basePackages="com.qianfeng.db5.mapper",sqlSessionFactoryRef="db5SqlSessionFactory")
public class DataSource2 {

    /**
     * 配置db5數據庫
     * @return
     */
    @Bean(name="db5Datasource")
    @ConfigurationProperties(prefix="spring.datasource.db5")
    public DataSource testDatasource() {
        return DataSourceBuilder.create().build();
    }
    /**
     * 創建SqlSessionFactory
     * @param dataSource
     * @return
     * @throws Exception
     */
    @Bean(name="db5SqlSessionFactory")
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("db5Datasource")DataSource dataSource) 
            throws Exception {
        SqlSessionFactoryBean bean=new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        //如果還有分頁等其他事務
//      bean.setMapperLocations(new PathMatchingResourcePatternResolver().
//              getResources("classpath:mybatis/test1/*.xml"));
        return bean.getObject();
    }
    /**
     * 配置事務管理
     * @param dataSource
     * @return
     */
    @Bean(name="db5TransactionManager")
    public DataSourceTransactionManager testTransactionManager(
            @Qualifier("db5Datasource")DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
 
    @Bean(name="db5SqlSessionTemplate")
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("db5SqlSessionFactory")
    SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

新建包:com.qianfeng.pojo,逆向生成user實體類和users實體類

新建包:com.qianfeng.db1.mapper,以users表為例

UsersMapper:

@Qualifier("db1SqlSessionFactory")
public interface UsersMapper {

    @Insert("insert into users(name, password) values(#{name}, #{password})")    
    void addUser(@Param("name") String name, @Param("password")String password);
}

新建包:com.qianfeng.db1.service

public interface UsersService {

    void saveUser(Users user);
}

UsersServiceImpl:

@Service
public class UsersServiceImpl implements UsersService {

    @Autowired
    private UsersMapper usersMapper;

    @Override
    public void saveUser(Users user) {
        usersMapper.addUser(user.getName(), user.getPassword());
    }

}

新建包:com.qianfeng.db5.mapper,以user表為例

UserMapper:

@Qualifier("db5SqlSessionFactory")
public interface UserMapper {

    @Insert("insert into user(username, birthday) values(#{username}, #{birthday})")    
    void addUser(@Param("username") String username, @Param("birthday")Date birthday);
}

新建包:com.qianfeng.db5.service

public interface UserService {

    void saveUser(User user);
}

UserServiceImpl:

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public void saveUser(User user) {
        userMapper.addUser(user.getUsername(), user.getBirthday());
    }

}

新建包:com.qianfeng.controller

@Controller
public class IndexController {

    @Autowired
    private UsersService usersService;

    @Autowired
    private UserService userService;

   @RequestMapping("/addUser")
    @ResponseBody
    public String addUser() {

        Users u = new Users();
        u.setName("lisi");
        u.setPassword("000000");

        usersService.saveUser(u);
        return "ok";
    }
}

在啟動類中添加所有需要掃描的包:

@SpringBootApplication(scanBasePackages="com.qianfeng")

mapper在配置數據源是已經掃描過,所以可以不掃描。

訪問IndexController,執行結果:
image.png
image.png

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