springboot-mybatis多数据配置

在我们项目访问人数比较多，数据量比较大的情况下，我们可能需要使用多数据源的情况，将一部分数据放到另一个数据库中，比如数据库主从同步，我们项目可以写主库，读从库，降低单个数据库的压力，提高程序的性能。接下来简单搭建一下springboot+mybatis的多数据环境。

目的

在同一个项目中集成两个数据源，可以通过程序控制指定访问的数据库。

环境

框架：springboot+mybatis
数据库：mysql
连接池：Druid

搭建步骤

1、springboot+mybatis项目

项目结构如下图

pom.xml

<parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.0.5.RELEASE</version>
  </parent>
  <dependencies>
      <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
       <!-- 数据库操作 -->
      <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
     </dependency>
     <dependency>
          <groupId>org.mybatis.spring.boot</groupId>
          <artifactId>mybatis-spring-boot-starter</artifactId>
          <version>2.1.4</version>
     </dependency>
     <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.16</version>
    </dependency>
  </dependencies>

application.yml

###服务启动端口号
server:
  port: 80
spring:
  #durid
  datasource:
    one: 
      type: com.alibaba.druid.pool.DruidDataSource
      url: jdbc:mysql://192.168.157.6:3306/test?useSSL=false
      #开发环境
      username: root
      password: 123456
      driverClassName: com.mysql.jdbc.Driver
      #连接池的配置信息
      initialSize: 5
      minIdle: 5
      maxActive: 20
      maxWait: 60000
      timeBetweenEvictionRunsMillis: 60000
      minEvictableIdleTimeMillis: 300000
      validationQuery: SELECT 1 FROM DUAL
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20
    two: 
      type: com.alibaba.druid.pool.DruidDataSource
      url: jdbc:mysql://192.168.157.7:3306/test?useSSL=false
      username: root
      password: 123456
      driverClassName: com.mysql.jdbc.Driver
      #连接池的配置信息
      initialSize: 5
      minIdle: 5
      maxActive: 20
      maxWait: 60000
      timeBetweenEvictionRunsMillis: 60000
      minEvictableIdleTimeMillis: 300000
      validationQuery: SELECT 1 FROM DUAL
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20

上面是用one和two来区分两个数据源，一个是192.168.157.6服务器一个是192.168.157.7服务器

2、DataSourcesConfig.java

spring容器中建立DataSource

@Configuration
public class DataSourcesConfig {
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.one")
    DataSource dsOne(){
        return DruidDataSourceBuilder.create().build();
    }
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.two")
    DataSource dsTwo(){
        return DruidDataSourceBuilder.create().build();
    }
}

3、MyBatisConfigOne.java

@Configuration
@MapperScan(basePackages = "com.suibibk.mapper.mapper1",
sqlSessionFactoryRef = "sqlSessionFactory1",
sqlSessionTemplateRef = "sqlSessionTemplate1")
public class MyBatisConfigOne {
    @Resource
    DataSource dsOne;
    @Bean
    SqlSessionFactory sqlSessionFactory1()throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dsOne);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().
                getResources("classpath:mapper/mapper1/*.xml"));
        return bean.getObject();
    }
    @Bean
    SqlSessionTemplate sqlSessionTemplate1() throws Exception{
        return new SqlSessionTemplate(sqlSessionFactory1());
    }
}

指定了扫包路径以及xml路径，当然如果是将sql直接写在mapper里面，不用xml配置文件的话可以不指定内容

bean.setMapperLocations(new PathMatchingResourcePatternResolver().
                getResources("classpath:mapper/mapper1/*.xml"));

4、MyBatisConfigTwo.java

@Configuration
@MapperScan(basePackages = "com.suibibk.mapper.mapper2",
sqlSessionFactoryRef = "sqlSessionFactory2",
sqlSessionTemplateRef = "sqlSessionTemplate2")
public class MyBatisConfigTwo {
    @Resource
    DataSource dsTwo;
    @Bean
    SqlSessionFactory sqlSessionFactory2()throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dsTwo);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().
                getResources("classpath:mapper/mapper2/*.xml"));
        return bean.getObject();
    }
    @Bean
    SqlSessionTemplate sqlSessionTemplate2() throws Exception{
        return new SqlSessionTemplate(sqlSessionFactory2());
    }
}

5、UserMapper1.java

public interface UserMapper1 {
    //@Select("select * from user")
    List<User> getUsers();
}

6、UserMapper2.java

public interface UserMapper2 {
    //@Select("select * from user")
    List<User> getUsers();
}

如果在这里面写sql的话，那么MyBatisConfig就不需要指定xml位置。

7、UserMapper1.xml

<mapper namespace="com.suibibk.mapper.mapper1.UserMapper1" >
    <select id="getUsers"  resultType="com.suibibk.entity.User">
        select * from user
    </select>
</mapper>

8、UserMapper2.xml

<mapper namespace="com.suibibk.mapper.mapper2.UserMapper2" >
    <select id="getUsers"  resultType="com.suibibk.entity.User">
        select * from user
    </select>
</mapper>

9、service

public interface UserService {
    List<User> getUsers1();
    List<User> getUsers2();
}
@Service
public class UserServiceImpl implements UserService{
    @Autowired
    UserMapper1 userMapper1;
    @Autowired
    UserMapper2 userMapper2;
    public List<User> getUsers1() {
        return userMapper1.getUsers();
    }
    public List<User> getUsers2() {
        return userMapper2.getUsers();
    }
}

10、controller

/**
 * http://localhost/test1 访问数据源1
 * http://localhost/test2 访问数据源2
 */
@Controller
public class TestController {
    @Autowired
    UserService userService;
    @ResponseBody
    @RequestMapping("/test1")
    public String test1() {
        List<User> users = userService.getUsers1();
        return users.toString();
    }
    @ResponseBody
    @RequestMapping("/test2")
    public String test2() {
        List<User> users = userService.getUsers2();
        return users.toString();
    }
}

11、User.java

public class User {
    private String name;
    private String passwd;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPasswd() {
        return passwd;
    }
    public void setPasswd(String passwd) {
        this.passwd = passwd;
    }
    @Override
    public String toString() {
        return "User [name=" + name + ", passwd=" + passwd + "]";
    }
}

12、启动App.java

@SpringBootApplication
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

测试

启动后访问

http://localhost/test1
http://localhost/test2

可以看到test1查询到的是192.168.157.6服务器数据库的数据，test2查询到的是192.168.157.7服务器的数据