springboot+mybatis实现动态切换数据源

Posted 2020-11-16 Ruthless

目前有个需求，需要使用不同的数据源，例如某业务要用A数据源，另一个业务要用B数据源。

使用springboot 整合多数据源 遇到的坑

1、添加依赖

<!-- 阿里的druid 依赖log4j -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.0</version>
</dependency>
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.4.1</version>
</dependency>

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>

<!-- 引入mybatis-spring -->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>1.3.1</version>
</dependency>

 

2、application.properties配置文件

#主数据库
master:
  db:
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://47.111.22.159:3306/xinyar_erp_uat?useUnicode=true&characterEncoding=utf-8&allowMultiQueries=true&useSSL=false
    username: erp_test
    password: erp_test@abc

#从数据库    
slave:
  db:
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://47.111.22.159:3306/erp-test?useUnicode=true&characterEncoding=utf-8&allowMultiQueries=true&useSSL=false
    username: erp_test
    password: erp_test@abc

mybatis:
  mapper-locations: classpath*:com/xinyartech/erp/*/xml/*/*.xml
  type-aliases-package: com.xinyartech.erp.*.model,com.xinyartech.erp.*.vo
  configuration: 
    map-underscore-to-camel-case: true

 

3、禁用springboot默认加载数据源配置

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class Application {
    
    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);
    }
}

 

4、主数据源配置类

import org.springframework.boot.context.properties.ConfigurationProperties;

import org.springframework.context.annotation.Configuration;

import lombok.Data;
import org.springframework.beans.factory.annotation.Value;

/**
 * 主数据源
 * 
 * @author Lynch
 *
 */
@Configuration
@ConfigurationProperties(prefix = "master.db")
@Data
public class MasterDataSourceConfig {
    @Value("${master.db.url}")
    private String url;
    @Value("${master.db.username}")
    private String username;
    @Value("${master.db.password}")
    private String password;
    @Value("${master.db.driverClassName}")
    private String driverClassName;
}

 

5、从数据源配置类

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

import lombok.Data;

/**
 * 从数据源
 * 
 * @author Lynch
 *
 */
@Configuration
@ConfigurationProperties(prefix = "slave.db")
@Data
public class SlaveDataSourceConfig {
    @Value("${slave.db.url}")
    private String url;
    @Value("${slave.db.username}")
    private String username;
    @Value("${slave.db.password}")
    private String password;
    @Value("${slave.db.driverClassName}")
    private String driverClassName;
}

 

6、数据源配置类

import java.util.HashMap;
import java.util.Map;

import javax.annotation.Resource;
import javax.sql.DataSource;

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;
import org.springframework.context.annotation.Primary;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;

/**
 * 数据源配置类
 *
 * @author Lynch
 */
@Configuration
public class DataSourceComponent {
    @Resource
    private MasterDataSourceConfig masterDataSourceConfig;
    @Resource
    private SlaveDataSourceConfig slaveDataSourceConfig;

    @Bean(name = "master")
    public DataSource masterDataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl(masterDataSourceConfig.getUrl());
        dataSource.setUsername(masterDataSourceConfig.getUsername());
        dataSource.setPassword(masterDataSourceConfig.getPassword());
        dataSource.setDriverClassName(masterDataSourceConfig.getDriverClassName());
        return dataSource;
    }

    @Bean(name = "slave")
    public DataSource slaveDataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl(slaveDataSourceConfig.getUrl());
        dataSource.setUsername(slaveDataSourceConfig.getUsername());
        dataSource.setPassword(slaveDataSourceConfig.getPassword());
        dataSource.setDriverClassName(slaveDataSourceConfig.getDriverClassName());
        return dataSource;
    }

    @Primary//不加这个会报错。
    @DependsOn({ "master", "slave"}) //解决数据库循环依赖问题
    @Bean(name = "multiDataSource")
    public MultiRouteDataSource exampleRouteDataSource() {
        MultiRouteDataSource multiDataSource = new MultiRouteDataSource();
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put("master", masterDataSource());
        targetDataSources.put("slave", slaveDataSource());
        multiDataSource.setTargetDataSources(targetDataSources);
        multiDataSource.setDefaultTargetDataSource(masterDataSource());
        return multiDataSource;
    }

    /**
     * 注册ServletRegistrationBean
     * 
     * @return
     */
    @Bean
    public ServletRegistrationBean druidServlet() {
        ServletRegistrationBean reg = new ServletRegistrationBean();
        reg.setServlet(new StatViewServlet());
        reg.addUrlMappings("/druid/*");
        reg.addInitParameter("allow", ""); // 白名单 return reg;
        reg.addInitParameter("loginUsername", "duan");
        reg.addInitParameter("loginPassword", "123456");
        reg.addInitParameter("resetEnable", "false");
        return reg;
    }

    /**
     * 注册FilterRegistrationBean
     * 
     * @return
     */
    @Bean
    public FilterRegistrationBean filterRegistrationBean() {
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(new WebStatFilter());
        filterRegistrationBean.addUrlPatterns("/*");
        filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
        filterRegistrationBean.addInitParameter("profileEnable", "true");
        filterRegistrationBean.addInitParameter("principalCookieName", "USER_COOKIE");
        filterRegistrationBean.addInitParameter("principalSessionName", "USER_SESSION");
        filterRegistrationBean.addInitParameter("DruidWebStatFilter", "/*");
        return filterRegistrationBean;
    }
}

 

7、数据源上下文

/**
 * 数据源上下文
 *
 * @author Lynch
 */
public class DataSourceContext {
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

    public static void setDataSource(String value) {
        contextHolder.set(value);
    }

    public static String getDataSource() {
        return contextHolder.get();
    }

    public static void clearDataSource() {
        contextHolder.remove();
    }
}

 

8、DataSource路由类

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

import com.xinyartech.erp.config.DataSourceContext;

/**
 * DataSource路由类
 * 
 * 重写的函数决定了最后选择的DataSource
 *
 * @author Lynch
 */
public class MultiRouteDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        // 通过绑定线程的数据源上下文实现多数据源的动态切换,有兴趣的可以去查阅资料或源码
        return DataSourceContext.getDataSource();
    }
}

 

9、修改上下文中的数据源就可以切换自己想要使用的数据源了 

public UserVO findUser(String username) {
    DataSourceContext.setDataSource("slave");
    UserVO userVO = userMapper.findByVO(username);
    System.out.println(userVO.getName());
    return null;
}

这种是在业务中使用代码设置数据源的方式，也可以使用AOP+注解的方式实现控制，还可以前端头部设置后端通过拦截器统一设置！