目录

项目场景：

一、集成com.baomidou的方式

1、maven依赖：

2、 配置文件：

3、 使用注解切换数据源： 

二、基于AOP手动实现多数据源原生的方式

1、maven依赖：

2、 配置文件：

3、 多数据源名称类

4、自定义注解 

5、配置类

6、动态数据源配置

 7、AOP切面拦截注解

8、Dao层，跟正常一样的

 9、service层，加上多数据源注解

 10、Controller测试

三、结果展示

---

项目场景：

Spring Boot集成Druid实现多数据源的两种方式：

1、集成com.baomidou，引入dynamic-datasource依赖；

2、原生的方式，基于AOP手动实现多数据源；

---

一、集成com.baomidou的方式

1、maven依赖：

    com.baomidou
    dynamic-datasource-spring-boot-starter
    3.5.1


    com.alibaba
    druid-spring-boot-starter
    1.1.10

2、 配置文件：

1.spring.datasource.dynamic前缀，是baomidou源码里固定的；

2.first、second是自定义的名称，可以更改；

# 多数据源配置，默认master
spring.datasource.dynamic.primary = first
# 数据源1
spring.datasource.dynamic.datasource.first.driverClassName = com.mysql.cj.jdbc.Driver
spring.datasource.dynamic.datasource.first.type = com.alibaba.druid.pool.DruidDataSource
spring.datasource.dynamic.datasource.first.url = jdbc:mysql://127.0.0.1:3306/mp_dm?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
spring.datasource.dynamic.datasource.first.username = test
spring.datasource.dynamic.datasource.first.password = test1
# 数据源2
spring.datasource.dynamic.datasource.second.driverClassName = com.mysql.cj.jdbc.Driver
spring.datasource.dynamic.datasource.second.type = com.alibaba.druid.pool.DruidDataSource
spring.datasource.dynamic.datasource.second.url = jdbc:mysql://127.0.0.1:18306/mp_dm?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
spring.datasource.dynamic.datasource.second.username = test
spring.datasource.dynamic.datasource.second.password = test1
# druid多数据源全局配置
spring.datasource.dynamic.druid.filter.stat.log-slow-sql = true
spring.datasource.dynamic.druid.filter.stat.slow-sql-millis = 1000
spring.datasource.dynamic.druid.min-evictable-idle-time-millis = 300000
spring.datasource.dynamic.druid.test-on-borrow = false
spring.datasource.dynamic.druid.filter.stat.merge-sql = false
spring.datasource.dynamic.druid.test-on-return = false
spring.datasource.dynamic.druid.initial-size = 10
spring.datasource.dynamic.druid.min-idle = 10
spring.datasource.dynamic.druid.max-wait = 60000
spring.datasource.dynamic.druid.pool-prepared-statements = true
spring.datasource.dynamic.druid.test-while-idle = true
spring.datasource.dynamic.druid.validation-query = select 1
spring.datasource.dynamic.druid.filter.wall.config.multi-statement-allow = true
spring.datasource.dynamic.druid.time-between-eviction-runs-millis = 60000
spring.datasource.dynamic.druid.max-pool-prepared-statement-per-connection-size = 20
spring.datasource.dynamic.druid.max-active = 100
# druid监控全局配置
spring.datasource.druid.stat-view-servlet.enabled = true
spring.datasource.druid.stat-view-servlet.url-pattern = /druid/*

验证配置文件是否生效：Spring Boot集成Druid查看配置是否生效_涛哥是个大帅比的博客-CSDN博客 

3、 使用注解切换数据源： 

@DS注解说明：

1.注解在方法上、类上、接口、枚举，同时存在就近原则，方法上注解优先于类上注解；

2.不使用@DS注解，默认主数据源；

类上：

@DS("db2")
public class test(){}

 方法上：

@DS("db2")
public void test(){}

mapper方法上

@Select("SELECT * FROM TEST WHERE A = #{A}")
@DS("db2")
Map test(@Param("A") String A);

多数据源可能会碰到事务问题：

 Spring Boot多数据源事务@DSTransactional的使用_涛哥是个大帅比的博客-CSDN博客

---

二、基于AOP手动实现多数据源原生的方式

1、maven依赖：

    com.alibaba
    druid-spring-boot-starter
    1.1.10

2、 配置文件：

1.Spring Boot 2.X 版本不再支持配置继承，多数据源的话每个数据源的所有配置都需要单独配置，否则配置不会生效；

2.first、second是自定义的名称，对应DynamicDataSourceConfig配置类，可以更改；

# 多数据源配置
spring.datasource.type = com.alibaba.druid.pool.DruidDataSource
# 数据源1
spring.datasource.druid.first.name = first
spring.datasource.druid.first.driverClassName = com.mysql.cj.jdbc.Driver
spring.datasource.druid.first.url = jdbc:mysql://127.0.0.1:3306/mp_dm?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
spring.datasource.druid.first.username = test
spring.datasource.druid.first.password = test1
# 数据源2
spring.datasource.druid.second.name = second
spring.datasource.druid.second.driverClassName = com.mysql.cj.jdbc.Driver
spring.datasource.druid.second.url = jdbc:mysql://127.0.0.1:18306/mp_dm?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
spring.datasource.druid.second.username = test
spring.datasource.druid.second.password = test1
# druid数据源1
spring.datasource.druid.first.filter.stat.log-slow-sql = true
spring.datasource.druid.first.filter.stat.slow-sql-millis = 1000
spring.datasource.druid.first.min-evictable-idle-time-millis = 300000
spring.datasource.druid.test-on-borrow = false
spring.datasource.druid.first.filter.stat.merge-sql = false
spring.datasource.druid.test-on-return = false
spring.datasource.druid.first.initial-size = 10
spring.datasource.druid.first.min-idle = 10
spring.datasource.druid.first.max-wait = 60000
spring.datasource.druid.first.pool-prepared-statements = true
spring.datasource.druid.first.test-while-idle = true
spring.datasource.druid.first.validation-query = select 1
spring.datasource.druid.first.filter.wall.config.multi-statement-allow = true
spring.datasource.druid.first.time-between-eviction-runs-millis = 60000
spring.datasource.druid.first.max-pool-prepared-statement-per-connection-size = 20
spring.datasource.druid.first.max-active = 100
# druid数据源2
spring.datasource.druid.second.filter.stat.log-slow-sql = true
spring.datasource.druid.second.filter.stat.slow-sql-millis = 1000
spring.datasource.druid.second.min-evictable-idle-time-millis = 300000
spring.datasource.druid.second.test-on-borrow = false
spring.datasource.druid.second.filter.stat.merge-sql = false
spring.datasource.druid.second.test-on-return = false
spring.datasource.druid.second.initial-size = 10
spring.datasource.druid.second.min-idle = 10
spring.datasource.druid.second.max-wait = 60000
spring.datasource.druid.second.pool-prepared-statements = true
spring.datasource.druid.second.test-while-idle = true
spring.datasource.druid.second.validation-query = select 1
spring.datasource.druid.second.filter.wall.config.multi-statement-allow = true
spring.datasource.druid.second.time-between-eviction-runs-millis = 60000
spring.datasource.druid.second.max-pool-prepared-statement-per-connection-size = 20
spring.datasource.druid.second.max-active = 100
# druid监控全局配置
spring.datasource.druid.stat-view-servlet.enabled = true
spring.datasource.druid.stat-view-servlet.url-pattern = /druid/*

验证配置文件是否生效：Spring Boot集成Druid查看配置是否生效_涛哥是个大帅比的博客-CSDN博客 

3、 多数据源名称类

package com.test.datasources;
/**
 * 增加多数据源，在此配置
 */
public interface DataSourceNames {
    String FIRST = "first";
    String SECOND = "second";
} 

4、自定义注解 

package com.test.datasources.annotation;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
 * 多数据源注解
 */
//同时支持方法注解和类注解
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
    String value() default "";
}

5、配置类

package com.test.datasources;
import java.util.HashMap;
import java.util.Map;
import javax.sql.DataSource;
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.core.JdbcTemplate;
import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
/**
 * 配置多数据源
 */
@Configuration
public class DynamicDataSourceConfig {
    @Bean
    @ConfigurationProperties("spring.datasource.druid.first")
    public DataSource firstDataSource(){
        return DruidDataSourceBuilder.create().build();
    }
    @Bean
    @ConfigurationProperties("spring.datasource.druid.second")
    public DataSource secondDataSource(){
        return DruidDataSourceBuilder.create().build();
    }
    @Bean
    @Primary
    public DynamicDataSource dataSource(DataSource firstDataSource, DataSource secondDataSource) {
        Map targetDataSources = new HashMap<>();
        targetDataSources.put(DataSourceNames.FIRST, firstDataSource);
        targetDataSources.put(DataSourceNames.SECOND, secondDataSource);
        return new DynamicDataSource(firstDataSource, targetDataSources);
    }
    
    @Bean
    public JdbcTemplate jdbcTemplate() {
     return new JdbcTemplate(firstDataSource());
    }
}

6、动态数据源配置

package com.test.datasources;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
 * 动态数据源，关键代码
 */
public class DynamicDataSource extends AbstractRoutingDataSource {
    private static final ThreadLocal contextHolder = new ThreadLocal<>();
    public DynamicDataSource(DataSource defaultTargetDataSource, Map targetDataSources) {
        super.setDefaultTargetDataSource(defaultTargetDataSource);
        super.setTargetDataSources(targetDataSources);
        super.afterPropertiesSet();
    }
    @Override
    protected Object determineCurrentLookupKey() {
        return getDataSource();
    }
    public static void setDataSource(String dataSource) {
        contextHolder.set(dataSource);
    }
    public static String getDataSource() {
        return contextHolder.get();
    }
    public static void clearDataSource() {
        contextHolder.remove();
    }
}

 7、AOP切面拦截注解

package com.test.datasources.aspect;
import java.lang.reflect.Method;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;
import com.test.datasources.DataSourceNames;
import com.test.datasources.DynamicDataSource;
import com.test.datasources.annotation.DataSource;
/**
 * 多数据源，切面处理类
 */
@Aspect
@Component
public class DataSourceAspect implements Ordered {
    protected Logger logger = LoggerFactory.getLogger(getClass());
    /*
     * @annotation匹配指定注解的方法
     * @within匹配指定注解的类
     * 注意：这里只拦截所注解的类，如果调用的是父类的方法，那么不会拦截，除非父类方法在子类中被覆盖。
     */
    @Pointcut("@annotation(com.test.datasources.annotation.DataSource) || @within(com.test.datasources.annotation.DataSource)")
    public void dataSourcePointCut() {
    }
    @Around("dataSourcePointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();
        Class dataClass = Class.forName(signature.getDeclaringTypeName());
        
        DataSource dsMethod = method.getAnnotation(DataSource.class);
        DataSource dsClass = dataClass.getAnnotation(DataSource.class);
        if(dsMethod != null){
        	//方法优先，如果方法上存在注解，则优先使用方法上的注解
        	DynamicDataSource.setDataSource(dsMethod.value());
            logger.debug("set datasource is " + dsMethod.value());
        }else if(dsClass != null){
            //其次类优先，如果类上存在注解，则使用类上的注解
        	DynamicDataSource.setDataSource(dsClass.value());
            logger.debug("set datasource is " + dsClass.value());
        }else{
        	//如果都不存在，则使用默认
        	DynamicDataSource.setDataSource(DataSourceNames.FIRST);
            logger.debug("set datasource is " + DataSourceNames.FIRST);
        }
        try {
            return point.proceed();
        } finally {
            DynamicDataSource.clearDataSource();
            logger.debug("clean datasource");
        }
    }
    @Override
    public int getOrder() {
        return 1;
    }
}

8、Dao层，跟正常一样的

package com.test.mapper;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import com.test.entity.Test1Entity;
@Mapper
public interface Test1Dao {
	
	@Select("select * from test1")
	Test1Entity getById(@Param("id")Integer id);
}

package com.test.mapper;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import com.test.entity.Test2Entity;
@Mapper
public interface Test2Dao {
	@Select("select * from test2")
	Test2Entity getById(@Param("id")Integer id);
}

 9、service层，加上多数据源注解

package com.test.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.test.datasources.DataSourceNames;
import com.test.datasources.annotation.DataSource;
import com.test.entity.Test1Entity;
import com.test.mapper.Test1Dao;
@Service
@DataSource(DataSourceNames.FIRST)
public class Test1Service {
	@Autowired
	private Test1Dao test1Dao;
	
	public Test1Entity getById(int id) {
		return test1Dao.getById(id);
	}
}

package com.test.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.test.datasources.DataSourceNames;
import com.test.datasources.annotation.DataSource;
import com.test.entity.Test2Entity;
import com.test.mapper.Test2Dao;
@Service
@DataSource(DataSourceNames.SECOND)
public class Test2Service  {
	@Autowired
	private Test2Dao test2Dao;
	
	public Test2Entity getById(int id) {
		return test2Dao.getById(id);
	}
}

 10、Controller测试

package com.test.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import com.test.entity.Test1Entity;
import com.test.entity.Test2Entity;
import com.test.service.Test1Service;
import com.test.service.Test2Service;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
/**
 * 动态数据源测试
 */
@Api(tags = "动态数据源测试")
@RestController
@RequestMapping("/test")
public class DynamicController {
	@Autowired
	private Test1Service test1Service;
	@Autowired
	private Test2Service test2Service;
	
	@ApiOperation(value = "数据源1")
	@RequestMapping(value = "/test1", method = RequestMethod.GET)
	public String test1() {
		Test1Entity entity = test1Service.getById(1);
		return entity.getName();
	}
	
	@ApiOperation(value = "数据源2")
	@RequestMapping(value = "/test2", method = RequestMethod.GET)
	public String test2() {
		Test2Entity entity = test2Service.getById(2);
		return entity.getName();
	}
}

多数据源可能会碰到事务问题：https://blog.csdn.net/u011974797/article/details/130154340

三、结果展示

服务启动会打印日志：

com.alibaba.druid.pool.DruidDataSource   : {dataSource-1,first} inited
com.alibaba.druid.pool.DruidDataSource   : {dataSource-2,second} inited

druid监控页面：

 

源码地址：https://download.csdn.net/download/u011974797/87680942