springboot+mybatis多数据源配置

1、前言

2、多数据源配置

2.1 AbstractRoutingDataSource

2.2、首先maven依赖

2.3 数据源配置

2.4 mybatis配置

2.5 设置数据源的路由key 以及查找数据源

3、切面拦截

3.1 定义切面注解

3.2 切面实现类

4、测试Controller

1、前言

在最近的项目开发中，有需要把多个服务整合，涉及到了多个数据库访问。所以记录一下多数据源的配置。在我自己的项目中，JDK使用的是1.8版本，SpringBoot是1.5.21版本。

2、多数据源配置

2.1 AbstractRoutingDataSource

动态数据源的配置是基于key路由到特定的数据源，由路由key与目标数据源产生映射关系。springboot提供了一个抽象类AbstractRoutingDataSource来实现，我们只需要实现determineCurrentLookupKey方法即可。

2.2、首先maven依赖

 <parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.5.21.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>${fastjson.version}</version></dependency><!-- spring集成热部署 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-devtools</artifactId><optional>true</optional></dependency><!-- spring集成配置文件的操作组件 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-configuration-processor</artifactId><optional>true</optional></dependency><!-- druid连接池监控 --><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>${druid.version}</version></dependency><!-- jdbc连接驱动 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.0.1</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-aop</artifactId></dependency><dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId></dependency><!--reflectasm使用字节码生成的方式实现了更为高效的反射机制 --><dependency><groupId>com.esotericsoftware</groupId><artifactId>reflectasm</artifactId><version>1.11.9</version></dependency><!-- redis使用 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency><dependency><groupId>commons-lang</groupId><artifactId>commons-lang</artifactId><version>2.6</version></dependency><dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpclient</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-mongodb</artifactId></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><configuration><source>1.8</source><target>1.8</target></configuration></plugin></plugins><defaultGoal>compile</defaultGoal></build>

2.3 数据源配置

application.yml配置

spring:datasource:user:driverClassName: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://192.168.1.15:3306/test_user?serverTimezone=Asia/Shanghai&allowMultiQueries=true&useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghaiusername: rootpassword: rootpatient:driverClassName: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://192.168.1.15:3306/test_patient?serverTimezone=Asia/Shanghai&allowMultiQueries=true&useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghaiusername: rootpassword: rootdoctor:driverClassName: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://192.168.1.15:3306/test_doctor?serverTimezone=Asia/Shanghai&allowMultiQueries=true&useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghaiusername: rootpassword: rootdruid:initialSize: 5minIdle: 5maxActive: 20maxWait: 60000timeBetweenEvictionRunsMillis: 60000minEvictableIdleTimeMillis: 300000validationQuery: SELECT 1 FROM DUALtestWhileIdle: truetestOnBorrow: falsetestOnReturn: false poolPreparedStatements: truemaxPoolPreparedStatementPerConnectionSize: 20filters: stat,log4jconnectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000

多数据源配置类

import java.util.HashMap;
import java.util.Map;import javax.sql.DataSource;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.env.Environment;
import com.alibaba.druid.pool.DruidDataSourceFactory;/***   动态数据源配置* @author LongBJ**/
@Configuration
@MapperScan("com.kingseok.hospital.business.*.dao")
public class DynamicDataSourceConfig implements EnvironmentAware {/***  user数据源* * @return*/@Bean@ConfigurationProperties(prefix = "spring.datasource.user")public DataSource userDataSource() {//DruidDataSourceFactory.createDataSource(properties);return DataSourceBuilder.create().build();}/***     patient数据源* @return*/@Bean@ConfigurationProperties(prefix = "spring.datasource.patient")public DataSource patientDataSource() {return DataSourceBuilder.create().build();}/***    doctor数据源* @return*/@Bean@ConfigurationProperties(prefix = "spring.datasource.doctor")public DataSource doctorDataSource() {return DataSourceBuilder.create().build();}/***   配置动态数据源* * @return*/@Primary // 此处指定动态数据源为primary@Bean(name = "dynamicDataSource")public DataSource dynamicDataSource(@Qualifier("userDataSource") DataSource userDataSource,@Qualifier("patientDataSource") DataSource patientDataSource, @Qualifier("doctorDataSource") DataSource doctorDataSource) {Map<Object, Object> dataSourceMap = new HashMap<>(3);dataSourceMap.put(DataSourceEnum.DS_USER.getValue(), userDataSource);dataSourceMap.put(DataSourceEnum.DS_PATIENT.getValue(), patientDataSource);dataSourceMap.put(DataSourceEnum.DS_DOCTOR.getValue(), doctorDataSource);DynamicDataSource dynamicDataSource = new DynamicDataSource();dynamicDataSource.setTargetDataSources(dataSourceMap);dynamicDataSource.setDefaultTargetDataSource(userDataSource); // 指定默认的数据源return dynamicDataSource;}@Autowiredprivate Environment env;@Overridepublic void setEnvironment(Environment environment) {this.env = environment;}}

此处配置了4个数据源，分别是user、patient、doctor，还有一个路由数据源。前面3个是为了生成第4个数据源，这个是动态数据源的关键，后面的数据源切换也是从这里选择。

2.4 mybatis配置

import javax.annotation.Resource;
import javax.sql.DataSource;import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;/**
**   Mybatis配置
**/
@Configuration
@EnableTransactionManagement
public class MyBatisConfig {@Resource(name = "dynamicDataSource")private DataSource dynamicDataSource;/*** sqlSessionFactory* @return* @throws Exception*/@Beanpublic SqlSessionFactory sqlSessionFactory() throws Exception {SqlSessionFactoryBean factory = new SqlSessionFactoryBean();factory.setDataSource(dynamicDataSource);PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();factory.setMapperLocations(resolver.getResources("classpath:mapper/**/*.xml"));return factory.getObject();}@Beanpublic SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {return new SqlSessionTemplate(sqlSessionFactory);}/*** 事务管理器* @return*/@Beanpublic PlatformTransactionManager platformTransactionManager() {return new DataSourceTransactionManager(dynamicDataSource); }
}

由于我们是多数据源，所以我们要为事务管理器和mybatis手动指定明确的数据源。

2.5 设置数据源的路由key 以及查找数据源

首先我们定义一个数据源枚举（常量类也行），如下：

public enum DataSourceEnum {DS_USER("DS_USER", "user数据源"),DS_PATIENT("DS_PATIENT", "patient数据源"),DS_DOCTOR("DS_DOCTOR","doctor数据源"),DS_KUAIMA_MEDICAL("medical", "medical数据源"),DS_PDD_IM("pdd_im_data", "im数据源");private String value;private String display;DataSourceEnum(String value, String display) {this.value = value;this.display = display;}public String getValue() {return value;}public void setValue(String value) {this.value = value;}public String getDisplay() {return display;}public void setDisplay(String display) {this.display = display;}
}

接下来，我们利用ThreadLocal将数据源设置到每个请求的线程上下文当中，代码如下：

/**
** 动态数据源线程上下文操作类
**/
public class DynamicDataSourceContextHolder {private final static ThreadLocal<String> DATASOURCE_CONTEXT_KEY_HOLDER = new ThreadLocal<>();/*** 设置/切换数据源*/public static void setContextKey(String key){DATASOURCE_CONTEXT_KEY_HOLDER.set(key);}/*** 获取数据源名称*/public static String getContextKey(){String key = DATASOURCE_CONTEXT_KEY_HOLDER.get();return key == null ? DataSourceEnum.DS_USER.getValue() : key;}/*** 删除当前数据源名称*/public static void removeContextKey(){DATASOURCE_CONTEXT_KEY_HOLDER.remove();}}

前面说过动态数据源选择，springboot提供的抽象类AbstractRoutingDataSource提供了一个方法，我们实现这个方法即可，所以我们创建一个动态数据源选择类，然后继承AbstractRoutingDataSource，如下：

/***     动态数据源选择* @author LongBJ**/
public class DynamicDataSource extends AbstractRoutingDataSource {@Overrideprotected Object determineCurrentLookupKey() {// 前面将用户请求的数据源路由key set到threadLocal, 此处从ThreadLocal获取出来，// 拿到key之后，找到对应的数据源（key就是DynamicDataSourceConfig类中配置的key）return DynamicDataSourceContextHolder.getContextKey();}}

至此，多数据源便已完全配置，接下来就是如何识别用户的访问哪一个数据源，我自己的项目是通过AOP切面来实现的。

3、切面拦截

3.1 定义切面注解

定义一个切面注解用于访问的类或者方法上，如下：

import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.ElementType.METHOD;import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;import com.kingseok.hospital.common.configuration.DataSourceEnum;@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ TYPE, METHOD })   // TYPE可用户类上，METHOD用于请求方法上
public @interface SqlDynamicDS {DataSourceEnum value() default DataSourceEnum.DS_USER;}

3.2 切面实现类

有了切面注解，还需要实现切面拦截，实现非常简单，只需要定义一个类，在类上使用@Aspect和@Component即可实现。

/***     mysql动态数据源切面* @author LongBJ**/
@Aspect
@Component
@Order(value = Ordered.HIGHEST_PRECEDENCE)
public class DynamicDatasourceAspect {private final static Logger _logger = LoggerFactory.getLogger(DynamicDatasourceAspect.class);@Pointcut("@within(com.kingseok.hospital.common.annotation.SqlDynamicDS)")public void dataSourcePointCut() {}@Pointcut("@annotation(com.kingseok.hospital.common.annotation.SqlDynamicDS)")public void dataSourcePointCut2() {}@Around("dataSourcePointCut() || dataSourcePointCut2()")public Object getSqlDynamicDS(ProceedingJoinPoint joinPoint) throws Throwable {DataSourceEnum ds = getDSAnnocation(joinPoint).value();_logger.info("DynamicDatasourceAspect : getSqlDynamicDS -> ds_key={}", ds.getValue());DynamicDataSourceContextHolder.setContextKey(ds.getValue());try{return joinPoint.proceed();}finally {DynamicDataSourceContextHolder.removeContextKey();_logger.info("DynamicDatasourceAspect : getSqlDynamicDS -> ThreadLocal已删除ds_key={}", ds.getValue());} }private SqlDynamicDS getDSAnnocation(ProceedingJoinPoint joinPoint) {Class<?> targetClazz = joinPoint.getTarget().getClass();SqlDynamicDS ds = targetClazz.getAnnotation(SqlDynamicDS.class);//    先判断类的注解，再判断方法注解if(Objects.nonNull(ds)) {return ds;}MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();return methodSignature.getMethod().getAnnotation(SqlDynamicDS.class);}}

这里需要特别注意，我定义了2个切面。为什么定义2个，有眼尖的同学会发现@Pointcut("@within(com.kingseok.hospital.common.annotation.SqlDynamicDS)")和@Pointcut("@annotation(com.kingseok.hospital.common.annotation.SqlDynamicDS)")仅仅是@within和@annotation不同，其实@within：用于匹配所持有的指定直接类型内的所有方法；而@annotation：用于配置当前执行方法持有指定注解的方法。参考如下：

4、测试Controller

import com.cjs.example.entity.Member;
import com.cjs.example.service.MemberService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;@RunWith(SpringRunner.class)
@SpringBootTest
@SqlDynamicDS(value = DataSourceEnum.DS_USER) // 作用于类上，则此类所有方法请求都将路由到数据源DataSourceEnum.DS_USER上  类的优先级高于方法
public class DatasourceDemoApplicationTests {@Autowiredprivate MemberService memberService;@Testpublic void testWrite() {Member member = new Member();member.setName("zhangsan");memberService.insert(member);}@Test@SqlDynamicDS(value = DataSourceEnum.DS_USER) // 作用于方法上public void testReadFromMaster() {memberService.getUser("zhangsan");}}

至此，这个多数据源配置已完成