在使用的过程中基本踩遍了所有动态数据源切换的坑，将常见的一些坑和解决方法写在了Issues 里面

添加依赖

dependencies {    compile('org.mybatis.spring.boot:mybatis-spring-boot-starter:1.3.2')    compile('org.springframework.boot:spring-boot-starter-web')    compile('org.springframework.boot:spring-boot-starter-aop')    runtime('mysql:mysql-connector-java')    testCompile('org.springframework.boot:spring-boot-starter-test')}

创建数据库及表

DROPDATABASE IF EXISTS product_master;CREATEDATABASEproduct_master;CREATETABLEproduct_master.product(  idINTPRIMARY KEY AUTO_INCREMENT,  nameVARCHAR(50)NOT NULL,  price DOUBLE(10,2)NOT NULL DEFAULT0);INSERT INTOproduct_master.product (name, price)VALUES('master','1');DROPDATABASE IF EXISTS product_slave_alpha;CREATEDATABASEproduct_slave_alpha;CREATETABLEproduct_slave_alpha.product(  idINTPRIMARY KEY AUTO_INCREMENT,  nameVARCHAR(50)NOT NULL,  price DOUBLE(10,2)NOT NULL DEFAULT0);INSERT INTOproduct_slave_alpha.product (name, price)VALUES('slaveAlpha','1');DROPDATABASE IF EXISTS product_slave_beta;CREATEDATABASEproduct_slave_beta;CREATETABLEproduct_slave_beta.product(  idINTPRIMARY KEY AUTO_INCREMENT,  nameVARCHAR(50)NOT NULL,  price DOUBLE(10,2)NOT NULL DEFAULT0);INSERT INTOproduct_slave_beta.product (name, price)VALUES('slaveBeta','1');DROPDATABASE IF EXISTS product_slave_gamma;CREATEDATABASEproduct_slave_gamma;CREATETABLEproduct_slave_gamma.product(  idINTPRIMARY KEY AUTO_INCREMENT,  nameVARCHAR(50)NOT NULL,  price DOUBLE(10,2)NOT NULL DEFAULT0);INSERT INTOproduct_slave_gamma.product (name, price)VALUES('slaveGamma','1');

配置数据源

spring.datasource.type=com.zaxxer.hikari.HikariDataSource# Master datasource configspring.datasource.hikari.master.name=masterspring.datasource.hikari.master.driver-class-name=com.mysql.jdbc.Driverspring.datasource.hikari.master.jdbc-url=jdbc:mysql://localhost/product_master?useSSL=falsespring.datasource.hikari.master.port=3306spring.datasource.hikari.master.username=rootspring.datasource.hikari.master.password=123456# SlaveAlpha datasource configspring.datasource.hikari.slave-alpha.name=SlaveAlphaspring.datasource.hikari.slave-alpha.driver-class-name=com.mysql.jdbc.Driverspring.datasource.hikari.slave-alpha.jdbc-url=jdbc:mysql://localhost/product_slave_alpha?useSSL=falsespring.datasource.hikari.slave-alpha.port=3306spring.datasource.hikari.slave-alpha.username=rootspring.datasource.hikari.slave-alpha.password=123456# SlaveBeta datasource configspring.datasource.hikari.slave-beta.name=SlaveBetaspring.datasource.hikari.slave-beta.driver-class-name=com.mysql.jdbc.Driverspring.datasource.hikari.slave-beta.jdbc-url=jdbc:mysql://localhost/product_slave_beta?useSSL=falsespring.datasource.hikari.slave-beta.port=3306spring.datasource.hikari.slave-beta.username=rootspring.datasource.hikari.slave-beta.password=123456# SlaveGamma datasource configspring.datasource.hikari.slave-gamma.name=SlaveGammaspring.datasource.hikari.slave-gamma.driver-class-name=com.mysql.jdbc.Driverspring.datasource.hikari.slave-gamma.jdbc-url=jdbc:mysql://localhost/product_slave_gamma?useSSL=falsespring.datasource.hikari.slave-gamma.port=3306spring.datasource.hikari.slave-gamma.username=rootspring.datasource.hikari.slave-gamma.password=123456spring.aop.proxy-target-class=trueserver.port=9999

配置数据源

packagecn.com.hellowood.dynamicdatasource.common;publicenumDataSourceKey {master,slaveAlpha,slaveBeta,slaveGamma}

packagecn.com.hellowood.dynamicdatasource.configuration;importorg.slf4j.Logger;importorg.slf4j.LoggerFactory;importorg.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;publicclassDynamicRoutingDataSourceextendsAbstractRoutingDataSource {privatefinalLoggerlogger =LoggerFactory.getLogger(getClass());@OverrideprotectedObjectdetermineCurrentLookupKey() {logger.info("Current DataSource is [{}]",DynamicDataSourceContextHolder.getDataSourceKey());returnDynamicDataSourceContextHolder.getDataSourceKey();    }}

packagecn.com.hellowood.dynamicdatasource.configuration;importorg.mybatis.spring.SqlSessionFactoryBean;importorg.springframework.boot.jdbc.DataSourceBuilder;importorg.springframework.boot.context.properties.ConfigurationProperties;importorg.springframework.context.annotation.Bean;importorg.springframework.context.annotation.Configuration;importorg.springframework.context.annotation.Primary;importjavax.sql.DataSource;importjava.util.HashMap;importjava.util.Map;@ConfigurationpublicclassDataSourceConfigurer {/**     * master DataSource     * @Primary 注解用于标识默认使用的 DataSource Bean，因为有5个 DataSource Bean，该注解可用于 master     * 或 slave DataSource Bean, 但不能用于 dynamicDataSource Bean, 否则会产生循环调用     *     * @ConfigurationProperties 注解用于从 application.properties 文件中读取配置，为 Bean 设置属性     * @return data source     */@Bean("master")@Primary@ConfigurationProperties(prefix ="spring.datasource.hikari.master")publicDataSourcemaster() {returnDataSourceBuilder.create().build();    }/**     * Slave alpha data source.     *     * @return the data source     */@Bean("slaveAlpha")@ConfigurationProperties(prefix ="spring.datasource.hikari.slave-alpha")publicDataSourceslaveAlpha() {returnDataSourceBuilder.create().build();    }/**     * Slave beta data source.     *     * @return the data source     */@Bean("slaveBeta")@ConfigurationProperties(prefix ="spring.datasource.hikari.slave-beta")publicDataSourceslaveBeta() {returnDataSourceBuilder.create().build();    }/**     * Slave gamma data source.     *     * @return the data source     */@Bean("slaveGamma")@ConfigurationProperties(prefix ="spring.datasource.druid.slave-gamma")publicDataSourceslaveGamma() {returnDataSourceBuilder.create().build();    }/**     * Dynamic data source.     *     * @return the data source     */@Bean("dynamicDataSource")publicDataSourcedynamicDataSource() {DynamicRoutingDataSourcedynamicRoutingDataSource =newDynamicRoutingDataSource();Map<Object,Object>dataSourceMap =newHashMap<>(4);dataSourceMap.put(DataSourceKey.master.name(),master());dataSourceMap.put(DataSourceKey.slaveAlpha.name(),slaveAlpha());dataSourceMap.put(DataSourceKey.slaveBeta.name(),slaveBeta());dataSourceMap.put(DataSourceKey.slaveGamma.name(),slaveGamma());// 将 master 数据源作为默认指定的数据源dynamicRoutingDataSource.setDefaultTargetDataSource(master());// 将 master 和 slave 数据源作为指定的数据源dynamicRoutingDataSource.setTargetDataSources(dataSourceMap);// 将数据源的 key 放到数据源上下文的 key 集合中，用于切换时判断数据源是否有效DynamicDataSourceContextHolder.dataSourceKeys.addAll(dataSourceMap.keySet());// 将 Slave 数据源的 key 放在集合中，用于轮循DynamicDataSourceContextHolder.slaveDataSourceKeys.addAll(dataSourceMap.keySet());DynamicDataSourceContextHolder.slaveDataSourceKeys.remove(DataSourceKey.master.name());returndynamicRoutingDataSource;    }/**     * 配置 SqlSessionFactoryBean     * @ConfigurationProperties 在这里是为了将 MyBatis 的 mapper 位置和持久层接口的别名设置到     * Bean 的属性中，如果没有使用 *.xml 则可以不用该配置，否则将会产生 invalid bond statement 异常     *     * @return the sql session factory bean     */@Bean@ConfigurationProperties(prefix ="mybatis")publicSqlSessionFactoryBeansqlSessionFactoryBean() {SqlSessionFactoryBeansqlSessionFactoryBean =newSqlSessionFactoryBean();// 配置 MyBatissqlSessionFactoryBean.setTypeAliasesPackage("cn.com.hellowood.dynamicdatasource.mapper");sqlSessionFactoryBean.setMapperLocations(newPathMatchingResourcePatternResolver().getResources("mappers/**Mapper.xml"));// 配置数据源，此处配置为关键配置，如果没有将 dynamicDataSource 作为数据源则不能实现切换sqlSessionFactoryBean.setDataSource(dynamicDataSource());returnsqlSessionFactoryBean;    }/**     * 注入 DataSourceTransactionManager 用于事务管理     */@BeanpublicPlatformTransactionManagertransactionManager() {returnnewDataSourceTransactionManager(dynamicDataSource());    }    }

packagecn.com.hellowood.dynamicdatasource.configuration;importcn.com.hellowood.dynamicdatasource.common.DataSourceKey;importorg.slf4j.Logger;importorg.slf4j.LoggerFactory;importjava.util.ArrayList;importjava.util.List;publicclassDynamicDataSourceContextHolder {privatestaticfinalLoggerlogger =LoggerFactory.getLogger(DynamicDataSourceContextHolder.class);/**     * 用于轮循的计数器     */privatestaticintcounter =0;/**     * Maintain variable for every thread, to avoid effect other thread     */privatestaticfinalThreadLocal<Object>CONTEXT_HOLDER =ThreadLocal.withInitial(DataSourceKey.master);/**     * All DataSource List     */publicstaticList<Object>dataSourceKeys =newArrayList<>();/**     * The constant slaveDataSourceKeys.     */publicstaticList<Object>slaveDataSourceKeys =newArrayList<>();/**     * To switch DataSource     *     * @param key the key     */publicstaticvoidsetDataSourceKey(Stringkey) {CONTEXT_HOLDER.set(key);    }/**     * Use master data source.     */publicstaticvoiduseMasterDataSource() {CONTEXT_HOLDER.set(DataSourceKey.master);    }/**     * 当使用只读数据源时通过轮循方式选择要使用的数据源     */publicstaticvoiduseSlaveDataSource() {try {intdatasourceKeyIndex =counter %slaveDataSourceKeys.size();CONTEXT_HOLDER.set(String.valueOf(slaveDataSourceKeys.get(datasourceKeyIndex)));counter++;        }catch (Exceptione) {logger.error("Switch slave datasource failed, error message is {}",e.getMessage());useMasterDataSource();e.printStackTrace();        }     }/**     * Get current DataSource     *     * @return data source key     */publicstaticStringgetDataSourceKey() {returnCONTEXT_HOLDER.get();    }/**     * To set DataSource as default     */publicstaticvoidclearDataSourceKey() {CONTEXT_HOLDER.remove();    }/**     * Check if give DataSource is in current DataSource list     *     * @param key the key     * @return boolean boolean     */publicstaticbooleancontainDataSourceKey(Stringkey) {returndataSourceKeys.contains(key);    }}

packagecn.com.hellowood.dynamicdatasource.configuration;importorg.aspectj.lang.JoinPoint;importorg.aspectj.lang.annotation.After;importorg.aspectj.lang.annotation.Aspect;importorg.aspectj.lang.annotation.Before;importorg.aspectj.lang.annotation.Pointcut;importorg.slf4j.Logger;importorg.slf4j.LoggerFactory;importorg.springframework.stereotype.Component;@Aspect@ComponentpublicclassDynamicDataSourceAspect {privatestaticfinalLoggerlogger =LoggerFactory.getLogger(DynamicDataSourceAspect.class);privatefinalString[]QUERY_PREFIX = {"get"};@Pointcut("execution( * cn.com.hellowood.dynamicdatasource.mapper.*.*(..))")publicvoiddaoAspect() {    }@Before("daoAspect()")publicvoidswitchDataSource(JoinPointpoint) {BooleanisQueryMethod =isQueryMethod(point.getSignature().getName());if (isQueryMethod) {DynamicDataSourceContextHolder.useSlaveDataSource();logger.info("Switch DataSource to [{}] in Method [{}]",DynamicDataSourceContextHolder.getDataSourceKey(),point.getSignature());        }    }@After("daoAspect()")publicvoidrestoreDataSource(JoinPointpoint) {DynamicDataSourceContextHolder.clearDataSourceKey();logger.info("Restore DataSource to [{}] in Method [{}]",DynamicDataSourceContextHolder.getDataSourceKey(),point.getSignature());    }privateBooleanisQueryMethod(StringmethodName) {for (Stringprefix :QUERY_PREFIX) {if (methodName.startsWith(prefix)) {returntrue;            }        }returnfalse;    }}

配置 Product REST API 接口

packagecn.com.hellowood.dynamicdatasource.controller;importcn.com.hellowood.dynamicdatasource.common.CommonResponse;importcn.com.hellowood.dynamicdatasource.common.ResponseUtil;importcn.com.hellowood.dynamicdatasource.model.Product;importcn.com.hellowood.dynamicdatasource.service.ProductService;importcn.com.hellowood.dynamicdatasource.error.ServiceException;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.web.bind.annotation.*;@RestController@RequestMapping("/product")publicclassProductController {@AutowiredprivateProductServiceproductService;@GetMapping("/{id}")publicCommonResponsegetProduct(@PathVariable("id")LongproductId)throwsServiceException {returnResponseUtil.generateResponse(productService.select(productId));    }@GetMappingpublicCommonResponsegetAllProduct() {returnResponseUtil.generateResponse(productService.getAllProduct());    }@PutMapping("/{id}")publicCommonResponseupdateProduct(@PathVariable("id")LongproductId,@RequestBodyProductnewProduct)throwsServiceException {returnResponseUtil.generateResponse(productService.update(productId,newProduct));    }@DeleteMapping("/{id}")publicCommonResponsedeleteProduct(@PathVariable("id")longproductId)throwsServiceException {returnResponseUtil.generateResponse(productService.delete(productId));    }@PostMappingpublicCommonResponseaddProduct(@RequestBodyProductnewProduct)throwsServiceException {returnResponseUtil.generateResponse(productService.add(newProduct));    }}

packagecn.com.hellowood.dynamicdatasource.service;importcn.com.hellowood.dynamicdatasource.mapper.ProductDao;importcn.com.hellowood.dynamicdatasource.model.Product;importcn.com.hellowood.dynamicdatasource.error.ServiceException;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.dao.DataAccessException;importorg.springframework.stereotype.Service;importorg.springframework.transaction.annotation.Transactional;importjava.util.List;@ServicepublicclassProductService {@AutowiredprivateProductDaoproductDao;publicProductselect(longproductId)throwsServiceException {Productproduct =productDao.select(productId);if (product ==null) {thrownewServiceException("Product:" +productId +" not found");        }returnproduct;    }@Transactional(rollbackFor =DataAccessException.class)publicProductupdate(longproductId,ProductnewProduct)throwsServiceException {if (productDao.update(newProduct) <=0) {thrownewServiceException("Update product:" +productId +"failed");        }returnnewProduct;    }@Transactional(rollbackFor =DataAccessException.class)publicbooleanadd(ProductnewProduct)throwsServiceException {Integernum =productDao.insert(newProduct);if (num <=0) {thrownewServiceException("Add product failed");        }returntrue;    }@Transactional(rollbackFor =DataAccessException.class)publicbooleandelete(longproductId)throwsServiceException {Integernum =productDao.delete(productId);if (num <=0) {thrownewServiceException("Delete product:" +productId +"failed");        }returntrue;    }publicList<Product>getAllProduct() {returnproductDao.getAllProduct();    }}

packagecn.com.hellowood.dynamicdatasource.mapper;importcn.com.hellowood.dynamicdatasource.model.Product;importorg.apache.ibatis.annotations.Mapper;importorg.apache.ibatis.annotations.Param;importjava.util.List;@MapperpublicinterfaceProductDao {Productselect(@Param("id")longid);Integerupdate(Productproduct);Integerinsert(Productproduct);Integerdelete(longproductId);List<Product>getAllProduct();}

注意

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