背景

最近让我做一个大数据的系统，分析了一下，麻烦的地方就是多数据源切换抽取数据。考虑到可以跨服务器跨数据库抽数，再整理数据，就配置了这个动态数据源的解决方案。在此分享给大家。

实现方案

数据库配置文件

我们项目使用的是yml形式的配置文件，采用的是hikari的数据库连接池。第一步我们自然是配置多个数据库源头。
我们找到spring的datasource，在下方配置三个数据源。

spring:application:name: dynamicDatasourcedatasource:test1:driver-class-name: com.mysql.jdbc.Driverurl: jdbc:mysql://127.0.0.1:3306/test1?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=falseusername: rootpassword: 123456test2:driver-class-name: com.mysql.jdbc.Driverurl: jdbc:mysql://127.0.0.1:3306/test2?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=falseusername: rootpassword: 123456test3:driver-class-name: com.mysql.jdbc.Driverurl: jdbc:mysql://127.0.0.1:3306/test3?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=falseusername: rootpassword: 123456hikari:leak-detection-threshold: 2000

定义数据源实体类

我们可以建立个datasourceBean文件夹专门管理数据源的实体类。
我们这里要建立三个实体类。分别对应test1，test2，test3

@Configuration
public class Test1DataSourceBean {@Value("${spring.datasource.test1.driver-class-name}")private String test1Driver;@Value("${spring.datasource.test1.url}")private String test1Url;@Value("${spring.datasource.test1.username}")private String test1Username;@Value("${spring.datasource.test1.password}")private String test1Password;@Bean(name="test1DataSource")public DataSource test1DataSource() throws Exception{HikariDataSource dataSource = new HikariDataSource();dataSource.setDriverClassName(test1Driver);dataSource.setJdbcUrl(test1Url);dataSource.setUsername(test1Username);dataSource.setPassword(test1Password);return dataSource;}
}

@Configuration
public class Test2DataSourceBean {@Value("${spring.datasource.test2.driver-class-name}")private String test2Driver;@Value("${spring.datasource.test2.url}")private String test2Url;@Value("${spring.datasource.test2.username}")private String test2Username;@Value("${spring.datasource.test2.password}")private String test2Password;@Bean(name="test2DataSource")public DataSource test2DataSource() throws Exception{HikariDataSource dataSource = new HikariDataSource();dataSource.setDriverClassName(test2Driver);dataSource.setJdbcUrl(test2Url);dataSource.setUsername(test2Username);dataSource.setPassword(test2Password);return dataSource;}
}

@Configuration
public class Test3DataSourceBean {@Value("${spring.datasource.test3.driver-class-name}")private String test3Driver;@Value("${spring.datasource.test3.url}")private String test3Url;@Value("${spring.datasource.test3.username}")private String test3Username;@Value("${spring.datasource.test3.password}")private String test3Password;@Bean(name="test3DataSource")public DataSource test3DataSource() throws Exception{HikariDataSource dataSource = new HikariDataSource();dataSource.setDriverClassName(test3Driver);dataSource.setJdbcUrl(test3Url);dataSource.setUsername(test3Username);dataSource.setPassword(test3Password);return dataSource;}
}

定义一个枚举类管理数据源

public enum DatabaseType {test1("test1", "test1"),test2("test2", "test2"),test3("test3","test3");private String name;private String value;DatabaseType(String name, String value){this.name = name;this.value = value;}public String getName(){return name;}public String getValue(){return value;}
}

定义一个线程安全的数据源容器

public class DatabaseContextHolder {private static final ThreadLocal<DatabaseType> contextHolder = new ThreadLocal<>();public static void setDatabaseType(DatabaseType type){contextHolder.set(type);}public static DatabaseType getDatabaseType(){return contextHolder.get();}
}

定义动态数据源

public class DynamicDataSource extends AbstractRoutingDataSource{protected Object determineCurrentLookupKey() {return DatabaseContextHolder.getDatabaseType();}
}

mybatis配置类

网上的很多文章配置出来都会产生数据源循环依赖的问题，这里解决了这个问题。

@Configuration
@MapperScan(basePackages="cn.test.jichi", sqlSessionFactoryRef="sessionFactory")
public class MybatisConfig {/***  @Description:设置动态数据源*/@Bean(name="dynamicDataSource")@Primarypublic DynamicDataSource DataSource(@Qualifier("test1DataSource") DataSource test1DataSource,@Qualifier("test2DataSource") DataSource test2DataSource,@Qualifier("test3DataSource") DataSource test3DataSource){Map<Object, Object> targetDataSource = new HashMap<>();targetDataSource.put(DatabaseType.test1, test1DataSource);targetDataSource.put(DatabaseType.test2, test2DataSource);targetDataSource.put(DatabaseType.test3, test3DataSource);DynamicDataSource dataSource = new DynamicDataSource();dataSource.setTargetDataSources(targetDataSource);dataSource.setDefaultTargetDataSource(test1DataSource);return dataSource;}/***  @Description:根据动态数据源创建sessionFactory*/@Bean(name="sessionFactory")public SqlSessionFactory sessionFactory(@Qualifier("test1DataSource") DataSource test1DataSource,@Qualifier("test2DataSource") DataSource test2DataSource,@Qualifier("test3DataSource") DataSource test3DataSource) throws Exception{SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();//构造方法，解决动态数据源循环依赖问题。sessionFactoryBean.setDataSource(this.DataSource(test1DataSource,test2DataSource, test3DataSource));return sessionFactoryBean.getObject();}
}

package cn.chinaunicom.sdsi.utils;import cn.chinaunicom.sdsi.config.dynamicDataSourceConfig.DatabaseContextHolder;
import cn.chinaunicom.sdsi.config.dynamicDataSourceConfig.DatabaseType;/***  @Description:封装数据源选择*/
public class DynamicDataSourceUtils {public static void chooseBasicDataSource(){DatabaseContextHolder.setDatabaseType(DatabaseType.basic);}public static void chooseBranchDataSource(){DatabaseContextHolder.setDatabaseType(DatabaseType.branch);}}

提供一个示例

public void testDymnaicDatasource(){//不切换数据源默认是自己的。System.out.println("-----默认数据源");DemoEntity totalCount = demoMapper.getTotalCount();String nameCount1 = totalCount.getNameCount();String ageCount2 = totalCount.getAgeCount();System.out.println("nameCount:"+nameCount1);System.out.println("ageCount:"+ageCount2);//数据源切换为branchSystem.out.println("-----数据源为test2");DynamicDataSourceUtils.chooseBranchDataSource();Integer nameCount = demoMapper.getNameCount();Integer ageCount = demoMapper.getAgeCount();System.out.println("nameCount:"+nameCount);System.out.println("ageCount:"+ageCount);//数据源为basicSystem.out.println("-----数据源为test3");DynamicDataSourceUtils.chooseBasicDataSource();Integer ageCount1 = demoMapper.getAgeCount();System.out.println("ageCount:"+ageCount1);}

总结

至此实现了多数据源的动态切换。可以在同一个方法里面进行操作多个数据源。