SpringBootの複数データソース切り替えの実装方法

package com.dynamicdatadource.dynamic;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

public class DynamicDataSource extends AbstractRoutingDataSource {

    @Value("${spring.datasource.default-db-key}")
    private String defaultDbKey;

    @Override
    protected Object determineCurrentLookupKey() {
        String currentDb = DynamicDataSourceService.currentDb();
        if (currentDb == null) {
            return defaultDbKey;
        }
        return currentDb;
    }
}

package com.dynamicdatadource.dynamic;

import com.application.ApplicationContextProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.jdbc.DataSourceBuilder;

import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

public class DynamicDataSourceService  {
    private static final Logger log = LoggerFactory.getLogger(DynamicDataSourceService.class);

    private static final Map<Object, Object> dataSources = new HashMap<>();
    private static final ThreadLocal<String> dbKeys = ThreadLocal.withInitial(() -> null);

    /**
     * 动态添加一个数据源
     *
     * @param name       数据源的key
     * @param dataSource 数据源对象
     */
    public static void addDataSource(String name, DataSource dataSource) {
        DynamicDataSource dynamicDataSource = ApplicationContextProvider.getApplicationContext().getBean(DynamicDataSource.class);
        dataSources.put(name, dataSource);
        dynamicDataSource.setTargetDataSources(dataSources);
        dynamicDataSource.afterPropertiesSet();
        log.info("添加了数据源:{}",name);
    }

    /**
     * @param name   数据源的key
     * @param driverClassName  驱动
     * @param url     数据库连接地址
     * @param username   数据库账户
     * @param password   数据库密码
     */
    public static void addDataSource(String name, String driverClassName,String url,String username,String password) {
        DataSourceBuilder<?> builder = DataSourceBuilder.create();
        builder.driverClassName(driverClassName);
        builder.username(username);
        builder.password(password);
        builder.url(url);
        addDataSource(name,builder.build());
        log.info("添加了数据源:{}",name);
    }
    /**
     * 切换数据源
     */
    public static void switchDb(String dbKey) {
        dbKeys.set(dbKey);
    }

    /**
     * 重置数据源(切换为默认的数据源)
     */
    public static void resetDb() {
        dbKeys.remove();
    }

    /**
     * 获取当前数据源的key
     */
    public static String currentDb() {
        return dbKeys.get();
    }
}

package com.dynamicdatadource.dynamic;

import lombok.Data;
import org.apache.ibatis.logging.Log;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.boot.context.properties.ConfigurationProperties;
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 java.io.IOException;
import java.util.HashMap;
import java.util.Map;

@Configuration
@ConfigurationProperties(prefix = "mybatis")
@Data
public class DynamicDataSourceConfig {

    private String mapperLocations;
    private String typeAliasesPackage;
    @Data
    public class MybatisConfiguration{
        private String logImpl;
        private boolean mapUnderscoreToCamelCase;
    }
    private  MybatisConfiguration configuration=new MybatisConfiguration();


    /**
     * 动态数据源
     */
    @Bean
    public DynamicDataSource dynamicDataSource() {
        DynamicDataSource dataSource = new DynamicDataSource();
        Map<Object, Object> targetDataSources = new HashMap<>();
        dataSource.setTargetDataSources(targetDataSources);
        return dataSource;
    }

    /**
     * 会话工厂Mybaitis
     */
    @Bean
    public SqlSessionFactoryBean sqlSessionFactoryBean() throws IOException, ClassNotFoundException {
        org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
        configuration.setMapUnderscoreToCamelCase(this.configuration.isMapUnderscoreToCamelCase()); //开启驼峰命名
        configuration.setLogImpl((Class<? extends Log>) Class.forName(this.configuration.getLogImpl())); //控制台打印sql日志
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dynamicDataSource());
        sqlSessionFactoryBean.setConfiguration(configuration);
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources(mapperLocations));
        sqlSessionFactoryBean.setTypeAliasesPackage(typeAliasesPackage);
        return sqlSessionFactoryBean;
    }

    /**
     * 事务管理器
     */
    @Bean
    public PlatformTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dynamicDataSource());
    }
}

package com.dao.config;

import com.dao.DatasourceDao;
import com.dynamicdatadource.aop.DynamicDataSourceAnno;
import com.dynamicdatadource.dynamic.DynamicDataSourceService;
import com.entity.DataSourceEneity;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.sql.DataSource;
import java.util.List;

//从数据库中查询出全部的数据源,添加到数据源容器中

/**
 * 表结构如下:
 *
 * CREATE TABLE `t_datasource` (
 *   `id` int(11) NOT NULL,
 *   `key` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '绑定的key,用于数据源的切换',
 *   `url` text CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '数据库连接地址',
 *   `username` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '数据库用户名',
 *   `password` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '数据库密码',
 *   `driverClassName` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '数据库驱动',
 *   `type` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '数据库类型:  mysql ,oracle,..',
 *   `state` int(2) NOT NULL COMMENT '是否可用: 1可用 ,2不可用',
 *   PRIMARY KEY (`id`),
 *   UNIQUE KEY `key` (`key`)
 * ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
 *
 * 上表要放入到默认数据源中的数据库里才行
 */
@Component
public class MysqlDataSourceInitialize implements ApplicationRunner  {

    @Autowired
    private DatasourceDao datasourceDao;

    //项目启动后执行初始化数据源
    @Override
    public void run(ApplicationArguments args) throws Exception {
        try {
            List<DataSourceEneity> dataSources = datasourceDao.getDataSources();
            for (DataSourceEneity dataSource : dataSources) {
                DynamicDataSourceService.addDataSource(dataSource.getKey(),dataSource.getDataSource());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

@Data
public class DataSourceEneity {
    private int id;
    private String key;
    private String url;
    private String username;
    private String password;
    private String driverClassName;
    private String type;
    private int state;

    public  DataSource getDataSource() {
        DataSourceBuilder<?> builder = DataSourceBuilder.create();
        builder.driverClassName(driverClassName);
        builder.username(username);
        builder.password(password);
        builder.url(url);
        return  builder.build();
    }
}