So implementieren Sie SpringBoot-Umschaltung mehrerer Datenquellen

spring:
  datasource:
    default-db-key: voidme
    multi-db:
      - voidme:
          driver-class-name: com.mysql.cj.jdbc.Driver
          username: root
          password: root
          url: jdbc:mysql://192.168.42.153:3306/voidme?characterEncoding=utf8&autoReconnect=true&failOverReadOnly=false&maxReconnects=10&useSSL=false
      - xcdef:
          driver-class-name: com.mysql.cj.jdbc.Driver
          username: root
          password: root
          url: jdbc:mysql://192.168.42.153:3306/xcdef?characterEncoding=utf8&autoReconnect=true&failOverReadOnly=false&maxReconnects=10&useSSL=false


mybatis:
  #1.classpath：只会到你的classes路径中查找找文件。
  #2.classpath*：不仅会到classes路径，还包括jar文件中(classes路径)进行查找。
  mapper-locations: classpath*:/mapper/**/*Mapper.xml    # mapper映射文件位置
  type-aliases-package: com.**.entity    # 实体类所在的位置
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl   #用于控制台打印sql语句
    map-underscore-to-camel-case: true #开启将带有下划线的表字段 映射为驼峰格式的实体类属性

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());
    }
}