基于mybatis plus实现数据源动态添加、删除、切换，自定义数据源的示例代码

<!--mybatis-plus-->

<dependency>

     <groupId>com.baomidou</groupId>

     <artifactId>mybatis-plus-boot-starter</artifactId>

     <version> 3.4 . 3.4 </version>

</dependency>

<!--dynamic-datasource-->

<dependency>

     <groupId>com.baomidou</groupId>

     <artifactId>dynamic-datasource-spring-boot-starter</artifactId>

     <version> 3.4 . 1 </version>

</dependency>

@RestController

@RequestMapping ( "/datasources" )

public class DataSourceController {

     @Resource

     private DataSource dataSource;

     @Resource

     private DefaultDataSourceCreator dataSourceCreator;

     @GetMapping ( "list" )

     public Set<String> list() {

         DynamicRoutingDataSource ds = (DynamicRoutingDataSource) dataSource;

         return ds.getDataSources().keySet();

     }

     @PostMapping ( "add" )

     public Set<String> add( @Validated @RequestBody DataSourceDTO dto) {

         DataSourceProperty dataSourceProperty = new DataSourceProperty();

         BeanUtils.copyProperties(dto, dataSourceProperty);

         DynamicRoutingDataSource ds = (DynamicRoutingDataSource) dataSource;

         DataSource dataSource = dataSourceCreator.createDataSource(dataSourceProperty);

         ds.addDataSource(dto.getPollName(), dataSource);

         return ds.getDataSources().keySet();

     }

     @DeleteMapping ( "remove" )

     public void remove(String name) {

         DynamicRoutingDataSource ds = (DynamicRoutingDataSource) dataSource;

         ds.removeDataSource(name);

     }

}

package com.starsray.dynamic.datasource.annotation;

import java.lang.annotation.*;

/**

  * <p>

  * 用户标识仅可以使用默认数据源

  * </p>

  *

  * @author starsray

  * @since 2021-11-10

  */

@Target ({ElementType.METHOD})

@Retention (RetentionPolicy.RUNTIME)

@Documented

public @interface DefaultDs {

}

package com.starsray.dynamic.datasource.interceptor;

import com.baomidou.dynamic.datasource.toolkit.DynamicDataSourceContextHolder;

import com.starsray.dynamic.datasource.annotation.DefaultDs;

import com.starsray.dynamic.datasource.exception.ExceptionEnum;

import com.starsray.dynamic.datasource.exception.GlobalException;

import lombok.RequiredArgsConstructor;

import org.apache测试数据mons.lang3.StringUtils;

import org.aspectj.lang.JoinPoint;

import org.aspectj.lang.Signature;

import org.aspectj.lang.annotation.AfterReturning;

import org.aspectj.lang.annotation.Aspect;

import org.aspectj.lang.annotation.Before;

import org.aspectj.lang.annotation.Pointcut;

import org.aspectj.lang.reflect.MethodSignature;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Component;

import org.springframework.web.context.request.RequestAttributes;

import org.springframework.web.context.request.RequestContextHolder;

import org.springframework.web.context.request.ServletRequestAttributes;

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;

import java.lang.reflect.Method;

/**

  * <p>

  * 数据源选择器切面

  * </p>

  *

  * @author starsray

  * @since 2021-11-10

  */

@Aspect

@Component

@RequiredArgsConstructor (onConstructor_ = @Autowired )

public class DsInterceptor implements HandlerInterceptor {

     @Pointcut ( "execution(public * com.starsray.dynamic.datasource.controller.*.*(..))" )

     public void datasourcePointcut() {

     }

     /**

      * 前置操作，拦截具体请求，获取header里的数据源id，设置线程变量里，用于后续切换数据源

      */

     @Before ( "datasourcePointcut()" )

     public void doBefore(JoinPoint joinPoint) {

         Signature signature = joinPoint.getSignature();

         MethodSignature methodSignature = (MethodSignature) signature;

         Method method = methodSignature.getMethod();

         // 排除不可切换数据源的方法

         DefaultDs annotation = method.getAnnotation(DefaultDs. class );

         if ( null != annotation) {

             DynamicDataSourceContextHolder.push( "master" );

         } else {

             RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();

             ServletRequestAttributes attributes = (ServletRequestAttributes) requestAttributes;

             assert attributes != null ;

             HttpServletRequest request = attributes.getRequest();

             String header = request.getHeader( "tenantName" );

             if (StringUtils.isNotBlank(header)) {

                 DynamicDataSourceContextHolder.push(header);

             } else {

                 throw new GlobalException(ExceptionEnum.NOT_TENANT);

             }

         }

     }

     /**

      * 后置操作，设置回默认的数据源id

      */

     @AfterReturning ( "datasourcePointcut()" )

     public void doAfter() {

         DynamicDataSourceContextHolder.push( "master" );

     }

}

@DS ( "#header.tenantId" )

public class HeaderProcessor extends DsProcessor {

     private static final String HEADER = "#header" ;

     @Override

     public boolean matches(String key) {

         return key.startsWith(HEADER);

     }

     @Override

     public String doDetermineDatasource(MethodInvocation invocation, String key) {

         HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();

         return request.getHeader(key.substring( 8 ));

     }

}

@Configuration

public class CustomerDynamicDataSourceConfig{

    @Bean

    public DsProcessor dsProcessor() {

         DsHeaderProcessor headerProcessor = new DsHeaderProcessor();

         DsSessionProcessor sessionProcessor = new DsSessionProcessor();

         DsSpelExpressionProcessor spelExpressionProcessor = new DsSpelExpressionProcessor();

         headerProcessor.setNextProcessor(sessionProcessor);

         sessionProcessor.setNextProcessor(spelExpressionProcessor);

         return headerProcessor;

    }

}

DynamicDataSourceContextHolder.push( "master" );

public interface DynamicDataSourceProvider {

     Map<String, DataSource> loadDataSources();

}

public abstract class AbstractDataSourceProvider implements DynamicDataSourceProvider {

     private static final Logger log = LoggerFactory.getLogger(AbstractDataSourceProvider. class );

     @Autowired

     private DefaultDataSourceCreator defaultDataSourceCreator;

     public AbstractDataSourceProvider() {

     }

     protected Map<String, DataSource> createDataSourceMap(Map<String, DataSourceProperty> dataSourcePropertiesMap) {

         Map<String, DataSource> dataSourceMap = new HashMap(dataSourcePropertiesMap.size() * 2 );

         Iterator var3 = dataSourcePropertiesMap.entrySet().iterator();

         while (var3.hasNext()) {

             Entry<String, DataSourceProperty> item = (Entry)var3.next();

             String dsName = (String)item.getKey();

             DataSourceProperty dataSourceProperty = (DataSourceProperty)item.getValue();

             String poolName = dataSourceProperty.getPoolName();

             if (poolName == null || "" .equals(poolName)) {

                 poolName = dsName;

             }

             dataSourceProperty.setPoolName(poolName);

             dataSourceMap.put(dsName, this .defaultDataSourceCreator.createDataSource(dataSourceProperty));

         }

         return dataSourceMap;

     }

}

package com.digital.cnzz.dynamic.ds.provider;

import com.baomidou.dynamic.datasource.provider.AbstractJdbcDataSourceProvider;

import com.baomidou.dynamic.datasource.provider.DynamicDataSourceProvider;

import com.baomidou.dynamic.datasource.spring.boot.autoconfigure.DataSourceProperty;

import com.digital.cnzz.dynamic.ds.config.DefaultDsConfig;

import com.digital.cnzz.dynamic.ds.constant.DsDriverEnum;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.Primary;

import javax.annotation.Resource;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.HashMap;

import java.util.Map;

@Primary

@Configuration

public class DsProvider {

     @Resource

     private DefaultDsConfig defaultDsConfig;

     @Bean

     public DynamicDataSourceProvider jdbcDynamicDataSourceProvider() {

         return new AbstractJdbcDataSourceProvider(defaultDsConfig.getDriverClassName(), defaultDsConfig.getUrl(), defaultDsConfig.getUsername(), defaultDsConfig.getPassword()) {

             @Override

             protected Map<String, DataSourceProperty> executeStmt(Statement statement) {

                 Map<String, DataSourceProperty> dataSourcePropertiesMap = null ;

                 ResultSet rs = null ;

                 try {

                     dataSourcePropertiesMap = new HashMap<>();

                     rs = statement.executeQuery( "SELECT * FROM DYNAMIC_DATASOURCE_INSTANCE" );

                     while (rs.next()) {

                         String name = rs.getString( "name" );

                         DataSourceProperty property = new DataSourceProperty();

                         property.setDriverClassName(rs.getString( "driver" ));

                         property.setUrl(rs.getString( "url" ));

                         property.setUsername(rs.getString( "username" ));

                         property.setPassword(rs.getString( "password" ));

                         dataSourcePropertiesMap.put(name, property);

                     }

                 } catch (SQLException e) {

                     e.printStackTrace();

                 } finally {

                     try {

                         if (rs != null ) {

                             rs.close();

                         }

                     } catch (SQLException e) {

                         e.printStackTrace();

                     }

                     try {

                         statement.close();

                     } catch (SQLException e) {

                         e.printStackTrace();

                     }

                 }

                 return dataSourcePropertiesMap;

             }

         };

     }

}