MyBatis - 使用示例（五）SpringBoot配置数据库密码加密

我就是我 2023-01-02 02:25 183阅读 0赞

# MyBatis - 使用示例（五）SpringBoot配置数据库密码加密 #

> 你在使用 MyBatis 的过程中，是否有想过多个数据源应该如何配置，如何去实现？出于这个好奇心，我在 [Druid Wiki][] 的**数据库多数据源**中知晓 Spring 提供了对多数据源的支持，基于 Spring 提供的 AbstractRoutingDataSource，可以自己实现数据源的切换。

### 一、配置动态数据源 ###

下面就如何配置动态数据源提供一个简单的实现：

`org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource`，代码如下：

public abstract class AbstractRoutingDataSource extends AbstractDataSource implements InitializingBean { 
    
    	@Nullable
    	private Object defaultTargetDataSource;
    
    	@Nullable
    	private Map<Object, DataSource> resolvedDataSources;
    
    	@Nullable
    	private DataSource resolvedDefaultDataSource;
    
    	@Override
    	public Connection getConnection() throws SQLException { 
    		return determineTargetDataSource().getConnection();
    	}
    
    	@Override
    	public Connection getConnection(String username, String password) throws SQLException { 
    		return determineTargetDataSource().getConnection(username, password);
    	}
    
    	protected DataSource determineTargetDataSource() { 
    		Assert.notNull(this.resolvedDataSources, "DataSource router not initialized");
            // 确定当前要使用的数据源
    		Object lookupKey = determineCurrentLookupKey();
    		DataSource dataSource = this.resolvedDataSources.get(lookupKey);
    		if (dataSource == null && (this.lenientFallback || lookupKey == null)) { 
    			dataSource = this.resolvedDefaultDataSource;
    		}
    		if (dataSource == null) { 
    			throw new IllegalStateException("Cannot determine target DataSource for lookup key [" + lookupKey + "]");
    		}
    		return dataSource;
    	}
    
    	/** * Determine the current lookup key. This will typically be implemented to check a thread-bound transaction context. * <p> * Allows for arbitrary keys. The returned key needs to match the stored lookup key type, as resolved by the * {@link #resolveSpecifiedLookupKey} method. */
    	@Nullable
    	protected abstract Object determineCurrentLookupKey();
    	
    	// 省略相关代码...
    }

重写 AbstractRoutingDataSource 的 determineCurrentLookupKey() 方法，可以实现对多数据源的支持

思路：

1.  重写其 determineCurrentLookupKey() 方法，支持选择不同的数据源
2.  初始化多个 DataSource 数据源到 AbstractRoutingDataSource 的 resolvedDataSources 属性中
3.  然后通过 Spring AOP， 以自定义注解作为切点，根据不同的数据源的 Key 值，设置当前线程使用的数据源

接下来的实现方式是 Spring Boot 结合 Druid 配置动态数据源

### （一）引入依赖 ###

基于 **3.继承SpringBoot** 中已添加的依赖再添加对AOP支持的依赖，如下：

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-aop</artifactId>
    </dependency>

### （二）开始实现 ###

#### 1. DataSourceContextHolder ####

DataSourceContextHolder 使用 ThreadLocal 存储当前线程指定的数据源的 Key 值，代码如下：

package cn.tzh.mybatis.config;
    
    import lombok.extern.slf4j.Slf4j;
    
    import java.util.HashSet;
    import java.util.Set;
    
    /** * @author tzh * @date 2021/1/4 11:42 */
    @Slf4j
    public class DataSourceContextHolder { 
    
        /** * 线程本地变量 */
        private static final ThreadLocal<String> DATASOURCE_KEY = new ThreadLocal<>();
    
        /** * 配置的所有数据源的 Key 值 */
        public static Set<Object> ALL_DATASOURCE_KEY = new HashSet<>();
    
        /** * 设置当前线程的数据源的 Key * * @param dataSourceKey 数据源的 Key 值 */
        public static void setDataSourceKey(String dataSourceKey) { 
            if (ALL_DATASOURCE_KEY.contains(dataSourceKey)) { 
                DATASOURCE_KEY.set(dataSourceKey);
            } else { 
                log.warn("the datasource [{}] does not exist", dataSourceKey);
            }
        }
    
        /** * 获取当前线程的数据源的 Key 值 * * @return 数据源的 Key 值 */
        public static String getDataSourceKey() { 
            return DATASOURCE_KEY.get();
        }
    
        /** * 移除当前线程持有的数据源的 Key 值 */
        public static void clear() { 
            DATASOURCE_KEY.remove();
        }
    }

#### 2. MultipleDataSource ####

重写其 AbstractRoutingDataSource 的 determineCurrentLookupKey() 方法，代码如下：

package cn.tzh.mybatis.config;
    
    import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
    
    /** * @author tzh * @date 2021/1/4 11:44 */
    public class MultipleDataSource extends AbstractRoutingDataSource { 
    
        /** * 返回当前线程是有的数据源的 Key * * @return dataSourceKey */
        @Override
        protected Object determineCurrentLookupKey() { 
            return DataSourceContextHolder.getDataSourceKey();
        }
    }

#### 3. DataSourceAspect切面 ####

使用 Spring AOP 功能，定义一个切面，用于设置当前需要使用的数据源，代码如下：

package cn.tzh.mybatis.config;
    
    import lombok.extern.log4j.Log4j2;
    import org.aspectj.lang.JoinPoint;
    import org.aspectj.lang.annotation.After;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.aspectj.lang.reflect.MethodSignature;
    import org.springframework.stereotype.Component;
    
    import java.lang.reflect.Method;
    
    /** * @author tzh * @date 2021/1/4 11:46 */
    @Aspect
    @Component
    @Log4j2
    public class DataSourceAspect { 
    
        @Before("@annotation(cn.tzh.mybatis.config.TargetDataSource)")
        public void before(JoinPoint joinPoint) { 
            MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();
            Method method = methodSignature.getMethod();
            if (method.isAnnotationPresent(TargetDataSource.class)) { 
                TargetDataSource targetDataSource = method.getAnnotation(TargetDataSource.class);
                DataSourceContextHolder.setDataSourceKey(targetDataSource.value());
                log.info("set the datasource of the current thread to [{}]", targetDataSource.value());
            } else if (joinPoint.getTarget().getClass().isAnnotationPresent(TargetDataSource.class)) { 
                TargetDataSource targetDataSource = joinPoint.getTarget().getClass().getAnnotation(TargetDataSource.class);
                DataSourceContextHolder.setDataSourceKey(targetDataSource.value());
                log.info("set the datasource of the current thread to [{}]", targetDataSource.value());
            }
        }
    
        @After("@annotation(cn.tzh.mybatis.config.TargetDataSource)")
        public void after() { 
            DataSourceContextHolder.clear();
            log.info("clear the datasource of the current thread");
        }
    }

#### 4. DruidConfig ####

Druid 配置类，代码如下：

package cn.tzh.mybatis.config;
    
    import com.alibaba.druid.support.spring.stat.DruidStatInterceptor;
    import org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    /** * @author tzh * @date 2021/1/4 11:49 */
    @Configuration
    public class DruidConfig { 
        
    
        @Bean(value = "druid-stat-interceptor")
        public DruidStatInterceptor druidStatInterceptor() { 
            return new DruidStatInterceptor();
        }
    
        @Bean
        public BeanNameAutoProxyCreator beanNameAutoProxyCreator() { 
            BeanNameAutoProxyCreator beanNameAutoProxyCreator = new BeanNameAutoProxyCreator();
            beanNameAutoProxyCreator.setProxyTargetClass(true);
            // 设置要监控的bean的id
            beanNameAutoProxyCreator.setInterceptorNames("druid-stat-interceptor");
            return beanNameAutoProxyCreator;
        }
    }

#### 5. MultipleDataSourceConfig ####

MyBatis 的配置类，配置了 2 个数据源，代码如下：

package cn.tzh.mybatis.config;
    
    import com.alibaba.druid.pool.DruidDataSource;
    import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
    import org.apache.ibatis.mapping.DatabaseIdProvider;
    import org.apache.ibatis.plugin.Interceptor;
    import org.apache.ibatis.scripting.LanguageDriver;
    import org.apache.ibatis.session.ExecutorType;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.type.TypeHandler;
    import org.mybatis.spring.SqlSessionFactoryBean;
    import org.mybatis.spring.SqlSessionTemplate;
    import org.mybatis.spring.boot.autoconfigure.ConfigurationCustomizer;
    import org.mybatis.spring.boot.autoconfigure.MybatisProperties;
    import org.mybatis.spring.boot.autoconfigure.SpringBootVFS;
    import org.springframework.beans.BeanWrapperImpl;
    import org.springframework.beans.factory.ObjectProvider;
    import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.boot.context.properties.EnableConfigurationProperties;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.core.io.ResourceLoader;
    import org.springframework.jdbc.datasource.DataSourceTransactionManager;
    import org.springframework.transaction.PlatformTransactionManager;
    import org.springframework.util.CollectionUtils;
    import org.springframework.util.ObjectUtils;
    import org.springframework.util.StringUtils;
    
    import javax.sql.DataSource;
    import java.beans.FeatureDescriptor;
    import java.util.*;
    import java.util.stream.Collectors;
    import java.util.stream.Stream;
    
    /** * @author tzh * @projectName code-demo * @title MultipleDataSourceConfig * @description * @date 2021/1/4 13:43 */
    @Configuration
    @EnableConfigurationProperties({ MybatisProperties.class})
    public class MultipleDataSourceConfig { 
    
    
        private final MybatisProperties properties;
        private final Interceptor[] interceptors;
        private final TypeHandler[] typeHandlers;
        private final LanguageDriver[] languageDrivers;
        private final ResourceLoader resourceLoader;
        private final DatabaseIdProvider databaseIdProvider;
        private final List<ConfigurationCustomizer> configurationCustomizers;
    
        public MultipleDataSourceConfig(MybatisProperties properties, ObjectProvider<Interceptor[]> interceptorsProvider, ObjectProvider<TypeHandler[]> typeHandlersProvider, ObjectProvider<LanguageDriver[]> languageDriversProvider, ResourceLoader resourceLoader, ObjectProvider<DatabaseIdProvider> databaseIdProvider, ObjectProvider<List<ConfigurationCustomizer>> configurationCustomizersProvider) { 
            this.properties = properties;
            this.interceptors = (Interceptor[]) interceptorsProvider.getIfAvailable();
            this.typeHandlers = (TypeHandler[]) typeHandlersProvider.getIfAvailable();
            this.languageDrivers = (LanguageDriver[]) languageDriversProvider.getIfAvailable();
            this.resourceLoader = resourceLoader;
            this.databaseIdProvider = (DatabaseIdProvider) databaseIdProvider.getIfAvailable();
            this.configurationCustomizers = (List) configurationCustomizersProvider.getIfAvailable();
        }
    
    
        @Bean(name = "master", initMethod = "init", destroyMethod = "close")
        @ConfigurationProperties(prefix = "spring.datasource.druid.master")
        public DruidDataSource master() { 
            return DruidDataSourceBuilder.create().build();
        }
    
        @Bean(name = "slave", initMethod = "init", destroyMethod = "close")
        @ConfigurationProperties(prefix = "spring.datasource.druid.slave")
        public DruidDataSource slave() { 
            return DruidDataSourceBuilder.create().build();
        }
    
        @Bean(name = "dynamicDataSource")
        public DataSource dynamicDataSource() { 
            MultipleDataSource dynamicRoutingDataSource = new MultipleDataSource();
    
            Map<Object, Object> dataSources = new HashMap<>();
            dataSources.put("master", master());
            dataSources.put("slave", slave());
    
            dynamicRoutingDataSource.setDefaultTargetDataSource(master());
            dynamicRoutingDataSource.setTargetDataSources(dataSources);
    
            DataSourceContextHolder.ALL_DATASOURCE_KEY.addAll(dataSources.keySet());
    
            return dynamicRoutingDataSource;
        }
    
        @Bean
        public SqlSessionFactory sqlSessionFactory() throws Exception { 
            SqlSessionFactoryBean factory = new SqlSessionFactoryBean();
            factory.setDataSource(dynamicDataSource());
            factory.setVfs(SpringBootVFS.class);
            if (StringUtils.hasText(this.properties.getConfigLocation())) { 
                factory.setConfigLocation(this.resourceLoader.getResource(this.properties.getConfigLocation()));
            }
    
            this.applyConfiguration(factory);
            if (this.properties.getConfigurationProperties() != null) { 
                factory.setConfigurationProperties(this.properties.getConfigurationProperties());
            }
    
            if (!ObjectUtils.isEmpty(this.interceptors)) { 
                factory.setPlugins(this.interceptors);
            }
    
            if (this.databaseIdProvider != null) { 
                factory.setDatabaseIdProvider(this.databaseIdProvider);
            }
    
            if (StringUtils.hasLength(this.properties.getTypeAliasesPackage())) { 
                factory.setTypeAliasesPackage(this.properties.getTypeAliasesPackage());
            }
    
            if (this.properties.getTypeAliasesSuperType() != null) { 
                factory.setTypeAliasesSuperType(this.properties.getTypeAliasesSuperType());
            }
    
            if (StringUtils.hasLength(this.properties.getTypeHandlersPackage())) { 
                factory.setTypeHandlersPackage(this.properties.getTypeHandlersPackage());
            }
    
            if (!ObjectUtils.isEmpty(this.typeHandlers)) { 
                factory.setTypeHandlers(this.typeHandlers);
            }
    
            if (!ObjectUtils.isEmpty(this.properties.resolveMapperLocations())) { 
                factory.setMapperLocations(this.properties.resolveMapperLocations());
            }
    
            Set<String> factoryPropertyNames = (Set) Stream.of((new BeanWrapperImpl(SqlSessionFactoryBean.class)).getPropertyDescriptors()).map(FeatureDescriptor::getName).collect(Collectors.toSet());
            Class<? extends LanguageDriver> defaultLanguageDriver = this.properties.getDefaultScriptingLanguageDriver();
            if (factoryPropertyNames.contains("scriptingLanguageDrivers") && !ObjectUtils.isEmpty(this.languageDrivers)) { 
                factory.setScriptingLanguageDrivers(this.languageDrivers);
                if (defaultLanguageDriver == null && this.languageDrivers.length == 1) { 
                    defaultLanguageDriver = this.languageDrivers[0].getClass();
                }
            }
    
            if (factoryPropertyNames.contains("defaultScriptingLanguageDriver")) { 
                factory.setDefaultScriptingLanguageDriver(defaultLanguageDriver);
            }
    
            return factory.getObject();
        }
    
        private void applyConfiguration(SqlSessionFactoryBean factory) { 
            org.apache.ibatis.session.Configuration configuration = this.properties.getConfiguration();
            if (configuration == null && !StringUtils.hasText(this.properties.getConfigLocation())) { 
                configuration = new org.apache.ibatis.session.Configuration();
            }
    
            if (configuration != null && !CollectionUtils.isEmpty(this.configurationCustomizers)) { 
                Iterator var3 = this.configurationCustomizers.iterator();
    
                while (var3.hasNext()) { 
                    ConfigurationCustomizer customizer = (ConfigurationCustomizer) var3.next();
                    customizer.customize(configuration);
                }
            }
    
            factory.setConfiguration(configuration);
        }
    
        @Bean
        public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) { 
            ExecutorType executorType = this.properties.getExecutorType();
            return executorType != null ? new SqlSessionTemplate(sqlSessionFactory, executorType) : new SqlSessionTemplate(sqlSessionFactory);
        }
    
        @Bean
        public PlatformTransactionManager masterTransactionManager() { 
            // 配置事务管理器
            return new DataSourceTransactionManager(dynamicDataSource());
        }
    }

#### 6. 添加配置 ####

server:
      port: 9092
      servlet:
        context-path: /mybatis-springboot-demo
      tomcat:
        accept-count: 200
        min-spare-threads: 200
    spring:
      application:
        name: mybatis-springboot-demo
      profiles:
        active: test
      servlet:
        multipart:
          max-file-size: 100MB
          max-request-size: 100MB
      datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        druid:
          master:
            driver-class-name: com.mysql.cj.jdbc.Driver
            url: jdbc:mysql://127.0.0.1:3306/mybatis-demo
            username: root
            password: root
            initial-size: 5 # 初始化时建立物理连接的个数
            min-idle: 20 # 最小连接池数量
            max-active: 20 # 最大连接池数量
          slave:
            driver-class-name: com.mysql.cj.jdbc.Driver
            url: jdbc:mysql://127.0.0.1:3306/mybatis-demo1
            username: root
            password: root
            initial-size: 5 # 初始化时建立物理连接的个数
            min-idle: 20 # 最小连接池数量
            max-active: 20 # 最大连接池数量
    mybatis:
      type-aliases-package: cn.tzh.mybatis.entity
      mapper-locations: classpath:cn/tzh/mybatis/mapper/*.xml
      config-location: classpath:mybatis-config.xml
    pagehelper:
      helper-dialect: mysql
      reasonable: true # 分页合理化参数
      offset-as-page-num: true # 将 RowBounds 中的 offset 参数当成 pageNum 使用
      supportMethodsArguments: true # 支持通过 Mapper 接口参数来传递分页参数

其中分别定义了 `master` 和 `slave` 数据源的相关配置

这样一来，在 `DataSourceAspect` 切面中根据自定义注解，设置 `DataSourceContextHolder` 当前线程所使用的数据源的 Key 值，`MultipleDataSource` 动态数据源则会根据该值设置需要使用的数据源，完成了动态数据源的切换

#### 7. 使用示例 ####

在 Mapper 接口上面添加自定义注解 `@TargetDataSource`，如下：

package cn.tzh.mybatis.mapper;
    
    import cn.tzh.mybatis.config.TargetDataSource;
    import cn.tzh.mybatis.entity.User;
    import org.apache.ibatis.annotations.Mapper;
    import org.apache.ibatis.annotations.Param;
    
    /** * @author tzh * @date 2020/12/28 14:29 */
    @Mapper
    public interface UserMapper { 
    
        User selectUserOne(@Param("id") Long id);
    
        @TargetDataSource("slave")
        User selectUserTwo(@Param("id") Long id);
    }

### 总结 ###

上面就如何配置动态数据源的实现方式**仅提供一种思路**，其中关于多事务方面并没有实现，采用 Spring 提供的事务管理器，如果同一个方法中使用了多个数据源，并不支持多事务的，需要自己去实现（笔者能力有限），可以整合JAT组件，参考：[SpringBoot2 整合JTA组件多数据源事务管理][SpringBoot2 _JTA]

分布式事务解决方案**推荐使用** [Seata 分布式服务框架][Seata]

动态多数据源**推荐使用**： [**一个基于SpringBoot的动态多数据源组件**][SpringBoot]

\--------------最后感谢大家的阅读，愿大家技术越来越流弊！--------------

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1phY2tfdHpo_size_16_color_FFFFFF_t_70]

\--------------也希望大家给我点支持，谢谢各位大佬了！！！--------------

[Druid Wiki]: https://github.com/alibaba/druid/wiki/%E6%95%B0%E6%8D%AE%E5%BA%93%E5%A4%9A%E6%95%B0%E6%8D%AE%E6%BA%90
[SpringBoot2 _JTA]: https://www.cnblogs.com/cicada-smile/p/13289306.html
[Seata]: https://github.com/seata/seata/
[SpringBoot]: https://baomidou.gitee.io/dynamic-datasource-doc/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1phY2tfdHpo_size_16_color_FFFFFF_t_70]: /images/20221120/6e60acb1937942c4b2317146d659a9a5.png