Spring 配置多数据源并实现Druid自动切换

本是古典何须时尚 2023-02-28 15:24 11阅读 0赞

一、多数据源切换  
    实现数据库的读写分离，这种情况往往是读多写少的情况，例如电商平台。既然数据库读写分离了，那么代码层也就需要读写不同的数据库了。实现方法应该有不少，我知道有插件实现，判断写请求还是读请求来请求不同的数据库，还有代码实现，不同的SQL访问不同的数据源，也就是接下来要说的多数据源。  
  1、 类或者方法上只需要添加注解，即可实现多数据源切换，具体逻辑实现已经封装在数据访问层，业务逻辑处理层等多个组件进行使用  
   2、类或者方法上添加如下注解：@DataSource(ContextConstant.DataSourceType.CTS) 或者@DataSource(ContextConstant.DataSourceType.REPORT) ，分别表示切换到XXX数据库和XXS数据库  
    3、若需要再增加其他数据源，只需要在配置文件applicationContext.xml中增加数据配置信息，在常量接口ContextConstant中增量对应数据源类型即可。代码侵入性小，方便切换  
 二、代码配置信息  
   1、applicationContext.xml配置

<bean id = "reportDataSource" class = "com.alibaba.druid.pool.DruidDataSource" destroy-method = "close" >
            
            <property name = "url" value = "${report.jdbc.url}" />
            <property name = "username" value = "${report.jdbc.username}" />
            <property name = "password" value = "${report.jdbc.password}" />
            <property name = "driverClassName" value = "${report.jdbc.driverClassName}" />
            <property name = "filters" value = "config,wall" />
            
            <property name = "maxActive" value = "${report.jdbc.maxActive}" />
            
            <property name = "initialSize" value = "${report.jdbc.initialSize}" />
            
            <property name = "maxWait" value = "${report.jdbc.maxWait}" />
            
            <property name = "minIdle" value = "${report.jdbc.minIdle}" />
            
            <property name = "timeBetweenEvictionRunsMillis" value ="3600000" />
            
            <property name = "minEvictableIdleTimeMillis" value ="3600000" />
            <property name = "validationQuery" value = "select 1 from dual" />
            <property name = "testWhileIdle" value = "true" />
            <property name = "testOnBorrow" value = "false" />
            <property name = "testOnReturn" value = "false" />
           
        </bean>
    
        
        <bean id = "ctsDataSource" class = "com.alibaba.druid.pool.DruidDataSource" destroy-method = "close" >
            
            <property name = "url" value = "${cts.jdbc.url}" />
            <property name = "username" value = "${cts.jdbc.username}" />
            <property name = "password" value = "${cts.jdbc.password}" />
            <property name = "driverClassName" value = "${cts.jdbc.driverClassName}" />
            <property name = "filters" value = "config,wall" />
            
            <property name = "maxActive" value = "${cts.jdbc.maxActive}" />
            
            <property name = "initialSize" value = "${cts.jdbc.initialSize}" />
            
            <property name = "maxWait" value = "${cts.jdbc.maxWait}" />
            
            <property name = "minIdle" value = "${cts.jdbc.minIdle}" />
            
            <property name = "timeBetweenEvictionRunsMillis" value ="3600000" />
            
            <property name = "minEvictableIdleTimeMillis" value ="3600000" />
            <property name = "validationQuery" value = "select 1 from dual" />
            <property name = "testWhileIdle" value = "true" />
            <property name = "testOnBorrow" value = "false" />
            <property name = "testOnReturn" value = "false" />
            <property name="connectionProperties" value="config.decrypt=true;config.decrypt.key=${cts.jdbc.publicKey}" />
        </bean>
    
    
        
        <bean id="multipleDataSource" class="com.fqfin.credit.dbconfig.MultipleDataSource">
            
            <property name="defaultTargetDataSource" ref="reportDataSource" />
            <property name="targetDataSources">
                <map key-type="java.lang.String">
                    <entry key="REPORT" value-ref="reportDataSource"/>
                    <entry key="CTS" value-ref="ctsDataSource"/>
                </map>
            </property>
        </bean>
    
    
        
        <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
            <property name="dataSource" ref="multipleDataSource" />
          
        </bean>
    
    
        
        <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
           
            
            <property name="dataSource" ref="multipleDataSource"/>
            <property name="configLocation" value="classpath:spring/mybatis-config.xml"/>
            <property name="typeAliasesPackage" value="com.fqfin.**.dto" />
            
            <property name="mapperLocations" value="classpath:mapper/**/*Mapper.xml"/>
        </bean>

2、数据源实例

public interface ContextConstant { 
          /** *@Description: 数据源枚举 *@Param: * @Param: null */
        enum DataSourceType { 
            REPORT, CTS
        }
    }

@Target({ ElementType.TYPE,ElementType.METHOD})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface DataSource { 
        /** *@Description: 默认为上报数据库数据源 */
        ContextConstant.DataSourceType value() default ContextConstant.DataSourceType.REPORT;
    }

2、切点表达式，biz数据访问层，business包下可以自动识别（须符合此种路径，方可生效，也可以自定义修改）

/** * @ClassName: DynamicDataSourceAspect * @Description: 切换数据源类 */
    @Component
    @Aspect
    @Order(1)   /**设置为1,优先加载，优先级高于AbstractRoutingDataSource的determineCurrentLookupKey() */
    public class DynamicDataSourceAspect  { 
    
        private static final Logger log = LoggerFactory.getLogger(DynamicDataSourceAspect.class);
    
        /** *@Description: 前置切面 *@Param: * @Param: null */
        @Before("execution(* com.fqfin.credit.business..*.*(..))")
        public void before(JoinPoint point) { 
            try { 
                DataSource annotationOfClass = point.getTarget().getClass().getAnnotation(DataSource.class);
                String methodName = point.getSignature().getName();
                Class[] parameterTypes = ((MethodSignature) point.getSignature()).getParameterTypes();
                Method method = point.getTarget().getClass().getMethod(methodName, parameterTypes);
                DataSource methodAnnotation = method.getAnnotation(DataSource.class);
                methodAnnotation = methodAnnotation == null ? annotationOfClass : methodAnnotation;
                ContextConstant.DataSourceType dataSourceType = methodAnnotation != null
                        && methodAnnotation.value() != null ? methodAnnotation.value() : ContextConstant.DataSourceType.REPORT;
    
                MultipleDataSourceHandler.setRouteKey(dataSourceType.name());
            } catch (NoSuchMethodException e) { 
                log.error("aspect error,err={}",e);
            }
        }
    
        /** *@Description: 后置切面 */
        @After("execution(* com.fqfin.credit.business..*.*(..))")
        public void after(JoinPoint point) { 
            MultipleDataSourceHandler.removeRouteKey();
        }
    }

/** * @ClassName: MultipleDataSource * @Description: 数据源路由实现类 */
    public class MultipleDataSource   extends AbstractRoutingDataSource { 
        private static final Logger log = LoggerFactory.getLogger(DynamicDataSourceAspect.class);
        @Override
        protected Object determineCurrentLookupKey() { 
            String dataSourceCofig = MultipleDataSourceHandler.getRouteKey();
            if (dataSourceCofig == null) { 
                log.info("当前数据源为[report]");
            } else { 
                log.info("当前数据源为{}", dataSourceCofig);
            }
            return dataSourceCofig;
        }
    }

3、使用ThreadLocal存储当前使用数据源实例的key

/** * @ClassName: MultipleDataSourceHandler * @Description: 多数据源持有类,数据源路由 */
    public class MultipleDataSourceHandler { 
        private static final Logger logger = LoggerFactory.getLogger(MultipleDataSourceHandler.class);
        /** * 线程副本，保证线程安全 */
        private static ThreadLocal<String> routeKey = new ThreadLocal<String>();
    
         /** *@Description: 绑定当前线程数据源路由的key 使用完成后必须调用removeRouteKey()方法删除 */
        public static void setRouteKey(String key){ 
            logger.warn("系统切换到{}数据源",key);
            routeKey.set(key);
        }
    
        /** *@Description: 获取当前线程的路由 */
        public static String getRouteKey(){ 
            return routeKey.get();
        }
    
    
    
        /** *@Description: 删除与当前线程绑定的路由key */
        public static void removeRouteKey(){ 
            routeKey.remove();
        }
    
    }

4、类或者方法上添加注解，实现路由

@DataSource(ContextConstant.DataSourceType.CTS)
    @Service
    public class BaiHangAccountService  extends AbstractService { 
        @Autowired
        private BaihangLoanAccountInfoMapper baihangLoanAccountInfoMapper;
    
        public List<BaihangLoanAccountInfo> getList(BaihangLoanAccountInfoExample example, PageRequest pageRequest){ 
          
            return pageList;
    
        }
        @DataSource(ContextConstant.DataSourceType.REPORT)
        public void updateByPrimaryKeySelective( BaihangLoanAccountInfo baihangLoanAccountInfo){ 
            baihangLoanAccountInfoMapper.updateByPrimaryKeySelective(baihangLoanAccountInfo);
        }
    
    }