注:本文的多数据源配置及切换的实现方法是,在框架中封装,具体项目中配置及使用,也适用于多模块项目
配置文件数据源读取
通过springboot的Envioment和Binder对象进行读取,无需手动声明DataSource的Bean
yml数据源配置格式如下:
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spring: datasource: master: type: com.alibaba.druid.pool.DruidDataSource driverClassName: com.mysql.cj.jdbc.Driver url: jdbc:mysql: //localhost:3306/main? useUnicode= true &characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&serverTimezone=Asia/Shanghai username: root password: 11111 cluster: - key: db1 type: com.alibaba.druid.pool.DruidDataSource driverClassName: com.mysql.cj.jdbc.Driver url: jdbc:mysql: //localhost:3306/haopanframetest_db1? useUnicode= true &characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&serverTimezone=Asia/Shanghai username: root password: 11111 - key: db2 type: com.alibaba.druid.pool.DruidDataSource driverClassName: com.mysql.cj.jdbc.Driver url: jdbc:mysql: //localhost:3306/haopanframetest_db2? useUnicode= true &characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&serverTimezone=Asia/Shanghai username: root password: 11111 |
master为主数据库必须配置,cluster下的为从库,选择性配置
获取配置文件信息代码如下
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@Autowired private Environment env; @Autowired private ApplicationContext applicationContext; private Binder binder; binder = Binder.get(env); List<Map> configs = binder.bind( "spring.datasource.cluster" , Bindable.listOf(Map. class )).get(); for ( int i = 0 ; i < configs.size(); i++) { config = configs.get(i); String key = ConvertOp.convert2String(config.get( "key" )); String type = ConvertOp.convert2String(config.get( "type" )); String driverClassName = ConvertOp.convert2String(config.get( "driverClassName" )); String url = ConvertOp.convert2String(config.get( "url" )); String username = ConvertOp.convert2String(config.get( "username" )); String password = ConvertOp.convert2String(config.get( "password" )); } |
动态加入数据源
定义获取数据源的Service,具体项目中进行实现
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public interface ExtraDataSourceService { List<DataSourceModel> getExtraDataSourc(); } |
获取对应Service的所有实现类进行调用
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private List<DataSourceModel> getExtraDataSource(){ List<DataSourceModel> dataSourceModelList = new ArrayList<>(); Map<String, ExtraDataSourceService> res = applicationContext.getBeansOfType(ExtraDataSourceService. class ); for (Map.Entry en :res.entrySet()) { ExtraDataSourceService service = (ExtraDataSourceService)en.getValue(); dataSourceModelList.addAll(service.getExtraDataSourc()); } return dataSourceModelList; } |
通过代码进行数据源注册
主要是用过继承类AbstractRoutingDataSource,重写setTargetDataSources/setDefaultTargetDataSource方法
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// 创建数据源 public boolean createDataSource(String key, String driveClass, String url, String username, String password, String databasetype) { try { try { // 排除连接不上的错误 Class.forName(driveClass); DriverManager.getConnection(url, username, password); // 相当于连接数据库 } catch (Exception e) { return false ; } @SuppressWarnings ( "resource" ) DruidDataSource druidDataSource = new DruidDataSource(); druidDataSource.setName(key); druidDataSource.setDriverClassName(driveClass); druidDataSource.setUrl(url); druidDataSource.setUsername(username); druidDataSource.setPassword(password); druidDataSource.setInitialSize( 1 ); //初始化时建立物理连接的个数。初始化发生在显示调用init方法,或者第一次getConnection时 druidDataSource.setMaxActive( 20 ); //最大连接池数量 druidDataSource.setMaxWait( 60000 ); //获取连接时最大等待时间,单位毫秒。当链接数已经达到了最大链接数的时候,应用如果还要获取链接就会出现等待的现象,等待链接释放并回到链接池,如果等待的时间过长就应该踢掉这个等待,不然应用很可能出现雪崩现象 druidDataSource.setMinIdle( 5 ); //最小连接池数量 String validationQuery = "select 1 from dual" ; druidDataSource.setTestOnBorrow( true ); //申请连接时执行validationQuery检测连接是否有效,这里建议配置为TRUE,防止取到的连接不可用 druidDataSource.setTestWhileIdle( true ); //建议配置为true,不影响性能,并且保证安全性。申请连接的时候检测,如果空闲时间大于timeBetweenEvictionRunsMillis,执行validationQuery检测连接是否有效。 druidDataSource.setValidationQuery(validationQuery); //用来检测连接是否有效的sql,要求是一个查询语句。如果validationQuery为null,testOnBorrow、testOnReturn、testWhileIdle都不会起作用。 druidDataSource.setFilters( "stat" ); //属性类型是字符串,通过别名的方式配置扩展插件,常用的插件有:监控统计用的filter:stat日志用的filter:log4j防御sql注入的filter:wall druidDataSource.setTimeBetweenEvictionRunsMillis( 60000 ); //配置间隔多久才进行一次检测,检测需要关闭的空闲连接,单位是毫秒 druidDataSource.setMinEvictableIdleTimeMillis( 180000 ); //配置一个连接在池中最小生存的时间,单位是毫秒,这里配置为3分钟180000 druidDataSource.setKeepAlive( true ); //打开druid.keepAlive之后,当连接池空闲时,池中的minIdle数量以内的连接,空闲时间超过minEvictableIdleTimeMillis,则会执行keepAlive操作,即执行druid.validationQuery指定的查询SQL,一般为select * from dual,只要minEvictableIdleTimeMillis设置的小于防火墙切断连接时间,就可以保证当连接空闲时自动做保活检测,不会被防火墙切断 druidDataSource.setRemoveAbandoned( true ); //是否移除泄露的连接/超过时间限制是否回收。 druidDataSource.setRemoveAbandonedTimeout( 3600 ); //泄露连接的定义时间(要超过最大事务的处理时间);单位为秒。这里配置为1小时 druidDataSource.setLogAbandoned( true ); //移除泄露连接发生是是否记录日志 druidDataSource.init(); this .dynamicTargetDataSources.put(key, druidDataSource); setTargetDataSources( this .dynamicTargetDataSources); // 将map赋值给父类的TargetDataSources super .afterPropertiesSet(); // 将TargetDataSources中的连接信息放入resolvedDataSources管理 log.info(key+ "数据源初始化成功" ); //log.info(key+"数据源的概况:"+druidDataSource.dump()); return true ; } catch (Exception e) { log.error(e + "" ); return false ; } } |
通过切面注解统一切换
定义注解
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@Retention (RetentionPolicy.RUNTIME) @Target ({ElementType.METHOD, ElementType.TYPE, ElementType.PARAMETER}) @Documented public @interface TargetDataSource { String value() default "master" ; //该值即key值 } |
定义基于线程的切换类
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public class DBContextHolder { private static Logger log = LoggerFactory.getLogger(DBContextHolder. class ); // 对当前线程的操作-线程安全的 private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>(); // 调用此方法,切换数据源 public static void setDataSource(String dataSource) { contextHolder.set(dataSource); log.info( "已切换到数据源:{}" ,dataSource); } // 获取数据源 public static String getDataSource() { return contextHolder.get(); } // 删除数据源 public static void clearDataSource() { contextHolder.remove(); log.info( "已切换到主数据源" ); } } |
定义切面
方法的注解优先级高于类注解,一般用于Service的实现类
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@Aspect @Component @Order (Ordered.HIGHEST_PRECEDENCE) public class DruidDBAspect { private static Logger logger = LoggerFactory.getLogger(DruidDBAspect. class ); @Autowired private DynamicDataSource dynamicDataSource; /** * 切面点 指定注解 * */ @Pointcut ( "@annotation(com.haopan.frame.common.annotation.TargetDataSource) " + "|| @within(com.haopan.frame.common.annotation.TargetDataSource)" ) public void dataSourcePointCut() { } /** * 拦截方法指定为 dataSourcePointCut * */ @Around ( "dataSourcePointCut()" ) public Object around(ProceedingJoinPoint point) throws Throwable { MethodSignature signature = (MethodSignature) point.getSignature(); Class targetClass = point.getTarget().getClass(); Method method = signature.getMethod(); TargetDataSource targetDataSource = (TargetDataSource)targetClass.getAnnotation(TargetDataSource. class ); TargetDataSource methodDataSource = method.getAnnotation(TargetDataSource. class ); if (targetDataSource != null || methodDataSource != null ){ String value; if (methodDataSource != null ){ value = methodDataSource.value(); } else { value = targetDataSource.value(); } DBContextHolder.setDataSource(value); logger.info( "DB切换成功,切换至{}" ,value); } try { return point.proceed(); } finally { logger.info( "清除DB切换" ); DBContextHolder.clearDataSource(); } } } |
分库切换
开发过程中某个库的某个表做了拆分操作,相同的某一次数据库操作可能对应到不同的库,需要对方法级别进行精确拦截,可以定义一个业务层面的切面,规定每个方法必须第一个参数为dbName,根据具体业务找到对应的库传参
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@Around ( "dataSourcePointCut()" ) public Object around(ProceedingJoinPoint point) throws Throwable { MethodSignature signature = (MethodSignature) point.getSignature(); Class targetClass = point.getTarget().getClass(); Method method = signature.getMethod(); ProjectDataSource targetDataSource = (ProjectDataSource)targetClass.getAnnotation(ProjectDataSource. class ); ProjectDataSource methodDataSource = method.getAnnotation(ProjectDataSource. class ); String value = "" ; if (targetDataSource != null || methodDataSource != null ){ //获取方法定义参数 DefaultParameterNameDiscoverer discover = new DefaultParameterNameDiscoverer(); String[] parameterNames = discover.getParameterNames(method); //获取传入目标方法的参数 Object[] args = point.getArgs(); for ( int i= 0 ;i<parameterNames.length;i++){ String pName = parameterNames[i]; if (pName.toLowerCase().equals( "dbname" )){ value = ConvertOp.convert2String(args[i]); } } if (!StringUtil.isEmpty(value)){ DBContextHolder.setDataSource(value); logger.info( "DB切换成功,切换至{}" ,value); } } try { return point.proceed(); } finally { if (!StringUtil.isEmpty(value)){ logger.info( "清除DB切换" ); DBContextHolder.clearDataSource(); } } } |
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原文链接:https://www.cnblogs.com/yanpeng19940119/archive/2020/09/20/13702454.html