Spring boot实现数据库读写分离的方法
背景
数据库配置主从之后,如何在代码层面实现读写分离?
用户自定义设置数据库路由
Springboot提供了AbstractRoutingDataSource根据用户定义的规则选择当前的数据库,这样我们可以在执行查询之前,设置读取从库,在执行完成后,恢复到主库。
实现可动态路由的数据源,在每次数据库查询操作前执行
ReadWriteSplitRoutingDataSource.java
importorg.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource; /** *@authorsongrgg *@since1.0 */ publicclassReadWriteSplitRoutingDataSourceextendsAbstractRoutingDataSource{ @Override protectedObjectdetermineCurrentLookupKey(){ returnDbContextHolder.getDbType(); } }
线程私有路由配置,用于ReadWriteSplitRoutingDataSource动态读取配置
DbContextHolder.java
/** *@authorsongrgg *@since1.0 */ publicclassDbContextHolder{ publicenumDbType{ MASTER, SLAVE } privatestaticfinalThreadLocal<DbType>contextHolder=newThreadLocal<>(); publicstaticvoidsetDbType(DbTypedbType){ if(dbType==null){ thrownewNullPointerException(); } contextHolder.set(dbType); } publicstaticDbTypegetDbType(){ returncontextHolder.get()==null?DbType.MASTER:contextHolder.get(); } publicstaticvoidclearDbType(){ contextHolder.remove(); } }
AOP优化代码
利用AOP将设置数据库的操作从代码中抽离,这里的粒度控制在方法级别,所以利用注解的形式标注这个方法涉及的数据库事务只读,走从库。
只读注解,用于标注方法的数据库操作只走从库。
ReadOnlyConnection.java
packagecom.wallstreetcn.hatano.config; importjava.lang.annotation.ElementType; importjava.lang.annotation.Retention; importjava.lang.annotation.RetentionPolicy; importjava.lang.annotation.Target; /** *Indicatesthedatabaseoperationsisboundtotheslavedatabase. *AOPinterceptorwillsetthedatabasetotheslavewiththisinterface. *@authorsongrgg *@since1.0 */ @Target({ElementType.METHOD,ElementType.TYPE}) @Retention(RetentionPolicy.RUNTIME) public@interfaceReadOnlyConnection{ }
ReadOnlyConnectionInterceptor.java
importorg.aspectj.lang.ProceedingJoinPoint; importorg.aspectj.lang.annotation.Around; importorg.aspectj.lang.annotation.Aspect; importorg.slf4j.Logger; importorg.slf4j.LoggerFactory; importorg.springframework.core.Ordered; importorg.springframework.stereotype.Component; /** *Interceptthedatabaseoperations,binddatabasetoread-onlydatabaseasthisannotation *isapplied. *@authorsongrgg *@since1.0 */ @Aspect @Component publicclassReadOnlyConnectionInterceptorimplementsOrdered{ privatestaticfinalLoggerlogger=LoggerFactory.getLogger(ReadOnlyConnectionInterceptor.class); @Around("@annotation(readOnlyConnection)") publicObjectproceed(ProceedingJoinPointproceedingJoinPoint,ReadOnlyConnectionreadOnlyConnection)throwsThrowable{ try{ logger.info("setdatabaseconnectiontoreadonly"); DbContextHolder.setDbType(DbContextHolder.DbType.SLAVE); Objectresult=proceedingJoinPoint.proceed(); returnresult; }finally{ DbContextHolder.clearDbType(); logger.info("restoredatabaseconnection"); } } @Override publicintgetOrder(){ return0; } }
UserService.java
@ReadOnlyConnection publicList<User>getUsers(Integerpage,Integerlimit){ returnrepository.findAll(newPageRequest(page,limit)); }
配置Druid数据库连接池
build.gradle
compile("com.alibaba:druid:1.0.18")
groovy依赖注入
配置dataSource为可路由数据源
context.groovy
importcom.alibaba.druid.pool.DruidDataSource importDbContextHolder importReadWriteSplitRoutingDataSource **SOMEINITIALIZEDCODELOADPROPERTIES** defdataSourceMaster=newDruidDataSource() dataSourceMaster.url=properties.get('datasource.master.url') println("mastersetto"+dataSourceMaster.url) dataSourceMaster.username=properties.get('datasource.master.username') dataSourceMaster.password=properties.get('datasource.master.password') defdataSourceSlave=newDruidDataSource() dataSourceSlave.url=properties.get('datasource.slave.url') println("slavesetto"+dataSourceSlave.url) dataSourceSlave.username=properties.get('datasource.slave.username') dataSourceSlave.password=properties.get('datasource.slave.password') beans{ dataSource(ReadWriteSplitRoutingDataSource){bean-> targetDataSources=[ (DbContextHolder.DbType.MASTER):dataSourceMaster, (DbContextHolder.DbType.SLAVE):dataSourceSlave ] } }
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持毛票票。