我是Spring的Spring Webflux / Reactive编程的新手，我对调度程序任务有一些疑问：
调度程序（执行程序线程）在发生错误后不会终止，例如尝试使用Schedulers.parallel（）线程将实体保存到脱机的数据库时。
我的代码实际上看起来像这样：
public Mono<Void> addCatalogEvent(Mono<CatalogEvent> catalogWriteEvent) {
return catalogWriteEvent
.filter(event -> event.getStoreId() != null && event.getCatalogEventType() != null && event.getProductId() != null && event.getUnitPrice() != null)
.switchIfEmpty(Mono.error(new BadRequestException("Not all required fields have been provided for the event!")))
.publishOn(Schedulers.parallel())
.map(event -> {
catalogEventRepository.save(event);
return event;
}).log()
.then()
.onErrorResume(e -> {
Schedulers.shutdownNow();
return Mono.error(new PersistenceException("Persistence failed: " + e.getMessage()));
});
}
但是，当数据库脱机时，我会在控制台上打印出错误消息，但是调度器/执行器不会停止尝试将实体持久化到数据库。该过程一直在进行，并且错误消息一次又一次地输出到控制台...
如果发生错误，如何告诉调度程序/执行器停止运行，以便这些线程不会在发生错误时永远运行？
又如何在数据库再次联机后自动重新启动这些调度程序/执行器线程？
我只是在执行持久性操作的.map（）运算符之后添加了.log（）运算符。在抛出Mono.error（）之后，似乎没有再次执行.log（）操作：
2018-09-21 12:17:12.942 INFO 28234 --- [ctor-http-nio-8] reactor.Mono.Map.2 : onSubscribe(FluxMap.MapSubscriber)
2018-09-21 12:17:12.942 INFO 28234 --- [ctor-http-nio-8] reactor.Mono.Map.2 : request(unbounded)
2018-09-21 12:17:12.965 WARN 28234 --- [ parallel-3] org.postgresql.jdbc.PgConnection : Validating connection.
org.postgresql.util.PSQLException: An I/O error occurred while sending to the backend.
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:333) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:441) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:365) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.jdbc.PgPreparedStatement.executeWithFlags(PgPreparedStatement.java:155) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.jdbc.PgPreparedStatement.executeUpdate(PgPreparedStatement.java:132) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.jdbc.PgConnection.isValid(PgConnection.java:1364) ~[postgresql-42.2.2.jar:42.2.2]
at com.zaxxer.hikari.pool.PoolBase.isConnectionAlive(PoolBase.java:150) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:172) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:148) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:128) [HikariCP-2.7.9.jar:na]
at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.internal.NonContextualJdbcConnectionAccess.obtainConnection(NonContextualJdbcConnectionAccess.java:35) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:106) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getPhysicalConnection(LogicalConnectionManagedImpl.java:136) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getConnectionForTransactionManagement(LogicalConnectionManagedImpl.java:254) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:262) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:214) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:56) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:164) [spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:400) [spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:378) [spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:474) [spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:289) [spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) [spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) [spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:135) [spring-data-jpa-2.0.8.RELEASE.jar:2.0.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) [spring-data-commons-2.0.8.RELEASE.jar:2.0.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at com.sun.proxy.$Proxy92.save(Unknown Source) [na:na]
at com.catalog.api.reactive.service.CatalogEventService.lambda$addCatalogEvent$1(CatalogEventService.java:33) [classes/:na]
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:100) ~[reactor-core-3.1.8.RELEASE.jar:3.1.8.RELEASE]
at reactor.core.publisher.MonoPublishOn$PublishOnSubscriber.run(MonoPublishOn.java:178) ~[reactor-core-3.1.8.RELEASE.jar:3.1.8.RELEASE]
at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:50) ~[reactor-core-3.1.8.RELEASE.jar:3.1.8.RELEASE]
at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:27) ~[reactor-core-3.1.8.RELEASE.jar:3.1.8.RELEASE]
at java.base/java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:264) ~[na:na]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java) ~[na:na]
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[na:na]
at java.base/java.lang.Thread.run(Thread.java:844) ~[na:na]
Caused by: java.io.EOFException: null
at org.postgresql.core.PGStream.receiveChar(PGStream.java:295) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1947) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:306) ~[postgresql-42.2.2.jar:42.2.2]
... 45 common frames omitted
2018-09-21 12:17:12.966 WARN 28234 --- [ parallel-3] com.zaxxer.hikari.pool.PoolBase : HikariPool-1 - Failed to validate connection org.postgresql.jdbc.PgConnection@74772caf (This connection has been closed.)
2018-09-21 12:17:12.969 WARN 28234 --- [ parallel-3] org.postgresql.jdbc.PgConnection : Validating connection.
2018-09-21 12:17:12.970 WARN 28234 --- [ parallel-3] com.zaxxer.hikari.pool.PoolBase : HikariPool-1 - Failed to validate connection org.postgresql.jdbc.PgConnection@5b22b00 (This connection has been closed.)
2018-09-21 12:17:12.972 WARN 28234 --- [ parallel-3] org.postgresql.jdbc.PgConnection : Validating connection.
org.postgresql.util.PSQLException: An I/O error occurred while sending to the backend.
at [...]
Caused by: java.io.EOFException: null
at [...]
2018-09-21 12:17:12.973 WARN 28234 --- [ parallel-3] com.zaxxer.hikari.pool.PoolBase : HikariPool-1 - Failed to validate connection org.postgresql.jdbc.PgConnection@48ed6d4d (This connection has been closed.)
2018-09-21 12:17:12.975 WARN 28234 --- [onnection adder] unknown.jul.logger : ConnectException occurred while connecting to localhost:5432
java.net.ConnectException: Connection refused (Connection refused)
at [...]
2018-09-21 12:17:12.975 WARN 28234 --- [ parallel-3] org.postgresql.jdbc.PgConnection : Validating connection.
org.postgresql.util.PSQLException: An I/O error occurred while sending to the backend.
at [...]
Caused by: java.io.EOFException: null
at [...]
2018-09-21 12:17:12.976 WARN 28234 --- [ parallel-3] com.zaxxer.hikari.pool.PoolBase : HikariPool-1 - Failed to validate connection org.postgresql.jdbc.PgConnection@4f66a7fc (This connection has been closed.)
2018-09-21 12:17:12.977 ERROR 28234 --- [onnection adder] org.postgresql.Driver : Connection error:
org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
at [...]
Caused by: java.net.ConnectException: Connection refused (Connection refused)
at [...]
2018-09-21 12:17:12.978 WARN 28234 --- [ parallel-3] org.postgresql.jdbc.PgConnection : Validating connection.
[SAME ERROR is repeating again until Mono.error() is thrown which results in the following]
2018-09-21 12:17:42.955 WARN 28234 --- [ parallel-3] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 0, SQLState: 08001
2018-09-21 12:17:42.956 ERROR 28234 --- [ parallel-3] o.h.engine.jdbc.spi.SqlExceptionHelper : HikariPool-1 - Connection is not available, request timed out after 30005ms.
2018-09-21 12:17:42.956 WARN 28234 --- [ parallel-3] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 0, SQLState: 08001
2018-09-21 12:17:42.956 ERROR 28234 --- [ parallel-3] o.h.engine.jdbc.spi.SqlExceptionHelper : Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
2018-09-21 12:17:42.969 ERROR 28234 --- [ parallel-3] reactor.Mono.Map.2 : onError(org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection)
2018-09-21 12:17:42.970 ERROR 28234 --- [ parallel-3] reactor.Mono.Map.2 :
org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:450) ~[spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:378) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:474) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:289) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:135) ~[spring-data-jpa-2.0.8.RELEASE.jar:2.0.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.0.8.RELEASE.jar:2.0.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at com.sun.proxy.$Proxy92.save(Unknown Source) ~[na:na]
at com.catalog.api.reactive.service.CatalogEventService.lambda$addCatalogEvent$1(CatalogEventService.java:33) ~[classes/:na]
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:100) ~[reactor-core-3.1.8.RELEASE.jar:3.1.8.RELEASE]
at reactor.core.publisher.MonoPublishOn$PublishOnSubscriber.run(MonoPublishOn.java:178) ~[reactor-core-3.1.8.RELEASE.jar:3.1.8.RELEASE]
at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:50) ~[reactor-core-3.1.8.RELEASE.jar:3.1.8.RELEASE]
at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:27) ~[reactor-core-3.1.8.RELEASE.jar:3.1.8.RELEASE]
at java.base/java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:264) ~[na:na]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java) ~[na:na]
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[na:na]
at java.base/java.lang.Thread.run(Thread.java:844) ~[na:na]
Caused by: org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:48) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:109) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getPhysicalConnection(LogicalConnectionManagedImpl.java:136) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getConnectionForTransactionManagement(LogicalConnectionManagedImpl.java:254) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:262) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:214) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:56) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:164) ~[spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:400) ~[spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
... 26 common frames omitted
Caused by: java.sql.SQLTransientConnectionException: HikariPool-1 - Connection is not available, request timed out after 30005ms.
at com.zaxxer.hikari.pool.HikariPool.createTimeoutException(HikariPool.java:669) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:183) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:148) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:128) ~[HikariCP-2.7.9.jar:na]
at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.internal.NonContextualJdbcConnectionAccess.obtainConnection(NonContextualJdbcConnectionAccess.java:35) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:106) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
... 33 common frames omitted
Caused by: org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:245) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:195) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.Driver.makeConnection(Driver.java:452) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.Driver.connect(Driver.java:254) ~[postgresql-42.2.2.jar:42.2.2]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:117) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:123) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:365) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:194) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:460) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.access$100(HikariPool.java:71) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:699) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:685) ~[HikariCP-2.7.9.jar:na]
at java.base/java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:264) ~[na:na]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java) ~[na:na]
... 3 common frames omitted
Caused by: java.net.ConnectException: Connection refused (Connection refused)
at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:400) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:243) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:225) ~[na:na]
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:402) ~[na:na]
at java.base/java.net.Socket.connect(Socket.java:591) ~[na:na]
at org.postgresql.core.PGStream.<init>(PGStream.java:69) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:156) ~[postgresql-42.2.2.jar:42.2.2]
... 17 common frames omitted
2018-09-21 12:17:51.326 WARN 28234 --- [onnection adder] unknown.jul.logger : ConnectException occurred while connecting to localhost:5432
java.net.ConnectException: Connection refused (Connection refused)
at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:400) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:243) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:225) ~[na:na]
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:402) ~[na:na]
at java.base/java.net.Socket.connect(Socket.java:591) ~[na:na]
at org.postgresql.core.PGStream.<init>(PGStream.java:69) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:156) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49) [postgresql-42.2.2.jar:42.2.2]
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:195) [postgresql-42.2.2.jar:42.2.2]
at org.postgresql.Driver.makeConnection(Driver.java:452) [postgresql-42.2.2.jar:42.2.2]
at org.postgresql.Driver.connect(Driver.java:254) [postgresql-42.2.2.jar:42.2.2]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:117) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:123) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:365) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:194) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:460) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.access$100(HikariPool.java:71) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:699) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:685) [HikariCP-2.7.9.jar:na]
at java.base/java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:264) [na:na]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java) [na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135) [na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [na:na]
at java.base/java.lang.Thread.run(Thread.java:844) [na:na]
2018-09-21 12:17:51.326 ERROR 28234 --- [onnection adder] org.postgresql.Driver : Connection error:
org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:245) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:195) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.Driver.makeConnection(Driver.java:452) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.Driver.connect(Driver.java:254) ~[postgresql-42.2.2.jar:42.2.2]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:117) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:123) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:365) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:194) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:460) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.access$100(HikariPool.java:71) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:699) [HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:685) [HikariCP-2.7.9.jar:na]
at java.base/java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:264) [na:na]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java) [na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135) [na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [na:na]
at java.base/java.lang.Thread.run(Thread.java:844) [na:na]
Caused by: java.net.ConnectException: Connection refused (Connection refused)
at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:400) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:243) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:225) ~[na:na]
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:402) ~[na:na]
at java.base/java.net.Socket.connect(Socket.java:591) ~[na:na]
at org.postgresql.core.PGStream.<init>(PGStream.java:69) ~[postgresql-42.2.2.jar:42.2.2]
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:156) ~[postgresql-42.2.2.jar:42.2.2]
[REPEATED FOREVER]
更新
如果我的数据库出现故障，Hikari线程似乎不会停止建立连接。但是，当我再次重新启动数据库时，错误日志记录似乎停止并且持久性操作未执行。
我可以在数据库脱机时停止重新建立连接过程以停止浪费资源吗？
答案 0 :(得分：0)
对于项目反应器，doOn***操作符是“副作用”操作符，您不应在这些操作符中实现业务逻辑或I / O操作。
在这种情况下，我认为您的存储库调用引发的异常不会转换为反应式链中的错误信号。这可以解释为什么这不符合您的期望。您可能应该使用其他内容，例如map运算符。
public Mono<Void> addEvent(Mono<Event> event){
return event
.filter(event -> event.getID()!= null)
.switchIfEmpty(Mono.error(new BadRequestException("ID shouldn't be null!")))
.publishOn(Schedulers.parallel())
.map(event -> {
// if this throws an exception, this will be turned into an error message
eventRepository.save(event);
return event;
})
.then();
现在，我们提到的是：
调度程序/执行器不会停止尝试将实体持久存储到数据库中
查看您的日志，看来Hikari池正在重试连接数据库。一旦达到连接超时，池就会引发错误并触发Mono.error。在后台，Hikari似乎仍在尝试重新连接（可能具有指数补偿），因为这是它的工作。您正在查看的线程不是调度程序中的线程，而是连接池中的线程。
关于您的代码段的其他一些注意事项：
switchIfEmpty(Mono.error(new BadRequestException("ID shouldn't be null!")))有效地将一个空的Mono（如果id为null）转换为错误信号。当错误信号流过链条时，将不会调用doOnNext。doOnError(e -> Mono.error(new PersistenceException("Persistence failed....")))不会做您认为应该做的事；同样，这是一个副作用方法，因此不会将错误转换为持久性异常。在此处，您应该只记录错误，而不要采取措施。onErrorResume用于在发生错误的情况下切换到后备方法