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问题：

Spring Webflux（Reactor）调度程序在错误后不会终止

伍溪叠
2023-03-14

我是Spring WebFlux/Reactive编程的新手，我在调度器任务方面遇到了一些问题：

发生错误后，调度器（执行器线程）不会终止，例如，当试图使用schedulers.parallel（）线程将实体保存到脱机的数据库时。

我的代码实际上是这样的：

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()));
            });
}

然而，当数据库脱机时，i会将错误消息打印到控制台，但调度器/执行器不会停止将实体持久化到数据库中的尝试。过程继续进行，错误信息一次又一次地打印到控制台...

如果发生错误，我如何告诉调度器/执行器停止，这样当发生错误时，这些线程不会永远运行？

以及如何在数据库再次联机时自动重新启动这些调度器/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,似乎不会再次执行.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]

看起来，如果我的数据库关闭，Hikari线程不会停止建立连接。但是，当我再次重新启动数据库时，错误日志记录似乎停止了，持久性操作也没有执行。

在数据库脱机时，是否可以停止重新建立连接进程，以避免浪费资源？

共有1个答案

皇甫文乐
2023-03-14

对于project reactor，doon***运算符是“副作用”运算符，您不应该在这些运算符中实现业务逻辑或I/O操作。

在这种情况下，我相信您的存储库调用抛出的异常没有在反应链中转换成错误信号。这就解释了为什么它的行为不是你所期望的。您可能应该使用其他东西，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，我们要说的是：

关于代码段的其他一些注意事项：

  • 您应该不惜一切代价避免在反应性应用程序中使用阻塞库。您几乎失去了使用反应编程的所有好处。
  • switchifEmpty（Mono.error（new BadRequestException（“id不应该为null！”））有效地将空的Mono（在此id为null的情况下）转换为错误信号。当错误信号流过链时，将不会调用doonnext。
  • doonerror(e->mono.error(new PersistenceException（“persistence failed....”））)不会执行您认为它应该执行的操作；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。在其中，您应该只记录错误，而不是对其执行操作。
  • OnErrorResume用于在发生错误时切换到回退方法
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