我有一个连接到mysql的spring boot应用程序，我使用spring data jpa。 使用的依赖项是，
1) "org.springframework.data:spring-data-jpa:2.6.1",
2) "org.springframework.boot:spring-boot-starter-data-jpa:2.5.14
3) "mysql:mysql-connector-java"
它工作正常，但是当添加这两个额外的依赖项时，它会崩溃，并且我不断收到以下异常， 4）“org.springframework.boot：spring-boot-starter-data-cassandra：2.7.9”， 5）“org.springframework.data：spring-data-cassandra：3.4.8”
[main] ERROR com.zaxxer.hikari.pool.HikariPool - HikariPool-1 - Exception during pool initialization.
java.sql.SQLNonTransientConnectionException: Too many connections
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:833)
at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:453)
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246)
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:198)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138)
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358)
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206)
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477)
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560)
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115)
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112)
at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcEnvironmentInitiator.java:180)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:68)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:101)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:152)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:176)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:127)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1224)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1255)
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1863)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:908)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:453)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:343)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1370)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1359)
at com.roku.ads.marketing.connector.Application.main(Application.java:24)
我尝试在属性文件中设置 spring.datasource.hikari.maximum-pool-size=10 但没有帮助。
默认情况下，它仅为默认数据源实现 1 个连接 (
spring.datasource参考这篇文章：https://www.baeldung.com/spring-data-jpa-multiple-databases
这不是卡桑德拉，但和你的问题一样。