java.sql.SQLNonTransientConnectionException: Could not connect to address=(host=localhost)(port=3306)(type=master) : Socket fail to connect to host:localhost, port:3306. Connection refused: connect at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.createException(ExceptionFactory.java:73) ~[mariadb-java-client-2.7.5.jar:na] at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.create(ExceptionFactory.java:197) ~[mariadb-java-client-2.7.5.jar:na] at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connectWithoutProxy(AbstractConnectProtocol.java:1394) ~[mariadb-java-client-2.7.5.jar:na] at org.mariadb.jdbc.internal.util.Utils.retrieveProxy(Utils.java:635) ~[mariadb-java-client-2.7.5.jar:na] at org.mariadb.jdbc.MariaDbConnection.newConnection(MariaDbConnection.java:150) ~[mariadb-java-client-2.7.5.jar:na] at org.mariadb.jdbc.Driver.connect(Driver.java:89) ~[mariadb-java-client-2.7.5.jar:na] at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:364) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:476) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:561) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) ~[HikariCP-4.0.3.jar:na] at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcEnvironmentInitiator.java:181) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:68) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:101) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:175) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:173) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:127) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1460) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1494) ~[hibernate-core-5.6.8.Final.jar:5.6.8.Final] at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) ~[spring-orm-5.3.19.jar:5.3.19] at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.3.19.jar:5.3.19] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409) ~[spring-orm-5.3.19.jar:5.3.19] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396) ~[spring-orm-5.3.19.jar:5.3.19] at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.3.19.jar:5.3.19] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1863) ~[spring-beans-5.3.19.jar:5.3.19] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800) ~[spring-beans-5.3.19.jar:5.3.19] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620) ~[spring-beans-5.3.19.jar:5.3.19] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.19.jar:5.3.19] at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.19.jar:5.3.19] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.19.jar:5.3.19] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.19.jar:5.3.19] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.19.jar:5.3.19] at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154) ~[spring-context-5.3.19.jar:5.3.19] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:908) ~[spring-context-5.3.19.jar:5.3.19] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.19.jar:5.3.19] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.7.jar:2.6.7] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:740) ~[spring-boot-2.6.7.jar:2.6.7] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:415) ~[spring-boot-2.6.7.jar:2.6.7] at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) ~[spring-boot-2.6.7.jar:2.6.7] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1312) ~[spring-boot-2.6.7.jar:2.6.7] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301) ~[spring-boot-2.6.7.jar:2.6.7]

Caused by: java.sql.SQLNonTransientConnectionException: Socket fail to connect to host:localhost, port:3306. Connection refused: connect at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.createException(ExceptionFactory.java:73) ~[mariadb-java-client-2.7.5.jar:na] at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.create(ExceptionFactory.java:188) ~[mariadb-java-client-2.7.5.jar:na] at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.createSocket(AbstractConnectProtocol.java:257) ~[mariadb-java-client-2.7.5.jar:na] at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.createConnection(AbstractConnectProtocol.java:524) ~[mariadb-java-client-2.7.5.jar:na] at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connectWithoutProxy(AbstractConnectProtocol.java:1389) ~[mariadb-java-client-2.7.5.jar:na] ... 49 common frames omitted

Caused by: java.net.ConnectException: Connection refused: connect at java.base/java.net.PlainSocketImpl.waitForConnect(Native Method) ~[na:na] at java.base/java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:107) ~[na:na] at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:412) ~[na:na] at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:255) ~[na:na] at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:237) ~[na:na] at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:na] at java.base/java.net.Socket.connect(Socket.java:609) ~[na:na] at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.createSocket(AbstractConnectProtocol.java:252) ~[mariadb-java-client-2.7.5.jar:na] ... 51 common frames omitted

에러 원인

3306 port를 이미 다른 앱이 사용하고 있어서 나는 오류

해결 방법

1. port 번호를 바꿈

혹은

2. 3306 port를 사용하고 있는 앱을 종료