无法创建与数据库服务器的连接。 强、jdbc、mysql数据库

Question

MySQL 服务器托管在 ubuntu 服务器 vm @ 10.0.0.200 上，ssh 端口位于 3333。

尝试启动 spring boot 应用程序给了我这个错误：

java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.

我的 application.properties 看起来像这样：

spring.datasource.url = jdbc:mysql://10.0.0.200:3306/test?useSSL=false&allowPublicKeyRetrieval=true&autoReconnect=true
spring.datasource.username = boss
spring.datasource.password = StrongPass123!
spring.jpa.show-sql= true
spring.jpa.hibernate.ddl-auto= update
spring.jpa.properties.hibernate.dialect= org.hibernate.dialect.MySQL5Dialect

我在想也许我需要为我的虚拟机指定 ssh 端口并尝试过：

spring.datasource.url = jdbc:mysql://{10.0.0.200:3333}:3306/test?useSSL=false&allowPublicKeyRetrieval=true&autoReconnect=true

并得到同样的错误。 我尝试将my.cnf中mysql的绑定地址设置为我的vm的IP（localhost）。 无济于事。

我确信凭据是正确的，但还没有让春天正确启动。

错误跟踪：

java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
        at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110) ~[mysql-connector-java-8.0.29.jar:8.0.29]
        at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.29.jar:8.0.29]
        at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.29.jar:8.0.29]
        at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.29.jar:8.0.29]
        at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.29.jar:8.0.29]
        at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:898) ~[mysql-connector-java-8.0.29.jar:8.0.29]
        at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:823) ~[mysql-connector-java-8.0.29.jar:8.0.29]
        at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:448) ~[mysql-connector-java-8.0.29.jar:8.0.29]  
        at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:241) ~[mysql-connector-java-8.0.29.jar:8.0.29]
        at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:198) ~[mysql-connector-java-8.0.29.jar:8.0.29]
        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-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcEnvironmentInitiator.java:181) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:68) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:101) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) 
~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:175) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) 
~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:173) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]
        at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:127) ~[hibernate-core-5.6.9.Final.jar:5.6.9.Final]

Answer 1

为了解决 SQLNonTransientConnectionException 错误，我首先建议使用此处找到的旧 stackoverflow 帖子中的策略： SQLNonTransientConnectionException: No current connection, in my application while intering with Derby database

如果这不起作用，那么我会在此之后尝试在 application.properties 代码中对您的代码进行建模：

 spring.jpa.hibernate.ddl-auto=update spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/db_example spring.datasource.username=springuser spring.datasource.password=ThePassword spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver #spring.jpa.show-sql: true

我在https://spring.io/guides/gs/accessing-data-mysql/的 application.properties 属性部分找到了它。 因此，该信息直接来自源头。 如果您可以使用 Springs 标准示例中的结构，则可以一一添加其他属性，在测试连接之前再次构建并重新运行代码。

有时完全关闭您的 IDE，然后重新打开它也会有所帮助。