Unable to open JDBC Connection for DDL execution

Question

你好 老师：
我这里有两个问题：
1、在实现访问数据库过程中 数据库经常报出了
错误信息：The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

2、无法访问数据库
错误信息：org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘entityManagerFactory’ defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to open JDBC Connection for DDL execution

Answer 1

提问者 慕粉0349399301 2020-08-30 00:52:08

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_181]

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_181]

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_181]

at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_181]

at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.15.jar:8.0.15]

at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105) ~[mysql-connector-java-8.0.15.jar:8.0.15]

at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151) ~[mysql-connector-java-8.0.15.jar:8.0.15]

at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167) ~[mysql-connector-java-8.0.15.jar:8.0.15]

at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:91) ~[mysql-connector-java-8.0.15.jar:8.0.15]

at com.mysql.cj.NativeSession.connect(NativeSession.java:152) ~[mysql-connector-java-8.0.15.jar:8.0.15]

at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:955) ~[mysql-connector-java-8.0.15.jar:8.0.15]

at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825) ~[mysql-connector-java-8.0.15.jar:8.0.15]

... 49 common frames omitted

Caused by: java.net.ConnectException: Connection refused: connect

at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) ~[na:1.8.0_181]

at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85) ~[na:1.8.0_181]

at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_181]

at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_181]

at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_181]

at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) ~[na:1.8.0_181]

at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_181]

at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_181]

at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155) ~[mysql-connector-java-8.0.15.jar:8.0.15]

at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:65) ~[mysql-connector-java-8.0.15.jar:8.0.15]

... 52 common frames omitted