问题遇到的现象和发生背景
运行程序后 想要打开界面 但是无法连接 报错如下
问题相关代码，请勿粘贴截图
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.GeneratedConstructorAccessor41.newInstance(Unknown Source) ~[na:na]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_333]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_333]
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.20.jar:8.0.20]
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105) ~[mysql-connector-java-8.0.20.jar:8.0.20]
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151) ~[mysql-connector-java-8.0.20.jar:8.0.20]
at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167) ~[mysql-connector-java-8.0.20.jar:8.0.20]
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:91) ~[mysql-connector-java-8.0.20.jar:8.0.20]
at com.mysql.cj.NativeSession.connect(NativeSession.java:144) ~[mysql-connector-java-8.0.20.jar:8.0.20]
at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:956) ~[mysql-connector-java-8.0.20.jar:8.0.20]
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) ~[mysql-connector-java-8.0.20.jar:8.0.20]
6 common frames omitted
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method) ~[na:1.8.0_333]
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:75) ~[na:1.8.0_333]
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:476) ~[na:1.8.0_333]
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:218) ~[na:1.8.0_333]
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:200) ~[na:1.8.0_333]
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:162) ~[na:1.8.0_333]
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:394) ~[na:1.8.0_333]
at java.net.Socket.connect(Socket.java:606) ~[na:1.8.0_333]
at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155) ~[mysql-connector-java-8.0.20.jar:8.0.20]
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:65) ~[mysql-connector-java-8.0.20.jar:8.0.20]
9 common frames omitted
