数据库错误
java.sql.SQLException: Driver:com.mysql.jdbc.Driver@332820f4 returned null for URL:jdbc;mysql://127.0.0.1:3306/mydb
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:329) ~[tomcat-jdbc-8.5.14.jar:na]
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203) ~[tomcat-jdbc-8.5.14.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:735) [tomcat-jdbc-8.5.14.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:667) [tomcat-jdbc-8.5.14.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:482) [tomcat-jdbc-8.5.14.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:154) [tomcat-jdbc-8.5.14.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118) [tomcat-jdbc-8.5.14.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107) [tomcat-jdbc-8.5.14.jar:na]
