每次开机第一次启动项目的时候，总会报错 ，需要启动好多次才能登录，为什么呢

at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110)

at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)

at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)

at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)

at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)

at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)

at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199)

at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)

at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)

at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)

at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)

at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

四月 19, 2020 8:35:32 上午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run

警告: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@476c163d -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 

java.sql.SQLNonTransientConnectionException: Public Key Retrieval is not allowed

at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110)

at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)

at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)

at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)

at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)

at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)

at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199)

at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)

at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)

at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)

at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)

at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

四月 19, 2020 8:35:32 上午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run

警告: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@7aa76586 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 

java.sql.SQLNonTransientConnectionException: Public Key Retrieval is not allowed

at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110)

at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)

at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)

at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)

at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)

at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)

at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199)

at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)

at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)

at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)

at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)

at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

java.sql.SQLException: Connections could not be acquired from the underlying database!

at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)

at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)

at com.imooc.utils.JDBCUtils.getConnection(JDBCUtils.java:24)

at com.imooc.dao.impl.UserDaoImpl.login(UserDaoImpl.java:20)

at com.imooc.service.impl.UserServiceImpl.login(UserServiceImpl.java:15)

at com.imooc.web.action.UserServlet.login(UserServlet.java:63)

at com.imooc.web.action.UserServlet.doGet(UserServlet.java:27)

at com.imooc.web.action.UserServlet.doPost(UserServlet.java:79)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at com.imooc.web.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:24)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:543)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)

at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:688)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)

at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:609)

at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)

at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:818)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1623)

at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.lang.Thread.run(Thread.java:745)

Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.

at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)

at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)

at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)

... 34 more