标签：jdbc java mchange ConnectionImpl 低报 版本 mysql com

详细错误：

 1 java.sql.SQLException: Unknown system variable 'query_cache_size'
 2     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:959)
 3     at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3870)
 4     at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3806)
 5     at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2470)
 6     at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2617)
 7     at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2546)
 8     at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2504)
 9     at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1370)
10     at com.mysql.jdbc.ConnectionImpl.loadServerVariables(ConnectionImpl.java:3861)
11     at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3289)
12     at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2298)
13     at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2084)
14     at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:795)
15     at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
16     at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
17     at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
18     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
19     at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
20     at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
21     at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400)
22     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327)
23     at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175)
24     at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
25     at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
26     at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
27     at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
28     at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
29     at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
30     at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
31     at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)

原因：mysql驱动版本过低，更换驱动版本

 <!-- mysql -->
 <dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
     <version>8.0.16</version>
 </dependency>

标签：jdbc,java,mchange,ConnectionImpl,低报,版本,mysql,com
来源： https://www.cnblogs.com/maigy/p/12230823.html

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