java 连接MySQL失败问题

末蓝、 2022-03-10 00:23 203阅读 0赞

错误如下：

Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.

at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)  
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)  
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)  
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77)  
    at UserTest.test1(UserTest.java:38)  
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)  
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)  
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)  
    at java.lang.reflect.Method.invoke(Method.java:498)  
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)  
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)  
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)  
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)  
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)  
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)  
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)  
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)  
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)  
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)  
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)  
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)  
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)  
    at org.junit.runner.JUnitCore.run(JUnitCore.java:157)  
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)  
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)  
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)  
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)  
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.  
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)  
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)  
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)  
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)  
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)  
    at com.mysql.jdbc.Util.getInstance(Util.java:387)  
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:917)  
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:896)  
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:885)  
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)  
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2332)  
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2085)  
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:795)  
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)  
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)  
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)  
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)  
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)  
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)  
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400)  
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327)  
    at java.sql.DriverManager.getConnection(DriverManager.java:664)  
    at java.sql.DriverManager.getConnection(DriverManager.java:208)  
    at org.apache.ibatis.datasource.unpooled.UnpooledDataSource.doGetConnection(UnpooledDataSource.java:201)  
    at org.apache.ibatis.datasource.unpooled.UnpooledDataSource.doGetConnection(UnpooledDataSource.java:196)  
    at org.apache.ibatis.datasource.unpooled.UnpooledDataSource.getConnection(UnpooledDataSource.java:93)  
    at org.apache.ibatis.datasource.pooled.PooledDataSource.popConnection(PooledDataSource.java:404)  
    at org.apache.ibatis.datasource.pooled.PooledDataSource.getConnection(PooledDataSource.java:90)  
    at org.apache.ibatis.transaction.jdbc.JdbcTransaction.openConnection(JdbcTransaction.java:139)  
    at org.apache.ibatis.transaction.jdbc.JdbcTransaction.getConnection(JdbcTransaction.java:61)  
    at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:338)  
    at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:84)  
    at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62)  
    at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:326)  
    at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)  
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)  
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83)  
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)  
    ... 25 more  
Caused by: java.lang.NullPointerException  
    at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:3005)  
    at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1916)  
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1845)  
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1215)  
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2255)  
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2286)  
    ... 52 more

原因是：mysql 驱动版本和mysql 数据库版本对不上导致。将MySQL驱动版本修改和MySQL数据库版本一致即可。