com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException:无法创建与数据库服务器的连接 [英] com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server

问题描述

我是数据库的新手，刚开始学习它们.我有MySQL Server 8.0，Workbench 8.0，Java连接器5.1.31，Java 1.8本身.按照新手入门指南进行操作.

I'm new in Databases just started to learn them. I have MySQL Server 8.0., Workbench 8.0, Java connector 5.1.31, Java 1.8 itself. Followed multiple guides for newbies how to start with.

有这种情况.我在本地主机上有数据库，并通过工作台并通过Windows提示符成功连接到它.但是，当我在Java中执行代码后:

So there is the case. I have database on localhost and successfully connect to it with workbench and via windows prompt. But after I execute code in java:

        Driver sqlDriver = new FabricMySQLDriver();
        DriverManager.registerDriver(sqlDriver);
        Connection sqlConnection = DriverManager.getConnection("jdbc:mysql://localhost:3306/?user=root", "root", "root");

我收到异常com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.

为什么会发生?我试图重新安装MySQL，清除OS变量，到处都找不到解决方案.很高兴在这里找到它.

Why it could happen? I've tried to reinstall MySQL, Cleaned OS variables, looked everywhere and couldn't find solution. Would be glad to find it here.

UPD:

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
    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:408)
    at com.mysql.jdbc.Util.getInstance(Util.java:383)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1023)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:997)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:983)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:928)
    at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2407)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2328)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:832)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
    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:408)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:417)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at com.company.Main.main(Main.java:11)
Caused by: java.lang.NullPointerException
    at com.mysql.jdbc.ConnectionImpl.getServerCharacterEncoding(ConnectionImpl.java:3309)
    at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1985)
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1911)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1288)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2508)
    at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2346)
    ... 13 more

推荐答案

问题是旧版本的MySQL Connector/J与MySQL 8兼容.您需要升级到MySQL Connector/J 5.1.46或更高版本-8.0.11(或更高版本).

The problem is the compatibility of older versions of MySQL Connector/J with MySQL 8. You need to upgrade to either MySQL Connector/J 5.1.46 or - better - 8.0.11 (or a higher version).

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