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

问题描述

我是数据库新手，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.遵循多个新手指南如何开始.

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.

原来是这样.我在本地主机上有数据库，并通过工作台和 Windows 提示成功连接到它.但是在我用java执行代码之后:

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:无法创建到数据库服务器的连接.

为什么会发生?我试图重新安装 MySQL，清理操作系统变量，到处寻找，但找不到解决方案.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.

更新:

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 的兼容性.您需要升级到 MySQL Connector/J 5.1.46 或 - 更好- 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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