MySQL 拒绝了我从 Java 程序而不是命令行的访问

Question

我在 Ubuntu 14.04 机器上安装了 MySQL。我可以从命令行使用 root 登录。但是当我运行下面的java程序时，我收到了拒绝访问的异常。怎么了？

import java.sql.Connection;
import java.sql.DriverManager;

public class Conn {
    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.jdbc.Driver");
        Connection conn = DriverManager.getConnection("jdbc:mysql://"
            + "localhost" + "/xi_tong?characterEncoding=utf8", "root",
            "****");
    }
}

异常：

Exception in thread "main" java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3970)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3906)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:873)
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1710)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1226)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2253)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2284)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2083)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:806)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:410)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:328)
    at java.sql.DriverManager.getConnection(DriverManager.java:571)
    at java.sql.DriverManager.getConnection(DriverManager.java:215)
    at Conn.main(Conn.java:7)

我可以从命令行登录：

zirui@52:~$ mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 104
Server version: 5.5.55-0ubuntu0.14.04.1 (Ubuntu)

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input 
statement.

mysql>

在另一台机器上：

zirui@45:~/Server/src$ java -cp .:mysql-connector-java-5.1.40-bin.jar Conn
zirui@45:~/Server/src$

Answer 1

确保数据库存在。

USE yourdb;

我最近遇到了这样的问题，其中 dbname 输入错误。

Answer 2

问题出在权限上！

MySQL 拒绝了我从 Java 程序而不是命令行的访问

MySQL denied my access from a Java program but not from command line

java

mysql

access-denied