Question

我在linux machiche上设置了mysql（mariadb）。我创建了一个用户'newuser'，如：

CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON * . * TO 'newuser'@'localhost';

当我这样做时：

select user,password from user;

我可以看到：

+--------------+-------------------------------------------+
| user         | password                                  |
+--------------+-------------------------------------------+
| root         | *password                                 |
| newuser      | *password                                 |
+--------------+-------------------------------------------+

当我执行此命令时：

select user();

+----------------+
| user()         |
+----------------+
| root@localhost |
+----------------+

我正在尝试使用java连接到我的数据库，但我得到以下异常：

java.sql.SQLException: Cannot create connection:Access denied for user 'newuser'@'localhost' (using password: YES)

+------------------------------------------------------------------------------------------------------------------------------------------------+
| Grants for newuser@localhost                                                                                                              |
+------------------------------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'newuser'@'localhost' IDENTIFIED BY PASSWORD '*7ABDF971526E9441B919C9FE77D50DB0363B3509' WITH GRANT OPTION |
+------------------------------------------------------------------------------------------------------------------------------------------------+

连接到db的Java代码：

try {
        Class.forName("com.mysql.jdbc.Driver");
    //  Connection connection = DriverManager.getConnection(connectionString);
        Connection connection = DriverManager.getConnection("jdbc:mariadb://localhost:3306/iot?autoReconnect=true","newuser","password");
        System.out.println("Connected --->"  + connection);
        return connection;
    } catch (SQLException e) {
        throw new SQLException("Cannot create connection:" + e.getMessage());
    }

任何人都可以帮助我，我错过了吗？

Answer 1

尝试连接到mysql并执行

update user set host = '%' where user = 'newuser';
flush privileges;

尝试再次连接。如果你成功了（我怀疑）你没有在与mysql相同的机器上运行代码。你需要找到本地机器的ip（linux上的ifconfig，windows上的ipconfig）并执行

update user set host = 'xxx.xxx.xxx.xxx.' where user = 'newuser';
flush privileges;

仅允许来自ip（xxx.xxx.xxx.xxx）的连接。

要还原更改，请执行

update user set host = 'localhost' where user = 'newuser';
flush privileges;

Answer 2

你真的从本地机器连接？如果没有，您应该将“localhost”替换为您的主机的描述。

Answer 3

根据您的情况，我认为您应该使用

    FLUSH PRIVILEGES;

如果修改了权限，则不需要FLUSH，因为它将被重新加载，但在这里您要创建新用户并向新用户授予新权限，因此请尝试使用FLUSH PRIVILEGES。

我已经使用了以下步骤，它在这里工作正常： -

CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON * . * TO 'newuser'@'localhost';
FLUSH PRIVILEGES;

现在使用新用户登录： -

     mysql -u newuser -p
     password
     show GRANTS;

    Output:- 
    +------------------------------------------------------+
    | Grants for newuser@localhost                         |
    +------------------------------------------------------+
    | GRANT ALL PRIVILEGES ON *.* TO 'newuser'@'localhost' |
    +------------------------------------------------------+

作为select user（） - 它将显示已登录的当前用户 SELECT User FROM mysql.user ---它将显示在mysql中创建的所有用户。

    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        try {
            Class.forName("com.mysql.jdbc.Driver");
        //  Connection connection = DriverManager.getConnection(connectionString);
            Connection connection = DriverManager.getConnection("jdbc:mariadb://localhost:3306/iot?autoReconnect=true","newuser","password");
            System.out.println("Connected --->"  + connection);
        } catch (SQLException e) {
            throw new SQLException("Cannot create connection:" + e.getMessage());
        } 

        }

它运行没有错误。我在这里看不到任何问题。看看它。

无法以编程方式连接到mysql

3 个答案: