在ubuntu 18.04中通过eclipse使用mySql（mysql 5.7.22）进行JDBC连接时出错[重复]

Question

请帮助解决这个错误。同样的代码在windows中运行良好。但是我不明白为什么它不能在Linux(Ubuntu 18.04)上运行。

以下代码：

 import java.sql.*;
public class HelloWorld {

    public static void main(String[] args) {
        Connection con = null;
        Statement st = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb","root","root");
            String sql = "insert into mytable values('[e-mail]','amit1234')";
            st = con.createStatement();
            int x = st.executeUpdate(sql);
            if(x==1) {
                System.out.println("Record inserted");
            }else {
                System.out.println("Record not inserted");
            }
        }catch(Exception e) {
            e.printStackTrace();
        }finally {
            try {
                if(st!=null)st.close();
                if(con!=null)con.close();
            }catch(Exception e) {
                e.printStackTrace();
            }
        }
    }  
}  

运行代码时引发此异常：

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
Sat Jul 07 12:52:40 IST 2018 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
java.sql.SQLException: Access denied for user 'root'@'localhost'
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:127)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:95)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:862)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at com.amitsingh.HelloWorld.main(HelloWorld.java:10)

Answer 1

也许用户root没有足够的权限从localhost连接。您可以通过命令行/shell选中此项以连接到数据库。使用以下命令进行连接：

mysql --host=localhost --user=root --password=root mydb

如果连接不成功，则应更新用户凭据。

出于测试目的，您可以将所有权限授予用户。这可以在连接到mysql后完成。

GRANT ALL PRIVILEGES ON mydb.* TO 'root'@'%' WITH GRANT OPTION;