1.Unknown character set: 'utf8mb4'连接的程序为: package qdu.wxyz.db;
import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException;
public class Conn { static Connection conn; public Conn(){ conn=null; } public Connection getConnection(){ try { Class.forName("com.mysql.jdbc.Driver"); conn= DriverManager.getConnection("jdbc:mysql://localhost:3306/wxyz?useUnicode=true&characterEncoding=utf-8", "ximo","ximo");//url,username,password; //System.out.println(conn+"123"); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } //连接数据库 catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return conn; } }
用户名密码没有错误,运行出错 解决方案:驱动用错了,版本不同就会有这种错误,修改后版本对应为》mysql5.6 对应mysql-connertor-java-5.1.30-bin.jar >>mysql6.0对应mysql-connertor-java-5.1.8-bin.jar
2.如果是用户密码错误,可以使用指令: 查看MYSQL数据库中所有用户 mysql> SELECT DISTINCT CONCAT('User: ''',user,'''@''',host,''';') AS query FROM mysql.user;
然后权限的指令为: 查看数据库中具体某个用户的权限 mysql> show grants for 'cactiuser'@'%';
mysql> select * from mysql.user where user='cactiuser' /G
查看user表结构 需要具体的项可结合表结构来查询 mysql> desc mysql.user; |