JDBC连接数据库

import java.sql.Connection;

import java.sql.DriverManager;
import java.sql.Statement;

public class Jdbc {
    public static void main(String[] args) throws Exception {
        String url = "jdbc:mysql://localhost:3306/bank";
        String username = "root";
        String password = "123456";
        Connection conn = DriverManager.getConnection(url,username,password);
        String sql = "update stu set id = 1 where name = '马运'";
        Statement stmt = conn.createStatement();
        int count = stmt.executeUpdate(sql);
        System.out.println(count);
        stmt.close();
        conn.close();
    }
}

我出错的地方，一个是把表的名字写到了数据库该写的地方，还有就是SQL语句的正确使用