老师 无法连接数据库

import org.junit.Test;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import static java.lang.Class.forName;

public class jdbc {
   @Test
   public void select(){

       try {
           Class.forName("com.mysql.jdbc.Driver");
           Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbc","root","12345678");
           String sql = "select * from good where price <=3500";
           Statement stmt = con.createStatement();
           ResultSet resultSet = stmt.executeQuery(sql);
           while(resultSet.next()){
               int id =resultSet.getInt("id");
               String name = resultSet.getString("name");
               float price = resultSet.getFloat("price");
               String desp = resultSet.getString("desp");
               System.out.println(id +" "+name+" "+price+" "+desp);
           }
       } catch (Exception e) {
           e.printStackTrace();
       }
   }


}