Question

我有以下代码：

package connectivity;

import java.sql.ResultSet;
import java.sql.Statement;

public class Connectivity {

    public static void main(String[] args) {
       cls o=new cls();
       try{
            Statement s=o.getct();
             ResultSet rs;

            rs=s.executeQuery("select * from REGISTRATION1");
           while(rs.next()){
                String st=rs.getString("FACULTY_ID");
                String st2=rs.getString("STUDENT_ID");


             }

        }catch(Exception e){
            System.out.println(e);
        }
    }
}

输出结果为：

java.sql.SQLException:
[Microsoft][ODBC SQL Server Driver]Invalid Descriptor Index"

为什么？

Answer 1

请解释方法getct（）中的连接语句？确保你已添加库中的mysql-connector-java-xyz-bin jar文件。以下代码可能会有所帮助：

   public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;

        try {

            Class.forName("com.mysql.jdbc.Driver").newInstance();
            System.out.println("Driver Setup");

        String connectionUrl = "jdbc:mysql://localhost:3306/db";
            String connectionUser = "root";
            String connectionPassword = "";//password if any
            conn = DriverManager.getConnection(connectionUrl, connectionUser, connectionPassword);
            System.out.println("Connection setup");
            stmt = (Statement) conn.createStatement();
            rs = stmt.executeQuery("SELECT * FROM table_name");
            while (rs.next()) {
                String col1 = rs.getString("column1name");
                String col2 = rs.getString("column2name");

                System.out.println("First Value"+col1+"Second Value"+col2);
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

 }

Answer 2

看起来FACULTY_ID或STUDENT_ID不存在。请检查ResultSet中列的名称或尝试按索引读取。

为什么我无法连接到我的数据库？

2 个答案: