The method next() is undefined for the type Object ?

Question

package com.test1; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.Vector; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTable; public class Test2 extends JFrame{ Vector rowData,columnNames; JTable jt = null; JScrollPane jsp = null; PreparedStatement ps = null; Connection ct=null; ResultSet rs=null; public static void main(String[] args) { // TODO Auto-generated method stub } public Test2(Object rs, Object ps, Object ct){ columnNames = new Vector(); columnNames.add("学号"); columnNames.add("名字"); columnNames.add("性别"); columnNames.add("年龄"); columnNames.add("籍贯"); columnNames.add("系别"); rowData = new Vector(); try { Class.forName("com.mysql.jdbc.Driver"); ct = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3066/" + "book?CharacterEncoding=gbk","root","root"); ps = ((Connection) ct).prepareStatement("select * from stu"); rs = ((PreparedStatement) ps).executeQuery(); //标记A,next下划线报错,The method getString(int) is undefined for the type Object //标记B,getString下划线报错,连续4行,The method getString(int) is undefined for the type Object while(rs.next()){ Vector hang = new Vector(); hang.add( rs.getString(1)); hang.add(rs.getString(2)); hang.add(rs.getString(3)); hang.add(rs.getInt(4)); hang.add(rs.getString(5)); hang.add( rs.getString(6)); rowData.add(hang); } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); //标记C, .close报错,The method close() is undefined for the type Object }finally{ try{ if(rs!=null ) rs.close(); if(ps!=null) ps.close(); if(ct!=null) ct.close(); }catch (Exception e){ e.printStackTrace(); } } jt = new JTable(rowData,columnNames); jsp = new JScrollPane(jt); this.add(jsp); this.setSize(400, 350); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.setVisible(true); } } 无法上传图片,标记A标记B标记C,跟着教程码的,教材没报错,很久了没解决,谢谢,

Answer 1

public Test2(Object rs, Object ps, Object ct)
替换为
public Test2(ResultSet rs, PreparedStatement ps, Connection ct)