在java删除数据库数据失败怎么回事

Question

1. public int delete(Student student){
   //建立一个DBOperation，通过这个对象完成数据库的连接操作
   DBOperation dboperation= new DBOperation();
   //获取数据库连接
   Connection connection=null;
   try{
   connection=dboperation.getConnection();

       String sql="delete from student where stuId='?'";
       PreparedStatement pst=connection.prepareStatement(sql);
       pst.setString(1, student.getStuId());
       pst.execute();
        /* Statement st=connction.createStatement();
          //字符串拼接
          String sql="delete from student where Stuid='"+student.getStuid()+"'";
          st.execute(sql);*/
       System.out.println(sql);
       return 0;
   }catch(Exception ex){
       ex.printStackTrace();
       //返回上层判断
       return -1;
   }finally{
       dboperation.closeConnect(connection);
   }
   

   }
   2.package edu.jmi.xyh.view;

import java.awt.BorderLayout;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import java.awt.Font;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JPasswordField;

import edu.jmi.xyh.bean.Student;
import edu.jmi.xyh.dao.StudentDao;

public class DeleteView extends JFrame {

private JPanel contentPane;
private JTextField txID;
private JTextField txName;
private JPasswordField txPw;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                DeleteView frame = new DeleteView();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the frame.
 */
public DeleteView() {
    setTitle("\u5220\u9664\u5B66\u751F\u4FE1\u606F");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 450, 300);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);

    JLabel label = new JLabel("\u5220 \u9664 \u5B66 \u751F \u4FE1 \u606F");
    label.setFont(new Font("宋体", Font.PLAIN, 16));
    label.setBounds(140, 22, 147, 15);
    contentPane.add(label);

    JLabel lblId = new JLabel("\u7528 \u6237 ID\uFF1A");
    lblId.setBounds(95, 55, 69, 15);
    contentPane.add(lblId);

    txID = new JTextField();
    txID.setBounds(174, 52, 113, 21);
    contentPane.add(txID);
    txID.setColumns(10);

    JLabel label_2 = new JLabel("\u7528 \u6237 \u540D\uFF1A");
    label_2.setBounds(95, 98, 66, 15);
    contentPane.add(label_2);

    JLabel label_3 = new JLabel("\u5BC6   \u7801\uFF1A");
    label_3.setBounds(95, 143, 54, 15);
    contentPane.add(label_3);

    txName = new JTextField();
    txName.setBounds(174, 95, 113, 21);
    contentPane.add(txName);
    txName.setColumns(10);

    JButton button = new JButton("\u5220\u9664");
    button.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            //完成注册功能
            String id=txID.getText();
            if(id==null||id.length()==0||id.length()>20){
                JOptionPane.showMessageDialog(null, "ID输入不正确！");
            }
            //继续验证用户名和密码
            String pw=txPw.getText();
            String name=txName.getText();
            Student student=new Student();

            student.setStuId(id);
            student.setStuName(name);
            student.setStuPwd(pw);
            StudentDao studentDao=new StudentDao();
            int result=studentDao.delete(student);
            if(result==0){
                JOptionPane.showMessageDialog(null, "删除成功！");

            }
            else{
                JOptionPane.showMessageDialog(null, "删除失败！");


            }
            System.out.println("id="+id+"pw="+pw);


        }
    });
    button.setBounds(75, 189, 93, 23);
    contentPane.add(button);

    JButton button_1 = new JButton("\u53D6\u6D88");
    button_1.setBounds(232, 189, 93, 23);
    contentPane.add(button_1);

    txPw = new JPasswordField();
    txPw.setBounds(174, 140, 113, 21);
    contentPane.add(txPw);
}

}

Parameter index out of range (1 > number of parameters, which is 0)

Answer 1

String sql="delete from student where stuId='?'";
这个地方把问号的单引号去掉 试试