Java SQL 语句 - 索引数组越界

Question

嗨，我当前有一个正在尝试运行的查询，但是每次我尝试运行此查询时，我都会得到一个数组索引越界，我不确定为什么这是因为我没有在其中声明任何数组我的代码，有人可以帮忙吗？

public void actionPerformed(ActionEvent argO) {

    try{
        String query="select * from Users where Username ='admin' and password='password2'  ";
        PreparedStatement pst=connection.prepareStatement(query);
        pst.setString(1, text_username.getText());
        pst.setString(2, passwordField.getText());

        ResultSet rs=pst.executeQuery();
        int count=0;
        while(rs.next())
        {
            count=count+1;

        }
        if(count==1)
        {
            JOptionPane.showMessageDialog(null, "Username and password is correct");
            frmMychatApp.dispose();
            AdminPage admin = new AdminPage();
            admin.setVisible(true);
        }
        else if(count>1)
        {
            JOptionPane.showMessageDialog(null, "Duplicate Username and password");
        }
        else{
            JOptionPane.showConfirmDialog(null, "Username and password is not correct. Please Try Again");
        }

        rs.close();
        pst.close();
    }catch (Exception e)
    {
        JOptionPane.showMessageDialog(null, e);
        e.printStackTrace();
    }

Answer 1

抛出异常是因为查询中没有要填充的参数的占位符。您应该使用 ? 字符而不是硬编码值:

String query="select * from Users where Username =? and password=?  ";
PreparedStatement pst=connection.prepareStatement(query);
pst.setString(1, text_username.getText());
pst.setString(2, passwordField.getText());