Question

我正在尝试以类似

的形式添加有效性控制

不允许空字段
电子邮件地址必须采用格式名称@ domain
日期必须采用dd.mm.yyyy
比较密码

此外，在这些检查之后，我无法弄清楚如何停止进一步处理表单，并让用户在接受表单提交之前再次输入缺失或错误的数据。

这是我的代码：

package examsuite;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;

public class SignUp extends JFrame implements ActionListener
{
JLabel jlb,jlfna,jllna,jldob,jlqu,jlph,jlpw,jlpc,jlem;
JTextField jtfna,jtlna,jtdob,jtqu,jtph,jtem;
JPasswordField jtpw, jtpc;
JButton jbsav,jblog;
Container c;
Connection conn;
PreparedStatement pstmt;

SignUp()
{
try
{
        Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
        conn=DriverManager.getConnection("jdbc:odbc:ExamSuite","","");
}
    catch(ClassNotFoundException e)
{
        System.out.println("class not exception");
}
    catch(SQLException e)
{
        System.out.println("sql exception");
}     

        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

public void setUp()
{
        c=getContentPane();
        setSize(900,750);
        setTitle("Exam Suite");
        c.setBackground(Color.white);
        c.setLayout(null);

        jlb=new JLabel(new ImageIcon("uit.jpg"));
        jlb.setBounds(0,0,900,120);

        jlfna=new JLabel("First Name");
        jlfna.setBounds(260,170,120,30);

        jtfna=new JTextField();
        jtfna.setBounds(440,170,120,30);

        jllna=new JLabel("Last Name");
        jllna.setBounds(260,230,120,30);

        jtlna=new JTextField();
        jtlna.setBounds(440,230,120,30);

        jldob=new JLabel("Date of Birth");
        jldob.setBounds(260,290,120,30);

        jtdob=new JTextField();
        jtdob.setBounds(440,290,120,30);

        jlqu=new JLabel("Qualification");
        jlqu.setBounds(260,350,120,30);

        jtqu=new JTextField();
        jtqu.setBounds(440,350,120,30);

        jlph=new JLabel("Phone No.");
        jlph.setBounds(260,410,120,30);

        jtph=new JTextField();
        jtph.setBounds(440,410,120,30);

        jlem=new JLabel("E mail");
        jlem.setBounds(260,470,120,30);

        jtem=new JTextField();
        jtem.setBounds(440,470,120,30);

        jlpw=new JLabel("Password");
        jlpw.setBounds(260,530,120,30);

        jtpw=new JPasswordField();
        jtpw.setBounds(440,530,120,30);

        jlpc=new JLabel("Confirm Password");
        jlpc.setBounds(260,590,120,30);

        jtpc=new JPasswordField();
        jtpc.setBounds(440,590,120,30);

        jbsav=new JButton("Save");  
        jbsav.setBounds(260,650,100,30);

        jblog=new JButton("Go to Login");   
        jblog.setBounds(460,650,100,30);

        c.add(jlb);
        c.add(jlfna);
        c.add(jtfna);
        c.add(jllna);
        c.add(jtlna);   
        c.add(jldob);
        c.add(jtdob);
        c.add(jlqu);
        c.add(jtqu);
        c.add(jlph);
        c.add(jtph);
        c.add(jlem);
        c.add(jtem);
        c.add(jlpw);
        c.add(jtpw);
        c.add(jlpc);
        c.add(jtpc);

        c.add(jbsav);
        c.add(jblog);

        jbsav.addActionListener(this);
        jblog.addActionListener(this);

        setVisible(true);
}

public void actionPerformed(ActionEvent ae)
{
    String s=ae.getActionCommand();
    Object obj=ae.getSource();
    String email=new String(" ");
    if(s.equals("Save"))
    {

                if(jtfna.getText().equals("") | jtlna.getText().equals("") | jtdob.getText().equals("")
                   | jtqu.getText().equals("") | jtph.getText().equals("") | jtem.getText().equals("")
                   | jtpw.getText().equals("") | jtpc.getText().equals(""))
                {
                    JOptionPane.showMessageDialog(this, "Error entering data - All fields must be filled.", "Exam Suite - Data Entry Error", JOptionPane.PLAIN_MESSAGE);
                }
                else if(!(jtpw.getText().equals(jtpc)))
                {
                    JOptionPane.showMessageDialog(this, "Error entering password - Passwords do not match.", "Exam Suite - Password Entry Error", JOptionPane.PLAIN_MESSAGE);
                }

        try
        {
            pstmt=conn.prepareStatement("insert into registration values(?,?,?,?,?,?,?)");

            String fname=jtfna.getText();
            pstmt.setString(2,fname);
            String lname=jtlna.getText();
            pstmt.setString(3,lname);
            String dob=jtdob.getText();
            pstmt.setString(4,dob);
            String qual=jtqu.getText();
            pstmt.setString(5,qual);
            String ph=jtph.getText();
            pstmt.setString(6,ph);
            email=jtem.getText();
            pstmt.setString(1,email);
            String pw=jtpw.getText();
            pstmt.setString(7,pw);

            pstmt.executeUpdate();
        }
        catch(SQLException se)
        {
            JOptionPane.showMessageDialog (this, "Error in saving the file", "Exam Suite - SQL Error", JOptionPane.PLAIN_MESSAGE);
        }

        JOptionPane.showMessageDialog (this, "Successful Registration ", "Exam Suite ", JOptionPane.PLAIN_MESSAGE);
        jtfna.setText("");
        jtlna.setText("");
        jtdob.setText("");
        jtqu.setText("");
        jtph.setText("");
        jtem.setText("");
        jtpw.setText(""); 
    }

    if(s.equals("Go to Login"))
    {
        new LogFom().setup();
        setVisible(false);
    }       
}   

//public static void main(String args[])
//{
//  SignUp rt=new SignUp();
//  rt.setUp();
//}

}

Answer 1

此外，经过这些检查后，我无法弄清楚如何进一步停止处理表格......

if(jtfna.getText().equals("") | jtlna.getText().equals("") | jtdob.getText().equals("")
                   | jtqu.getText().equals("") | jtph.getText().equals("") | jtem.getText().equals("")
                   | jtpw.getText().equals("") | jtpc.getText().equals(""))
                {
                    JOptionPane.showMessageDialog(this, "Error entering data - All fields must be filled.", "Exam Suite - Data Entry Error", JOptionPane.PLAIN_MESSAGE);
                    //RETURN WITHOUT GOING AHEAD 
                    return;
                }
                else if(!(jtpw.getText().equals(jtpc)))
                {
                    JOptionPane.showMessageDialog(this, "Error entering password - Passwords do not match.", "Exam Suite - Password Entry Error", JOptionPane.PLAIN_MESSAGE);
                  //RETURN WITHOUT GOING AHEAD 
                  return;
                }

然而，最好使用for循环遍历用户界面的每个组件，当您找到必须填充的组件时，显示一个optionpane，同时还包含用户必须填充的控件的名称，或者更好地更改背景必须由用户填写的组件的颜色（例如红色）......

Java中的有效性控制和密码比较

1 个答案: