我已经为我的Java GUI程序创建了一个登录界面。在点击按钮时，该登录界面会检查文本框中输入的用户名和密码是否与文本文件中的行相等，如果相等，则允许用户进入下一个界面。否则，将显示一个
我的问题是它只读取最后两行代码，所以我只能使用最后创建的用户名和密码登录。如何才能使其读取每一行以检查用户名和密码？ 主要登录界面
JOptionPane.showMessageDialog 。我还有另一个屏幕，允许用户写入文件并插入新的用户名和密码。我的问题是它只读取最后两行代码，所以我只能使用最后创建的用户名和密码登录。如何才能使其读取每一行以检查用户名和密码？ 主要登录界面
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
public class login extends JFrame {
JButton blogin;
JPanel loginpanel;
JTextField txuser;
JTextField pass;
JButton newUSer;
JLabel username;
JLabel password;
public login(){
super("Login Autentification");
blogin = new JButton("Login");
loginpanel = new JPanel();
txuser = new JTextField(15);
pass = new JPasswordField(15);
newUSer = new JButton("New User?");
username = new JLabel("User - ");
password = new JLabel("Pass - ");
setSize(300,200);
setLocation(500,280);
loginpanel.setLayout (null);
txuser.setBounds(70,30,150,20);
pass.setBounds(70,65,150,20);
blogin.setBounds(110,100,80,20);
newUSer.setBounds(110,135,80,20);
username.setBounds(20,28,80,20);
password.setBounds(20,63,80,20);
loginpanel.add(blogin);
loginpanel.add(txuser);
loginpanel.add(pass);
loginpanel.add(newUSer);
loginpanel.add(username);
loginpanel.add(password);
getContentPane().add(loginpanel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
Writer writer = null;
File check = new File("userPass.txt");
if(check.exists()){
//Checks if the file exists. will not add anything if the file does exist.
}else{
try{
File texting = new File("userPass.txt");
writer = new BufferedWriter(new FileWriter(texting));
writer.write("message");
}catch(IOException e){
e.printStackTrace();
}
}
blogin.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
File file = new File("userPass.txt");
Scanner scan = new Scanner(file);;
String line = null;
FileWriter filewrite = new FileWriter(file, true);
String usertxt = " ";
String passtxt = " ";
String puname = txuser.getText();
String ppaswd = pass.getText();
while (scan.hasNext()) {
usertxt = scan.nextLine();
passtxt = scan.nextLine();
}
if(puname.equals(usertxt) && ppaswd.equals(passtxt)) {
MainMenu menu =new MainMenu();
dispose();
}
else if(puname.equals("") && ppaswd.equals("")){
JOptionPane.showMessageDialog(null,"Please insert Username and Password");
}
else {
JOptionPane.showMessageDialog(null,"Wrong Username / Password");
txuser.setText("");
pass.setText("");
txuser.requestFocus();
}
} catch (IOException d) {
d.printStackTrace();
}
}
});
newUSer.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
NewUser user = new NewUser();
dispose();
}
});
}
}
新用户文件
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
public class NewUser extends JFrame {
JButton create;
JPanel newUserPanel;
JTextField txuserer;
JTextField passer;
public NewUser(){
super("Registration");
create = new JButton("Create");
newUserPanel = new JPanel();
txuserer = new JTextField(15);
passer = new JPasswordField(15);
setSize(300,200);
setLocation(500,280);
newUserPanel.setLayout (null);
txuserer.setBounds(70,30,150,20);
passer.setBounds(70,65,150,20);
create.setBounds(110,100,80,20);
newUserPanel.add(create);
newUserPanel.add(txuserer);
newUserPanel.add(passer);
getContentPane().add(newUserPanel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
Writer writer = null;
File check = new File("userPass.txt");
if(check.exists()){
//Checks if the file exists. will not add anything if the file does exist.
}else{
try{
File texting = new File("userPass.txt");
writer = new BufferedWriter(new FileWriter(texting));
writer.write("message");
}catch(IOException e){
e.printStackTrace();
}
}
create.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
File file = new File("userPass.txt");
Scanner scan = new Scanner(file);;
FileWriter filewrite = new FileWriter(file, true);
String usertxter = " ";
String passtxter = " ";
String punamer = txuserer.getText();
String ppaswder = passer.getText();
while (scan.hasNext()) {
usertxter = scan.nextLine();
passtxter = scan.nextLine();
}
if(punamer.equals(usertxter) && ppaswder.equals(passtxter)) {
JOptionPane.showMessageDialog(null,"Username is already in use");
txuserer.setText("");
passer.setText("");
txuserer.requestFocus();
}
else if(punamer.equals("") && ppaswder.equals("")){
JOptionPane.showMessageDialog(null,"Please insert Username and Password");
}
else {
filewrite.write(punamer+"\r\n" +ppaswder+ "\r\n");
filewrite.close();
JOptionPane.showMessageDialog(null,"Account has been created.");
dispose();
login log = new login();
}
} catch (IOException d) {
d.printStackTrace();
}
}
});
}
}
.setLayout(null);和.setBounds(20,28,80,20);-- 你不想这样做。认真点。 - Hovercraft Full Of Eelsnull布局，像素完美布局在现代用户界面设计中是一种幻觉。有太多的因素影响组件的大小，而这些因素都是不可控制的。Swing被设计为与布局管理器一起工作，抛弃它们会导致无尽的问题和困难，最终你会花费更多的时间来解决。 - MadProgrammer