[英]Copying text from a textfield from one class to another. (Java)
因此，我想在另一個班級的一個班級中使用文本框中的文本，但是我無法傳遞它。 我或多或少希望在SQL查詢中使用它，以便可以從其他表中獲得相同的用戶信息。 這是我的登錄課程的第一部分。 第二個是TaskViewer類。 我需要登錄中textFieldUN中的內容才能轉到TaskViewer，以便每次特定的用戶登錄時都可以訪問正確的用戶信息。謝謝您的幫助！ 如果不清楚，請告訴我，我會盡力解釋。 抱歉，第一次使用此網站！
public class Login {
private JFrame frame;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Login window = new Login();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
Connection connection = null;
private JTextField textFieldUN;
private JPasswordField passwordField;
/**
* Create the application.
*/
public Login() {
initialize();
connection = sqliteConnection.dbConnector();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 667, 399);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JLabel lblNewLabel = new JLabel("Username:");
lblNewLabel.setBounds(234, 95, 75, 27);
frame.getContentPane().add(lblNewLabel);
JLabel lblNewLabel_1 = new JLabel("Password:");
lblNewLabel_1.setBounds(234, 162, 75, 27);
frame.getContentPane().add(lblNewLabel_1);
textFieldUN = new JTextField();
textFieldUN.setBounds(321, 95, 232, 39);
frame.getContentPane().add(textFieldUN);
textFieldUN.setColumns(10);
JButton btnNewButton = new JButton("Login");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
try {
String query = "SELECT * FROM User_Info WHERE Username = ? and Password = ?"; //index 1 for UN 2 for PW
PreparedStatement pst = connection.prepareStatement(query); //Must pass query
pst.setString(1, textFieldUN.getText() ); //UN get
pst.setString(2, passwordField.getText() ); //PW get //it is crossed put because of the password masking
ResultSet rs = pst.executeQuery();
//String userNameEntered = textFieldUN.getText();
int count = 0;
while(rs.next()) {
count = count +1;
}
if (count == 1)
{
JOptionPane.showMessageDialog(null, "User name and password is correct!");
frame.dispose();
TaskViewer tskvwr = new TaskViewer();
tskvwr.setVisible(true);
}
else if(count > 1)
{
JOptionPane.showMessageDialog(null, "Duplicated user name and password!");
}
else
{
JOptionPane.showMessageDialog(null, "User name or password is incorrect!");
}
rs.close();
pst.close();
}catch(Exception e)
{
JOptionPane.showMessageDialog(null, e);
}
}
});
btnNewButton.setBounds(415, 244, 138, 39);
frame.getContentPane().add(btnNewButton);
passwordField = new JPasswordField();
passwordField.setBounds(321, 156, 232, 39);
frame.getContentPane().add(passwordField);
}
}
public class TaskViewer extends JFrame {
private JPanel contentPane;
private JTable table;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
TaskViewer frame = new TaskViewer();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
Connection connection = null;
public TaskViewer() {
connection = sqliteConnection.dbConnector(); //need to connect to db
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 602, 402);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JButton btnLoadTable = new JButton("Load Task");
btnLoadTable.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
try {
//String usernameretrieved = .UsernameRetriever()
String query = "SELECT * FROM Task WHERE Username = ?";//I need to only get the task from a singular user from login
// WHERE I WANT TO USE THE TEXT BOX TO QUERY, I KNOW ? IS WRONG
PreparedStatement pst = connection.prepareStatement(query);
pst.setString(1, textFieldUN.getText() );
ResultSet rs = pst.executeQuery();
table.setModel(DbUtils.resultSetToTableModel(rs)); //DbUtil is from rs2
} catch (Exception e) {
e.printStackTrace();
}
}
});
btnLoadTable.setBounds(34, 41, 97, 25);
contentPane.add(btnLoadTable);
JScrollPane scrollPane = new JScrollPane();
scrollPane.setBounds(177, 41, 376, 248);
contentPane.add(scrollPane);
table = new JTable();
scrollPane.setViewportView(table);
}
}
public class sqliteConnection {
Connection conn = null;
public static Connection dbConnector()
{
try {
Class.forName("org.sqlite.JDBC");
Connection conn = DriverManager.getConnection("jdbc:sqlite:C:\\Users\\a pathway
//JOptionPane.showMessageDialog(null, "Connection is up and running!");
return conn;
}catch(Exception e)
{
JOptionPane.showMessageDialog(null, e);
return null;
}
}
}
這是一個非常簡單的應用程序。 在這里，我使用JDialog來顯示我的登錄面板，並保持對程序的控制，直到用戶成功登錄為止。
public class LoginPanel extends JPanel {
private String userName = null;
private JDialog dialog;
public LoginPanel(JDialog d) {
dialog = d;
// call initialize method to build your GUI here
// don't forget to attach the ActionListener methods to the correct buttons
}
private void closeWindow() {
dialog.dispose();
}
public String getUserName() {
return userName;
}
private void okButtonActionPerformed(java.awt.event.ActionEvent evt) {
String userInput = userNameTextField.getText();
// validate user input here
// if it's good, set username variable and call closeWindow
userName = userInput;
closeWindow();
}
private void cancelButtonActionPerformed(java.awt.event.ActionEvent evt) {
userName = null;
closeWindow();
}
}
然后這是您的主應用程序JFrame與主類
public class TaskViewer extends JFrame {
private static String userName = null;
public TaskViewer() {
// call initialize method that builds your GUI here
// don't forget to attach the formWindowOpened WindowListener to your JFrame
}
private void formWindowOpened(java.awt.event.WindowEvent evt) {
initLogin();
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new TaskViewer().setVisible(true);
}
});
}
public void initLogin() {
JDialog dialog = new JDialog(this, "Login",
Dialog.ModalityType.APPLICATION_MODAL); /* this modality setting will keep
focus on the dialog until the OK
or Cancel button is clicked */
LoginPanel login = new LoginPanel(dialog);
dialog.add(login);
dialog.pack();
dialog.setLocationRelativeTo(this);
dialog.setVisible(true);// this passes control to your dialog window
// program will resume here once the dialog is destroyed
userName = login.getUserName();
if(userName == null) {
// do error checking here
} else {
// you're good, let's use the program!
}
}
}
關於安全性的附帶說明：您永遠不要向用戶報告錯誤消息，即他們輸入的用戶名和密碼是重復的，因為您只是告訴他們另一個用戶的名稱和密碼...
我知道您找到了解決方案，但我想也許您會發現這很有用。 在我看來，您只需要一種登錄名（用戶名和密碼）輸入機制，一旦掌握了該信息，就可以進行相應的處理。 對於這種情況（我認為），處理登錄方案的最簡單方法是利用自定義模式對話框。 在應用程序可見之前，必須先滿足登錄名，然后才能滿足您和您的代碼的要求。 您所需要做的就是讓用戶提供名稱和密碼，以便在您的應用程序出現之前進行驗證。 通常，無論如何，這始終是這樣的：
這是可運行的代碼，其中包含生成和顯示上述“登錄對話框”窗口的方法。 該代碼是您自己的TaskView類，對其進行了一些修改並添加了方法。 此處已完全消除了Login類，但您的sqliteConnection類保持不變，只是將其重命名為SQLiteConnection ：
/*
In this modified example, the Database connection is opened
and closed before and after every DB access operation. I don't
think Connection Pooling is required here....yet.
The image used in the Login Dialog can be downloaded from here:
https://www.freeiconspng.com/img/3059
*/
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;
import javax.swing.table.DefaultTableModel;
public class TaskViewer extends JFrame {
// Class global member variables
private String applicationUserName; // Will hold the logged in User Name.
private String applicationUserPassword; // Will hold the Logged in User Password.
// Constructor
public TaskViewer() {
// Keep it tidy and simple.
initializeTaskViewer();
}
/**
* Launch the application.
* @param args
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
new TaskViewer().startApp(); // Don't need static methods this way.
}
catch (Exception e) {
e.printStackTrace();
}
}
});
}
private void startApp() {
/*
View the TaskView application window. The Event Dispatch
Thread (EDT) doesn't actually let this happen until this
method is finished so, all you will see is the Login Dialog
when the application starts and validation is satisfied.
Since we extend JFrame in this Class, we don't have to
instantiate as new TaskView. Doing so will just wipe out the
class member variables we had set with our Login Dialog
since it would now be a new instance of TaskView.
*/
setVisible(true);
String message = "<html>Please supply your Login information. If "
+ "you are<br>a New User then you will be automatically added<br>"
+ "to the database.<br><br><br>";
String title = "TaskView - User Login ...";
String userNameCaption = null; //"User Name:";
String passwordCaption = null; //"Password:";
String footNoteCaption = "<html><pre><font size=2> "
+ "Select <font color=red>Cancel</font> to quit</font></pre><br></html>";
Color backColor = Color.decode("#ffe6cc"); // our custom background color.
//Object dialogImage = JOptionPane.QUESTION_MESSAGE; // You can do it this way...
// or this way...
Object dialogImage = "login-icon-3059.png|80,80"; // get image from: https://www.freeiconspng.com/img/3059
// The text captions for our dialog buttons
Object[] buttonCaptions = {"<html><font color=red>Login</font> To TaskView</html>",
"<html><font color=red>Cancel</font> - Quit</html>"};
// The call to our Custom Login Dialog
String[] loginPass = customLoginInputBox(null, message, title, userNameCaption, passwordCaption,
footNoteCaption, backColor, dialogImage, buttonCaptions);
/* The call could very well look like this...
String[] loginPass = customLoginInputBox(null, message, title, null, null, null, null, null, null);
...but the dialog looks pretty bland ;p */
if (loginPass[0] == null) {
JOptionPane.showMessageDialog(this, "Login Not Supplied! Quiting...",
"Invalid Login", JOptionPane.WARNING_MESSAGE);
System.exit(0);
}
else {
applicationUserName = loginPass[0];
applicationUserPassword = loginPass[1];
}
boolean valid = validateLogin(applicationUserName, applicationUserPassword);
if (!valid) {
System.exit(0);
}
}
private void initializeTaskViewer() {
setTitle("TaskView v1.0.0");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 602, 402);
JPanel contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JTable table = new JTable();
JButton btnLoadTable = new JButton("Load Tasks");
btnLoadTable.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent arg0) {
Connection connection = null;
try {
connection = SQLiteConnection.dbConnector();
String query = "SELECT * FROM Task WHERE Username = ?";
PreparedStatement pst = connection.prepareStatement(query);
pst.setString(1, applicationUserName);
ResultSet rs = pst.executeQuery();
// Don't need dependency on DbUtil with this provided small method.
resultSetToJTable(table, rs);
//table.setModel(DbUtils.resultSetToTableModel(rs)); //DbUtil is from rs2
}
catch (Exception e) {
Logger.getLogger(TaskViewer.class.getName()).log(Level.SEVERE, null, e);
}
finally {
try {
// Closeing the connection will automatically
// close pst and rs.
if (connection != null) { connection.close(); }
}
catch (SQLException ex) {
Logger.getLogger(TaskViewer.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
});
btnLoadTable.setBounds(34, 41, 100, 25);
contentPane.add(btnLoadTable);
JScrollPane scrollPane = new JScrollPane(table);
scrollPane.setBounds(177, 41, 376, 248);
contentPane.add(scrollPane);
// Set Appplication window in center of screen.
// Must be done just before setVisible() is used.
setLocationRelativeTo(null);
}
/**
* Displays a modal Custom Input Dialog Box where a User Name and Password
* can be supplied.
*
* @param component (Component) The parent component from where
* the dialog will be displayed from. Null can
* be supplied if there is no apparent parent
* component. If null is supplied then a parent
* is temporarily created to ensure visibility
* and then disposed of when done.<br>
*
* @param message (String) The message body to display within
* the Login Dialog. The length of the message
* strings (before and after line breaks) can
* determine how large the dialog will become.
* The use of line breaks can be pertinent
* here. HTML can be used to create your
* message.<br>
*
* @param title (String) The title to be displayed within
* the Login Dialog window title bar. Only
* plain text can be used here.<br>
*
* @param userNameBoxCaption (String) The User Name entry text box
* contains a text caption to the left of it so
* as to indicate what the entry box is for. By
* default this caption states: "User Name:".
* If you want to change this default caption
* then you can supply it here. If you prefer
* to use the default then simply supply null.
* HTML can be used here.<br>
*
* @param passwordBoxCaption (String) The Password entry text box
* contains a text caption to the left of it so
* as to indicate what the entry box is for. By
* default this caption states: "Password:". If
* you want to change this default caption then
* you can supply it here. If you prefer to use
* the default then simply supply null. HTML
* can be used here.<br>
*
* @param dialogFootNoteCaption (string) By default there is no footer
* caption. The footer text caption is
* displayed below and between the Password
* entry box and the dialog buttons located at
* the bottom of the dialog. Any additional
* information can be supplied here if desired.
* HTML can be used here as well.<br>
*
* @param dialogBackColor (Color) You can set the desired background
* color for your Login Dialog. By default is
* would be the default Message Box color for
* your specific Operating System or to
* whatever Look & Feel currently being used by
* your application. Any color can be supplied
* as long as it is supplied as a Color
* Object.<br>
*
* @param dialogImage (Object) This parameter is a little special.
* By default a standard JOptionPane Question
* Message icon is displayed to the left side
* of the Login Dialog. If you want to change
* this icon to any one of the other
* JOptionPane Icons then you can simply supply
* any one of them here in the form of:<pre>
*
* JOptionPane.ERROR_MESSAGE;
* JOptionPane.INFORMATION_MESSAGE
* JOptionPane.PLAIN_MESSAGE
* JOptionPane.QUESTION_MESSAGE
* JOptionPane.WARNING_MESSAGE</pre><br>
*
* If however you want to utilize your own custom image (transparent
* background .png is best) then you can supply the path and file name of
* your image to this parameter as string. You can also optionally preset a
* specific size for your image by placing a Pipe (|) delimiter at the end
* of the path string and supplying integer values for width and height, for
* example:
* <pre>
*
* "C:\\My App Path\\Images\\logo.png|80,80"</pre><br>
*
* In the example image path string above we're telling the method to resize
* the image to 80 pixels wide by 80 pixels high. The delimiter used to
* separate the Width and Height in the above path string is a comma (,) but
* can very well be a whitespace, a semicolon (;), or a colon (:). Any one
* of the four will work as a Width/Height delimiter.<br><br>
*
* This parameter will accept either a integer value or a string value. If a
* integer value is supplied then it will be assumed that a JOptionPane icon
* is supplied. If a string value is supplied then it will be assumed that
* it is the path to a custom image file located within the local file
* system.<br>
*
* @param dialogButtonCaptions (Single Dimensional (1D) Object[] Array)
* There are only two buttons within the Login
* Dialog and by default they are the "OK" and
* "Cancel" buttons (cancel has default focus).
* Both by default contain the aforementioned
* respective text captions. If you want to
* change these button captions then you can do
* so here by supplying a object array of
* button caption strings, for example:<pre>
*
* Object[] buttonCaptions = {"Login To App", "Cancel/Quit"};</pre><br>
*
* HTML can be used in the caption strings.<br>
*
* @return (Single Dimensional (1D) String[] Array) The returned string
* array will only ever contain two specific elements, the supplied
* Login Name and the supplied Password. If null in either or both
* elements is returned then the dialog was canceled (right-most
* button selected) or the dialog was closed with the dialog window
* close [x] button. The dialog can not be closed unless proper
* credentials (name and password) are supplied or the dialog is
* canceled.
*/
public String[] customLoginInputBox(Component component, String message, String title,
String userNameBoxCaption, String passwordBoxCaption,
String dialogFootNoteCaption, Color dialogBackColor,
Object dialogImage, Object[] dialogButtonCaptions) {
String[] result = {null, null};
Object[] buttonCaptions = {"OK", "Cancel"};
if (dialogButtonCaptions != null && dialogButtonCaptions.length > 0) {
buttonCaptions = Arrays.copyOf(dialogButtonCaptions, dialogButtonCaptions.length);
}
Component comp = component;
JFrame iFRAME = new JFrame();
if (comp == null) {
/* Create a dummy JFrame. This is done so that
the Dialog box that is used in the application
does not hide behind the IDE or ON TOP form if
null is used for the parent component. Not a
problem for some.
*/
iFRAME.setAlwaysOnTop(true);
comp = iFRAME;
}
String userNameCaption = "User Name: "; // Default caption
if (userNameBoxCaption != null && !userNameBoxCaption.equals("")) {
userNameCaption = userNameBoxCaption;
}
String passwordCaption = "Password: "; // Default caption
if (passwordBoxCaption != null && !passwordBoxCaption.equals("")) {
passwordCaption = passwordBoxCaption;
}
// Default dialog footnote (no footnote).
String footNote = dialogFootNoteCaption == null
|| dialogFootNoteCaption.equals("") ? " " : dialogFootNoteCaption;
String uName = "";
String passWrd = "";
// Set dialog background to white.
Color origPanelColor = (Color) UIManager.get("OptionPane.background");
Color origPaneBackgroundColor = (Color) UIManager.get("Panel.background");
if (dialogBackColor != null) {
try {
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
UIManager.put("OptionPane.background", dialogBackColor);
UIManager.put("Panel.background", dialogBackColor);
}
catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
Logger.getLogger("customLoginInputBox() Method Error!").log(Level.SEVERE, null, ex);
}
}
// Get User input as to User Name and Password.
// using a custom Input Dialog...
// Build the Login dialog Panel...
BorderLayout layout = new BorderLayout();
JPanel panel = new JPanel(layout);
panel.setBackground(dialogBackColor);
JLabel label = new JLabel(message);
panel.add(label, BorderLayout.NORTH);
JPanel p = new JPanel(new BorderLayout(5, 5));
p.setBackground(dialogBackColor);
JPanel labels = new JPanel(new GridLayout(0, 1, 2, 2));
labels.setBackground(dialogBackColor);
labels.add(new JLabel(userNameCaption, SwingConstants.RIGHT));
labels.add(new JLabel(passwordCaption, SwingConstants.RIGHT));
p.add(labels, BorderLayout.WEST);
JPanel controls = new JPanel(new GridLayout(0, 1, 2, 2));
controls.setBackground(dialogBackColor);
JTextField userName = new JTextField();
controls.add(userName);
JPasswordField password = new JPasswordField();
controls.add(password);
p.add(controls, BorderLayout.CENTER);
panel.add(p);
JLabel baseLabel = new JLabel(footNote);
panel.add(baseLabel, BorderLayout.SOUTH);
// The custom Image to use in Login dialog...
ImageIcon icon = null;
int msgType = JOptionPane.QUESTION_MESSAGE;
if (dialogImage != null && dialogImage.getClass().getSimpleName().toUpperCase().equals("STRING")) {
String dString = dialogImage.toString();
int sizeWidth = 0, sizeHeight = 0;
if (dString.contains("|")) {
String[] dsTmp = dString.split("\\|");
dString = dsTmp[0];
if (dsTmp[1].contains(",") || dsTmp[1].contains(";")
|| dsTmp[1].contains(":") || dsTmp[1].contains(" ")) {
try {
sizeWidth = Integer.parseInt(dsTmp[1].split(",|;|:|\\s+")[0]);
sizeHeight = Integer.parseInt(dsTmp[1].split(",|;|:|\\s+")[1]);
}
catch (Exception e) {
}
}
}
icon = new ImageIcon(dString);
if (sizeWidth == 0) {
sizeWidth = icon.getIconWidth();
}
if (sizeHeight == 0) {
sizeHeight = icon.getIconHeight();
}
Image image = icon.getImage();
// Size it to what you want (this example uses: 128 x 128).
Image newimg = image.getScaledInstance(sizeWidth, sizeHeight, java.awt.Image.SCALE_SMOOTH);
icon = new ImageIcon(newimg);
}
else if (dialogImage != null && dialogImage.getClass().getSimpleName().toUpperCase().equals("INTEGER")) {
msgType = (int) dialogImage;
}
// Get Input from User. This will display
// your custom Input Dialog Box.
while (uName.equals("") || passWrd.equals("")) {
int res = JOptionPane.showOptionDialog(iFRAME, panel, title,
JOptionPane.OK_CANCEL_OPTION, msgType, icon, buttonCaptions, buttonCaptions[1]);
// Process the result from our custom Input Dialog Box
if (res == JOptionPane.OK_OPTION && !userName.getText().equals("")
&& !Arrays.toString(password.getPassword()).equals("")) {
uName = userName.getText();
char[] pass = password.getPassword();
for (int i = 0; i < pass.length; i++) {
passWrd += Character.toString(pass[i]);
}
if (uName.equals("") || passWrd.equals("")) {
Toolkit.getDefaultToolkit().beep();
continue;
}
// Do whatever you want with User Name and Password
result[0] = uName;
result[1] = passWrd;
}
else {
if (res == 1 || res == -1) {
break;
}
}
}
iFRAME.dispose(); // Dispose of the temp parent for the dialog.
// Set UI Colors back to original.
if (dialogBackColor != null) {
try {
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
UIManager.put("OptionPane.background", origPanelColor);
UIManager.put("Panel.background", origPaneBackgroundColor);
}
catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
Logger.getLogger("customLoginInputBox() Method Error!").log(Level.SEVERE, null, ex);
}
}
return result;
}
private boolean validateLogin(String userName, String userPassword) {
boolean isValid = false;
Connection connection = SQLiteConnection.dbConnector();
try {
String query = "SELECT * FROM User_Info WHERE Username = ? and Password = ?";
try (PreparedStatement pst = connection.prepareStatement(query)) {
pst.setString(1, userName);
pst.setString(2, userPassword);
try (ResultSet rs = pst.executeQuery()) {
int count = 0;
while (rs.next()) {
if (rs.getString("Username").equals(userName) &&
rs.getString("Password").equals(userPassword)) {
isValid = true;
break; // don't need loop any more
}
}
}
if (isValid) {
JOptionPane.showMessageDialog(this, "User name and password is correct!",
"Login Valid", JOptionPane.INFORMATION_MESSAGE);
}
else {
JOptionPane.showMessageDialog(this, "User name or password is incorrect!",
"Login Invalid!", JOptionPane.ERROR_MESSAGE);
// You may want to add a mechanism to add new User to database here.
}
}
}
catch (Exception e) {
JOptionPane.showMessageDialog(null, e);
}
finally {
try {
if (connection != null) { connection.close(); }
}
catch (SQLException ex) {
Logger.getLogger(TaskViewer.class.getName()).log(Level.SEVERE, null, ex);
}
}
return isValid;
}
/**
* Fills the supplied JTable with the Column Names and Data from a supplied
* ResultSet.<br><br>
*
* @param table (JTable) The variable name of the JTable to fill.<br>
*
* @param rs (ResultSet) The ResultSet to fill JTable from.
*/
public void resultSetToJTable(JTable table, ResultSet rs) {
try {
DefaultTableModel tableModel = new DefaultTableModel();
ResultSetMetaData metaData = rs.getMetaData();
int columnCount = metaData.getColumnCount();
for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
tableModel.addColumn(metaData.getColumnLabel(columnIndex));
}
Object[] row = new Object[columnCount];
while (rs.next()) {
for (int i = 0; i < columnCount; i++) {
row[i] = rs.getObject(i + 1);
}
tableModel.addRow(row);
}
table.setModel(tableModel);
}
catch (SQLException ex) {
System.err.println("resultSetToJTable() Method Error! - "
+ System.lineSeparator() + ex.getMessage());
}
}
}
將上面的代碼復制並粘貼到新項目中 ，並添加具有適當數據庫信息的SQLiteConnection類，然后運行該應用程序以查看其工作方式。 別忘了還將SQLite JDBC驅動程序庫添加到這個新項目中。
請注意，盡管此處已做過，但永遠不要以純文本格式存儲密碼，而應存儲該密碼的哈希值。 除了用戶外，沒有人應該知道他或她的密碼是什么。 它應該是將提供的密碼的哈希值（帶有鹽）與存儲在數據庫表中的哈希值進行比較。 甚至您都不應該知道密碼。 研究使用BCrypt或jBCrypt 。 鏈接中的小代碼段顯示了它的易用性。 而且，您已經知道要通知用戶輸入的名稱和密碼已被使用，這簡直是白費力氣。
在另一個Java類中使用變量/數組。 合並簡單的Java文件？
[英]Use a variable/array from one java class, in another. Combine simple java files?
從一個類在另一個字符串上調用一個方法（hashmap / hashset）。
[英]Calling a method (hashmap/ hashset) from one class on a string in another.
Java Swing-如何從另一個類獲取TextField中的文本值
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