我的代码有问题。它（应该是）一个电子邮件客户端，可以选择读取消息并发送它们 - 问题是，它不下载消息而无法发送消息 - 我认为问题出在连接。
该计划包括以下课程
EmailClient：电子邮件客户端应用程序的主要类
ConnectDialog：此类显示用于输入电子邮件服务器连接设置的对话框
MessagesTableModel：此类管理电子邮件表的数据
MessageDialog：此类显示用于创建消息的对话框。
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.swing.*;
import javax.swing.event.*;
// The E-mail Client. public class EmailClient extends JFrame {
// Message table's data model.
private MessagesTableModel tableModel;
// Table listing messages.
private JTable table;
// This the text area for displaying messages.
private JTextArea messageTextArea;
/* This is the split panel that holds the messages
table and the message view panel. */
private JSplitPane splitPane;
// These are the buttons for managing the selected message.
private JButton replyButton, forwardButton, deleteButton;
// Currently selected message in table.
private Message selectedMessage;
// Flag for whether or not a message is being deleted.
private boolean deleting;
// This is the JavaMail session.
private Session session;
// Constructor for E-mail Client.
public EmailClient() {
// Set application title.
setTitle("E-mail Client");
// Set window size.
setSize(640, 480);
// Handle window closing events.
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
actionExit();
}
});
// Setup file menu.
JMenuBar menuBar = new JMenuBar();
JMenu fileMenu = new JMenu("File");
fileMenu.setMnemonic(KeyEvent.VK_F);
JMenuItem fileExitMenuItem = new JMenuItem("Exit",
KeyEvent.VK_X);
fileExitMenuItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionExit();
}
});
fileMenu.add(fileExitMenuItem);
menuBar.add(fileMenu);
setJMenuBar(menuBar);
// Setup buttons panel.
JPanel buttonPanel = new JPanel();
JButton newButton = new JButton("New Message");
newButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionNew();
}
});
buttonPanel.add(newButton);
// Setup messages table.
tableModel = new MessagesTableModel();
table = new JTable(tableModel);
table.getSelectionModel().addListSelectionListener(new
ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
tableSelectionChanged();
}
});
// Allow only one row at a time to be selected.
table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
// Setup E-mails panel.
JPanel emailsPanel = new JPanel();
emailsPanel.setBorder(
BorderFactory.createTitledBorder("E-mails"));
messageTextArea = new JTextArea();
messageTextArea.setEditable(false);
splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
new JScrollPane(table), new JScrollPane(messageTextArea));
emailsPanel.setLayout(new BorderLayout());
emailsPanel.add(splitPane, BorderLayout.CENTER);
// Setup buttons panel 2.
JPanel buttonPanel2 = new JPanel();
replyButton = new JButton("Reply");
replyButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionReply();
}
});
replyButton.setEnabled(false);
buttonPanel2.add(replyButton);
forwardButton = new JButton("Forward");
forwardButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionForward();
}
});
forwardButton.setEnabled(false);
buttonPanel2.add(forwardButton);
deleteButton = new JButton("Delete");
deleteButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionDelete();
}
});
deleteButton.setEnabled(false);
buttonPanel2.add(deleteButton);
// Add panels to display.
getContentPane().setLayout(new BorderLayout());
getContentPane().add(buttonPanel, BorderLayout.NORTH);
getContentPane().add(emailsPanel, BorderLayout.CENTER);
getContentPane().add(buttonPanel2, BorderLayout.SOUTH);
}
// Exit this program.
private void actionExit() {
System.exit(0);
}
// Create a new message.
private void actionNew() {
sendMessage(MessageDialog.NEW, null);
}
// Called when table row selection changes.
private void tableSelectionChanged() {
/* If not in the middle of deleting a message, set
the selected message and display it. */
if (!deleting) {
selectedMessage =
tableModel.getMessage(table.getSelectedRow());
showSelectedMessage();
updateButtons();
}
}
// Reply to a message.
private void actionReply() {
sendMessage(MessageDialog.REPLY, selectedMessage);
}
// Forward a message.
private void actionForward() {
sendMessage(MessageDialog.FORWARD, selectedMessage);
}
// Delete the selected message.
private void actionDelete() {
deleting = true;
try {
// Delete message from server.
selectedMessage.setFlag(Flags.Flag.DELETED, true);
Folder folder = selectedMessage.getFolder();
folder.close(true);
folder.open(Folder.READ_WRITE);
} catch (Exception e) {
showError("Unable to delete message.", false);
}
// Delete message from table.
tableModel.deleteMessage(table.getSelectedRow());
// Update GUI.
messageTextArea.setText("");
deleting = false;
selectedMessage = null;
updateButtons();
}
// Send the specified message.
private void sendMessage(int type, Message message) {
// Display message dialog to get message values.
MessageDialog dialog;
try {
dialog = new MessageDialog(this, type, message);
if (!dialog.display()) {
// Return if dialog was cancelled.
return;
}
} catch (Exception e) {
showError("Unable to send message.", false);
return;
}
try {
// Create a new message with values from dialog.
Message newMessage = new MimeMessage(session);
newMessage.setFrom(new InternetAddress(dialog.getFrom()));
newMessage.setRecipient(Message.RecipientType.TO,
new InternetAddress(dialog.getTo()));
newMessage.setSubject(dialog.getSubject());
newMessage.setSentDate(new Date());
newMessage.setText(dialog.getContent());
// Send new message.
Transport.send(newMessage);
} catch (Exception e) {
showError("Unable to send message.", false);
}
}
// Show the selected message in the content panel.
private void showSelectedMessage() {
// Show hour glass cursor while message is loaded.
setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
try {
messageTextArea.setText(
getMessageContent(selectedMessage));
messageTextArea.setCaretPosition(0);
} catch (Exception e) {
showError("Unabled to load message.", false);
} finally {
// Return to default cursor.
setCursor(Cursor.getDefaultCursor());
}
}
/* Update each button's state based off of whether or not
there is a message currently selected in the table. */
private void updateButtons() {
if (selectedMessage != null) {
replyButton.setEnabled(true);
forwardButton.setEnabled(true);
deleteButton.setEnabled(true);
} else {
replyButton.setEnabled(false);
forwardButton.setEnabled(false);
deleteButton.setEnabled(false);
}
}
// Show the application window on the screen.
public void show() {
super.show();
// Update the split panel to be divided 50/50.
splitPane.setDividerLocation(.5);
}
// Connect to e-mail server.
public void connect() {
// Display connect dialog.
ConnectDialog dialog = new ConnectDialog(this);
dialog.show();
// Build connection URL from connect dialog settings.
StringBuffer connectionUrl = new StringBuffer();
connectionUrl.append(dialog.getType() + "://");
connectionUrl.append(dialog.getUsername() + ":");
connectionUrl.append(dialog.getPassword() + "@");
connectionUrl.append(dialog.getServer() + "/");
/* Display dialog stating that messages are
currently being downloaded from server. */
final DownloadingDialog downloadingDialog =
new DownloadingDialog(this);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
downloadingDialog.show();
}
});
// Establish JavaMail session and connect to server.
Store store = null;
try {
// Initialize JavaMail session with SMTP server.
Properties props = new Properties();
props.put("mail.smtp.host", dialog.getSmtpServer());
session = Session.getDefaultInstance(props, null);
// Connect to e-mail server.
URLName urln = new URLName(connectionUrl.toString());
store = session.getStore(urln);
store.connect();
} catch (Exception e) {
// Close the downloading dialog.
downloadingDialog.dispose();
// Show error dialog.
showError("Unable to connect.", true);
}
// Download message headers from server.
try {
// Open main "INBOX" folder.
Folder folder = store.getFolder("INBOX");
folder.open(Folder.READ_WRITE);
// Get folder's list of messages.
Message[] messages = folder.getMessages();
// Retrieve message headers for each message in folder.
FetchProfile profile = new FetchProfile();
profile.add(FetchProfile.Item.ENVELOPE);
folder.fetch(messages, profile);
// Put messages in table.
tableModel.setMessages(messages);
} catch (Exception e) {
// Close the downloading dialog.
downloadingDialog.dispose();
// Show error dialog.
showError("Unable to download messages.", true);
}
// Close the downloading dialog.
downloadingDialog.dispose();
}
// Show error dialog and exit afterwards if necessary.
private void showError(String message, boolean exit) {
JOptionPane.showMessageDialog(this, message, "Error",
JOptionPane.ERROR_MESSAGE);
if (exit)
System.exit(0);
}
// Get a message's content.
public static String getMessageContent(Message message)
throws Exception {
Object content = message.getContent();
if (content instanceof Multipart) {
StringBuffer messageContent = new StringBuffer();
Multipart multipart = (Multipart) content;
for (int i = 0; i < multipart.getCount(); i++) {
Part part = (Part) multipart.getBodyPart(i);
if (part.isMimeType("text/plain")) {
messageContent.append(part.getContent().toString());
}
}
return messageContent.toString();
} else {
return content.toString();
}
}
// Run the E-mail Client.
public static void main(String[] args) {
EmailClient client = new EmailClient();
client.show();
// Display connect dialog.
client.connect();
} }
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* This class displays a dialog for entering e-mail
server connection settings. */
public class ConnectDialog extends JDialog {
// These are the e-mail server types.
private static final String[] TYPES = {"pop3", "imap"};
// Combo box for e-mail server types.
private JComboBox typeComboBox;
// Server, username and SMTP server text fields.
private JTextField serverTextField, usernameTextField;
private JTextField smtpServerTextField;
// Password text field.
private JPasswordField passwordField;
// Constructor for dialog.
public ConnectDialog(Frame parent) {
// Call super constructor, specifying that dialog is modal.
super(parent, true);
// Set dialog title.
setTitle("Connect");
// Handle closing events.
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
actionCancel();
}
});
// Setup settings panel.
JPanel settingsPanel = new JPanel();
settingsPanel.setBorder(
BorderFactory.createTitledBorder("Connection Settings"));
GridBagConstraints constraints;
GridBagLayout layout = new GridBagLayout();
settingsPanel.setLayout(layout);
JLabel typeLabel = new JLabel("Type:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 0, 0);
layout.setConstraints(typeLabel, constraints);
settingsPanel.add(typeLabel);
typeComboBox = new JComboBox(TYPES);
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.WEST;
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 0, 5);
constraints.weightx = 1.0D;
layout.setConstraints(typeComboBox, constraints);
settingsPanel.add(typeComboBox);
JLabel serverLabel = new JLabel("Server:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 0, 0);
layout.setConstraints(serverLabel, constraints);
settingsPanel.add(serverLabel);
serverTextField = new JTextField(25);
constraints = new GridBagConstraints();
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 0, 5);
constraints.weightx = 1.0D;
layout.setConstraints(serverTextField, constraints);
settingsPanel.add(serverTextField);
JLabel usernameLabel = new JLabel("Username:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 0, 0);
layout.setConstraints(usernameLabel, constraints);
settingsPanel.add(usernameLabel);
usernameTextField = new JTextField();
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.WEST;
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 0, 5);
constraints.weightx = 1.0D;
layout.setConstraints(usernameTextField, constraints);
settingsPanel.add(usernameTextField);
JLabel passwordLabel = new JLabel("Password:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 5, 0);
layout.setConstraints(passwordLabel, constraints);
settingsPanel.add(passwordLabel);
passwordField = new JPasswordField();
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.WEST;
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 5, 5);
constraints.weightx = 1.0D;
layout.setConstraints(passwordField, constraints);
settingsPanel.add(passwordField);
JLabel smtpServerLabel = new JLabel("SMTP Server:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 5, 0);
layout.setConstraints(smtpServerLabel, constraints);
settingsPanel.add(smtpServerLabel);
smtpServerTextField = new JTextField(25);
constraints = new GridBagConstraints();
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 5, 5);
constraints.weightx = 1.0D;
layout.setConstraints(smtpServerTextField, constraints);
settingsPanel.add(smtpServerTextField);
// Setup buttons panel.
JPanel buttonsPanel = new JPanel();
JButton connectButton = new JButton("Connect");
connectButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionConnect();
}
});
buttonsPanel.add(connectButton);
JButton cancelButton = new JButton("Cancel");
cancelButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionCancel();
}
});
buttonsPanel.add(cancelButton);
// Add panels to display.
getContentPane().setLayout(new BorderLayout());
getContentPane().add(settingsPanel, BorderLayout.CENTER);
getContentPane().add(buttonsPanel, BorderLayout.SOUTH);
// Size dialog to components.
pack();
// Center dialog over application.
setLocationRelativeTo(parent);
}
// Validate connection settings and close dialog.
private void actionConnect() {
if (serverTextField.getText().trim().length() < 1
|| usernameTextField.getText().trim().length() < 1
|| passwordField.getPassword().length < 1
|| smtpServerTextField.getText().trim().length() < 1) {
JOptionPane.showMessageDialog(this,
"One or more settings is missing.",
"Missing Setting(s)", JOptionPane.ERROR_MESSAGE);
return;
}
// Close dialog.
dispose();
}
// Cancel connecting and exit program.
private void actionCancel() {
System.exit(0);
}
// Get e-mail server type.
public String getTypes() {
return (String) typeComboBox.getSelectedItem();
}
// Get e-mail server.
public String getServer() {
return serverTextField.getText();
}
// Get e-mail username.
public String getUsername() {
return usernameTextField.getText();
}
// Get e-mail password.
public String getPassword() {
return new String(passwordField.getPassword());
}
// Get e-mail SMTP server.
public String getSmtpServer() {
return smtpServerTextField.getText();
}
}
一旦我运行应用程序，我选择了imap，请关注我的电子邮件，密码和smtp
服务器：imap.gmail.com
用户名：********@gmail.com
密码：*************
smtp服务器：smtp.gmail.com
一旦按下连接就给了我这个错误
javax.mail.NoSuchProviderException: No provider for NORMAL
at javax.mail.Session.getProvider(Session.java:483)
at javax.mail.Session.getStore(Session.java:557)
at emailclient.EmailClient.connect(EmailClient.java:295)
at emailclient.EmailClient.main(EmailClient.java:369)
答案 0 :(得分：0)
问题是您正在调用dialog.getType()（java.awt.Window的一部分），而不是您在dialog.getTypes()中实施的方法ConnectDialog。因此，您无法获得预期的协议名称。方法getType()返回类型为java.awt.Window.Type的枚举值（在这种情况下，它返回java.awt.Window.Type.NORMAL，其toString()值使用NORMAL。
一些建议：尝试将ConnectDialog等用户界面对象与其模型分开（例如某种ConnectionInformation）。