这是我的主要课程：
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.UIManager.LookAndFeelInfo;
import java.io.*;
import java.lang.Process.*;
public class FTP {
public static void main (String []args)
{
Runnable runner = new Runnable(){
public void run()
{
LookAndFeel nimbusLook = new LookAndFeel();
nimbusLook.NimbusLookAndFeel();
JFrame frame = new JFrame("BNA FTP Diagnose");
frame.setVisible(true);
frame.setResizable(false);
frame.setSize(540, 420);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocation(150, 150);
JMenuBar menuBar = new JMenuBar();
frame.setJMenuBar(menuBar);
JMenu fileMenu = new JMenu("File");
menuBar.add(fileMenu);
final JMenuItem exitMenuItem = new JMenuItem("Exit");
fileMenu.add(exitMenuItem);
JMenu helpMenu = new JMenu("Help");
menuBar.add(new JPanel());
menuBar.add(helpMenu);
final JMenuItem aboutMenuItem = new JMenuItem("About");
helpMenu.add(aboutMenuItem);
JPanel titlePanel = new JPanel(new BorderLayout());
frame.add(titlePanel, BorderLayout.NORTH);
JLabel titleLabel = new JLabel("FTP Diagnose", JLabel.CENTER);
titleLabel.setFont(new Font(null, Font.BOLD, 14));
titleLabel.setForeground(Color.BLUE);
titlePanel.add(titleLabel);
JPanel gridPanel = new JPanel(new GridLayout(1, 1));
frame.add(gridPanel);
JPanel vendorPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
gridPanel.add(vendorPanel);
final String vendor [] = {"LLesiant" ,"WK-CCH", "Proquest", "Notes", "Research Institute of America", "Thomson",
"BNAI PDF Processing", " TM Portfolios to Indexing", "Postscript to PRODLOGIN1", "www.firstdoor.net", "psp.bna.com", "WEST", "LexisNexis", "McArdle Printing Company",
"Breaking News Email", "Ex Libris", "Pandora", "Bloomberg Law", "Acquire Media Site 1", "Acquire Media Site 2", "Quicksite", "QA Quicksite"};
final JComboBox vendorList = new JComboBox(vendor);
vendorPanel.add(vendorList);
JPanel diagnoseButtonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
gridPanel.add(diagnoseButtonPanel);
final JButton diagnoseButton = new JButton("Diagnose");
diagnoseButtonPanel.add(diagnoseButton);
JPanel centerPanel = new JPanel(new BorderLayout());
frame.add(centerPanel, BorderLayout.SOUTH);
JPanel commandPanel = new JPanel(new GridLayout(1, 0));
centerPanel.add(commandPanel);
final JTextArea commandResultArea = new JTextArea(7, 0);
JScrollPane scroll = new JScrollPane(commandResultArea, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
commandPanel.add(scroll);
commandResultArea.setEditable(false);
ActionListener buttonListener = new ActionListener(){
public void actionPerformed(ActionEvent ae)
{
int selectedIndex = vendorList.getSelectedIndex();
String llesiant = "ftp.llesiant.com";
String wkCCH = "FTP1.cch.com";
String proquest = "ftp.proquest.com";
String notes = "notes5.bna.com";
//String lineThree = null;
CommandClass readCommand = new CommandClass();
if (selectedIndex == 0)
{
commandResultArea.setText(readCommand.getCommand(llesiant)); //these return strings
}
else if (selectedIndex == 1)
{
commandResultArea.setText(readCommand.getCommand(wkCCH));
}
else if (selectedIndex == 2)
{
commandResultArea.setText(readCommand.getCommand(proquest));
}
else if (selectedIndex == 3)
{
commandResultArea.setText(readCommand.getCommand(notes));
}
}
};
diagnoseButton.addActionListener(buttonListener);
ActionListener exitListener = new ActionListener (){
public void actionPerformed(ActionEvent el)
{
if (el.getSource()== exitMenuItem)
{
JOptionPane.showMessageDialog(null, "FTP Program will exit now!");
System.exit(0);
}
}
};
exitMenuItem.addActionListener(exitListener);
ActionListener aboutListener = new ActionListener()
{
public void actionPerformed(ActionEvent al)
{
if (al.getSource()== aboutMenuItem)
{
JOptionPane.showMessageDialog(null, "This Software was made for Editors to. \nDiagnose BNA Bloomberg client FTP site.");
}
}
};
aboutMenuItem.addActionListener(aboutListener);
}
};
EventQueue.invokeLater(runner);
}
}
Here is my Look and feel class:
import javax.swing.UIManager;
import javax.swing.UIManager.LookAndFeelInfo;
public class LookAndFeel {
public void NimbusLookAndFeel()
{
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception e) {
// If Nimbus is not available, you can set the GUI to another look and feel.
}
}
}
Here is my CommandClass:
import java.io.IOException;
import java.io.InputStreamReader;
import javax.swing.JOptionPane;
public class CommandClass {
public String getCommand(String ftpSite){
String command = "ftp ";
StringBuffer output = new StringBuffer();
try{
Process p = Runtime.getRuntime().exec(command +ftpSite);
InputStreamReader ir = new InputStreamReader (p.getInputStream());
int outputChar = 0;
while((outputChar = ir.read()) != -1){
output.append((char)outputChar);
if(!ir.ready()){ // If the next read is not guarenteed, come out of loop.
break;
}
}
ir.close();
JOptionPane.showMessageDialog(null, "FTP is connected");
}catch (IOException e){
e.printStackTrace();
}
return output.toString();
}
}
我有这个FTP GUI，它假设连接到FTP站点并返回状态。如果已连接，则显示连接提示。
我建立了JTextArea以显示建立FTP连接时的消息，但是当它没有连接到ftp网站时，例如我的第4个ftp网站notes5.bna.com，它会冻结程序。另外一个小问题是如果你有一个程序FTP到这样的网站“shlfsdklaflkhasdlhfas”。仅在JOptionPane显示FTP已连接后才返回ftp站点。我不确定它有什么问题。
答案 0 :(得分：3)
notes5.bna.com冻结的原因是网站没有响应FTP连接请求。由于您只是使用Runtime#exec建立连接，因此将无限期地阻止响应。考虑使用3个 rd 方FTP客户端，例如Apache FTPClient，它允许您指定连接超时。
相关问题是某些网站正在申请用户名＆amp;访问密码。再次FTPClient允许您提供登录详细信息。
最后但同样重要的是，不要让重量级的非UI任务冻结你的Swing应用程序。 Swing有处理这些问题的机制，例如SwingWorker objects。