简单java下载程序

import java.util.*; import java.awt.*; import java.awt.event.*; import java.net.*; import javax.swing.*; import javax.swing.event.*; public class DownloadManager extends JFrame implements Observer { private JTextField addTextField; private DownloadsTableModel tableModel; private JTable table; private JButton pauseButton, resumButton, cancelButton, clearButton; private Download selectDownload; private boolean clearing; public DownloadManager() { setTitle("Download Manager"); setSize(640, 480); addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { actionExit(); } }); 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); JPanel addPanel = new JPanel(); addTextField = new JTextField(30); addPanel.add(addTextField); JButton addButton = new JButton("Add Download"); addButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { actionAdd(); } }); addPanel.add(addButton); // JFileChooser jfChooser = new JFileChooser(); // jfChooser.setDialogTitle("Save"); // addPanel.add(jfChooser); // JButton selectDirButton = new JButton("Save Dir"); // selectDirButton.addActionListener(new ActionListener(){ // public void actionPerformed(ActionEvent e){ // actionSelect(); // } // }); // addPanel.add(selectDirButton); tableModel = new DownloadsTableModel(); table = new JTable(tableModel); table.getSelectionModel().addListSelectionListener( new ListSelectionListener() { public void valueChanged(ListSelectionEvent e) { tableSelectionChange(); } }); table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); ProgressRenderer renderer = new ProgressRenderer(0, 100); renderer.setStringPainted(true); table.setDefaultRenderer(ProgressRenderer.class, renderer); table.setRowHeight((int) renderer.getPreferredSize().getHeight()); JPanel downloadsPanel = new JPanel(); downloadsPanel.setBorder(BorderFactory.createTitledBorder("Download")); downloadsPanel.setLayout(new BorderLayout()); downloadsPanel.add(new JScrollPane(table), BorderLayout.CENTER); JPanel buttonPanel = new JPanel(); pauseButton = new JButton("Pause"); pauseButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { actionPause(); } }); pauseButton.setEnabled(false); buttonPanel.add(pauseButton); resumButton = new JButton("Resum"); resumButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { actionResum(); } }); resumButton.setEnabled(false); buttonPanel.add(resumButton); cancelButton = new JButton("Cancel"); cancelButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { actionCancel(); } }); cancelButton.setEnabled(false); buttonPanel.add(cancelButton); clearButton = new JButton("Clear"); clearButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { actionClear(); } }); clearButton.setEnabled(false); buttonPanel.add(clearButton); getContentPane().setLayout(new BorderLayout()); getContentPane().add(addPanel, BorderLayout.NORTH); getContentPane().add(downloadsPanel, BorderLayout.CENTER); getContentPane().add(buttonPanel, BorderLayout.SOUTH); } private void actionExit() { System.exit(0); } private void actionAdd() { URL verifiedUrl = verfyUrl(addTextField.getText()); if (verifiedUrl != null) { JFileChooser fc = new JFileChooser(); fc.showSaveDialog(this); tableModel.addDownLoad(new Download(verifiedUrl,fc.getSelectedFile())); addTextField.setText(""); } else { JOptionPane.showMessageDialog(this, "Invalid Download Url", "Error", JOptionPane.ERROR_MESSAGE); } } private URL verfyUrl(String url) { if (!url.toLowerCase().startsWith("http://")) return null; URL verifiedUrl = null; try { verifiedUrl = new URL(url); } catch (Exception e) { return null; } if (verifiedUrl.getFile().length() < 2) return null; return verifiedUrl; } private void tableSelectionChange() { if (selectDownload != null) { selectDownload.deleteObserver(DownloadManager.this); } if (!clearing) { selectDownload = tableModel.getDownload(table.getSelectedRow()); selectDownload.addObserver(DownloadManager.this); updateButtons(); } } // private void actionSelect(){ // // } private void actionPause() { selectDownload.pause(); updateButtons(); } private void actionResum() { selectDownload.resum(); updateButtons(); } private void actionCancel() { selectDownload.cancel(); updateButtons(); } private void actionClear() { clearing = true; tableModel.cleanDownload(table.getSelectedRow()); clearing = false; selectDownload = null; updateButtons(); } private void updateButtons() { if (selectDownload != null) { int status = selectDownload.getStatus(); switch (status) { case Download.DOWNLOADING: pauseButton.setEnabled(true); resumButton.setEnabled(false); cancelButton.setEnabled(true); clearButton.setEnabled(false); break; case Download.PAUSED: pauseButton.setEnabled(false); resumButton.setEnabled(true); cancelButton.setEnabled(true); clearButton.setEnabled(false); break; case Download.ERROR: pauseButton.setEnabled(false); resumButton.setEnabled(true); cancelButton.setEnabled(false); clearButton.setEnabled(true); break; default: pauseButton.setEnabled(false); resumButton.setEnabled(false); cancelButton.setEnabled(false); clearButton.setEnabled(true); } }else{ pauseButton.setEnabled(false); resumButton.setEnabled(false); cancelButton.setEnabled(false); clearButton.setEnabled(false); } } public void update(Observable o, Object arg) { if(selectDownload!=null&&selectDownload.equals(o)){ updateButtons(); } } /** * @param args */ public static void main(String[] args) { DownloadManager manager = new DownloadManager(); manager.show(); } }