断点续传下载 （JAVA版 迅雷）

package Download; import java.awt.BorderLayout; import java.awt.Color; import java.awt.Component; import java.awt.Graphics; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.Serializable; import java.util.ArrayList; import java.util.List; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.border.EmptyBorder; public class DownloadFrame extends JFrame { private static final int THREAD_NUM = 4; private List<DownloadItem> itemList = new ArrayList<DownloadItem>(); private transient InnerThread innerThread = new InnerThread(); private static final String downloadInfoFile = "downloadInfo"; public DownloadFrame() { setSize(500, 400); add(createContentPane()); setLocationRelativeTo(null); setResizable(false); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } public void init() { this.addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) { if (itemList != null && itemList.size() > 0) { for (DownloadItem item : itemList) { if (item.status == DownloadItem.STATUS_START) { item.stop(); } } } save(DownloadFrame.this); } }); if (itemList != null && itemList.size() > 0) { for (DownloadItem item : itemList) { item.setActionListener(); } } innerThread = new InnerThread(); innerThread.start(); } private Component createContentPane() { JPanel p = new JPanel(new BorderLayout()); p.setBackground(new Color(35, 31, 32)); p.add(BorderLayout.CENTER, createTabPane()); return p; } private JPanel createTabPane() { JPanel p = new JPanel(new GridLayout(10, 1, 6, 6)); p.setBackground(new Color(35, 31, 32)); p.setBorder(new EmptyBorder(8, 8, 8, 8)); for (int i = 0; i < THREAD_NUM; i++) { DownloadItem item = new DownloadItem(); // label JLabel label = new JLabel(); label.setForeground(Color.WHITE); item.label = label; // button JButton btn = new JButton(); btn.setForeground(new Color(249, 250, 251)); btn.setBackground(new Color(220, 31, 36)); item.button = btn; // progressPanel ProgressPanel pp = new ProgressPanel(); item.progressPanel = pp; // 布局 p.add(label); JPanel p1 = new JPanel(new BorderLayout(6, 6)); p1.setBackground(new Color(35, 31, 32)); p1.add(BorderLayout.EAST, btn); p1.add(BorderLayout.CENTER, pp); p.add(p1); item.init(); item.setActionListener(); itemList.add(item); } return p; } private class ProgressPanel extends JPanel { private int online; public ProgressPanel() { } @Override public void paint(Graphics g) { super.paint(g); for (int i = 0; i < online; i++) { g.fill3DRect(6 + i * 4, 8, 3, 16, true); } } } private class InnerThread extends Thread { public InnerThread() { setDaemon(true); } @Override public void run() { while (true) { try { for (int i = 0; i < itemList.size(); i++) { itemList.get(i).update(); } repaint(); Thread.sleep(50); } catch (InterruptedException e) { } } } } private class DownloadItem implements Serializable { private static final int STATUS_INIT = 1; private static final int STATUS_START = 2; private static final int STATUS_STOP = 3; ProgressPanel progressPanel; JLabel label; JButton button; DownloadInfo info; transient DownloadThread thread; int status; void setActionListener() { button.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { switch (status) { case STATUS_INIT: String url = JOptionPane.showInputDialog( "请输入下载地址"); if (url == null || url.length() == 0) break; String fileName = JOptionPane .showInputDialog("请输入保存文件路径"); if (fileName == null || url.length() == 0) break; File file = new File(fileName); try { file.createNewFile(); info = new DownloadInfo(url, fileName); thread = new DownloadThread(info); thread.start(); start(); } catch (IOException e1) { JOptionPane.showMessageDialog(DownloadFrame.this, "输入的文件路径有误"); break; } break; case STATUS_START: stop(); break; case STATUS_STOP: thread = new DownloadThread(info); thread.start(); start(); break; } } }); } void init() { status = STATUS_INIT; button.setText("选择"); label.setText("请选择要下载的文件"); } void start() { status = STATUS_START; button.setText("终止"); } void stop() { status = STATUS_STOP; thread.setStop(true); button.setText("开始"); } void update() { if (thread != null) { if (thread.isFinish()) { init(); label.setText("下载已经完成"); } else { if (info.getFileSize() != -1) { int percent = (int) (info.getPos() * 100 / info .getFileSize()); progressPanel.online = percent; label.setText("文件：" + info.getFileName() + "正在下载中："+ percent + "%"); } else { label.setText("文件：" + info.getFileName() + "正在下载中"); } } } } public DownloadItem() { } } public static void main(String[] args) { DownloadFrame frame = load(); if (frame == null) { frame = new DownloadFrame(); } frame.init(); frame.setVisible(true); } private static void save(DownloadFrame frame) { File file = new File(downloadInfoFile); System.out.println("save: " + file); try { ObjectOutputStream oos = new ObjectOutputStream( new FileOutputStream(file)); oos.writeObject(frame); oos.clo