大数据Java基础第二十天作业
Posted
tags:
篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了大数据Java基础第二十天作业相关的知识,希望对你有一定的参考价值。
第一题:多线程下载,显示下载进度条。(暂停功能个和断点续传待开发)。 import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JTextArea; import javax.swing.JButton; import javax.swing.JProgressBar; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.Component; import java.net.URL; import java.net.URLConnection; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.ByteArrayInputStream; import java.io.InputStream; import java.io.RandomAccessFile; import java.util.List; import java.util.ArrayList; import java.util.Properties; class Download{ private static final long serialVersionUID = -6944831795769317874L; public static void main(String[] args){ new DownloadWindow(); } } class DownloadWindow extends JFrame{ private JTextArea url_text; private JTextArea local_text; private JButton pause_button; private JProgressBar[] bar_arr; public boolean is_pause = false; private int every_count = 0; public DownloadWindow(){ ini(); } public void ini(){ this.setSize(600,400); this.setLocation(600,300); this.setLayout(null); JLabel url_label = new JLabel("URL : "); url_label.setBounds(10,10,100,20); this.add(url_label); url_text = new JTextArea(); url_text.setEditable(true); url_text.setBounds(100,10,400,20); this.add(url_text); JLabel local_label = new JLabel("Local : "); local_label.setBounds(10,40,100,20); this.add(local_label); local_text = new JTextArea(); local_text.setEditable(true); local_text.setBounds(100,40,400,20); this.add(local_text); JButton down_button = new JButton("Download"); down_button.setBounds(200,110,100,50); down_button.addMouseListener(new MouseAdapter(){ public void mouseClicked(MouseEvent e){ String src_url = url_text.getText(); String local_addr = local_text.getText(); DownloadManager manager = new DownloadManager(DownloadWindow.this,src_url,local_addr,5); addBar(manager.getListInfo()); manager.start(); } }); this.add(down_button); JButton pause_button = new JButton("Stop"); pause_button.setBounds(320,110,100,50); pause_button.addMouseListener(new MouseAdapter(){ public void mouseClicked(MouseEvent e){ DownloadWindow.this.is_pause = !DownloadWindow.this.is_pause; pause_button.setText(DownloadWindow.this.is_pause ? "Start" : "Stop"); String src_url = url_text.getText(); String local_addr = local_text.getText(); if(!DownloadWindow.this.is_pause){ List<DownloadInfo> info_list = new ArrayList<DownloadInfo>(); try{ ObjectInputStream ois = new ObjectInputStream(new FileInputStream(local_addr + ".tmp")); List<DownloadInfo> list = (List<DownloadInfo>)ois.readObject(); }catch(Exception ex){ ex.printStackTrace(); } DownloadManager manager = new DownloadManager(DownloadWindow.this,info_list); addBar(manager.getListInfo()); manager.start(); } } }); this.add(pause_button); this.setVisible(true); } public void addBar(List<DownloadInfo> info_list){ bar_arr = new JProgressBar[info_list.size()]; int y = 200; for(int i=0;i<info_list.size();i++){ DownloadInfo info = info_list.get(i); bar_arr[i] = new JProgressBar(); System.out.println("===" + info.getEndPos()); System.out.println("---" + info.getStartPos()); bar_arr[i].setMaximum(info.getEndPos() - info.getStartPos() + 1); bar_arr[i].setBounds(100,y + (i*25),400,10); this.add(bar_arr[i]); } this.repaint(); } public void updateBar(int length,int index){ int new_value = bar_arr[index].getValue() + length; System.out.println(new_value); bar_arr[index].setValue(new_value); if(new_value >= bar_arr[index].getMaximum()){ every_count ++; if(every_count >= bar_arr.length){ finishBar(); } } } public void finishBar(){ for(Component comp : bar_arr){ this.remove(comp); } this.repaint(); } } class DownloadManager{ private DownloadWindow window; private String src_url; private String local_addr; private int count; private DownloadInfo info; private List<DownloadInfo> info_list; public DownloadManager(DownloadWindow window,List<DownloadInfo> info_list){ this.window = window; this.info_list = info_list; } public DownloadManager(DownloadWindow window,String src_url,String local_addr,int count){ this.window = window; "http://blog.51cto.com/viewpic.php?refimg=" + this.src_url = src_url; this.local_addr = local_addr; this.count = count; prepareDownload(); } public void prepareDownload(){ info_list = new ArrayList<DownloadInfo>(); try{ URL url = new URL(src_url); int total_length = url.openConnection().getContentLength(); RandomAccessFile raf = new RandomAccessFile(local_addr,"rw"); raf.setLength(total_length); raf.close(); int block = total_length / count; DownloadInfo info = null; for(int i = 0;i < count;i++){ info = new DownloadInfo(); info.setIndex(i); info.setSrcUrl(src_url); info.setLocalAddr(local_addr); info.setStartPos(i * block); if((count - 1) == i){ info.setEndPos(total_length - 1); }else{ info.setEndPos((i + 1) * block - 1); } info_list.add(info); } }catch(Exception e){ e.printStackTrace(); } } private List<DownloadInfo> readListInfo(File tmp_file){ List<DownloadInfo> info_list = new ArrayList<DownloadInfo>(); try{ Properties prop = new Properties(); prop.load(new FileInputStream(tmp_file)); String tmp_url = prop.getProperty("url"); int count = Integer.parseInt(prop.getProperty("count")); DownloadInfo info = null; for(int i=0;i<count;i++){ String value = prop.getProperty("Thread." + i); String[] arr = value.split(";"); info = new DownloadInfo(); info.setIndex(i); info.setSrcUrl(tmp_url); info.setStartPos(Integer.parseInt(arr[0])); info.setEndPos(Integer.parseInt(arr[1])); info.setAmount(Integer.parseInt(arr[2])); String path = tmp_file.getAbsolutePath(); path = path.substring(0,path.lastIndexOf(".")); info.setLocalAddr(path); info_list.add(info); } return info_list; }catch(Exception e){ e.printStackTrace(); } return null; } public void start(){ for(DownloadInfo info : info_list){ try{ DownloadThread s = new DownloadThread(window,info); s.start(); s.join(); }catch(Exception e){ e.printStackTrace(); } } if(window.is_pause){ try{ FileOutputStream fos = new FileOutputStream(local_addr + ".tmp"); ObjectOutputStream oos = new ObjectOutputStream(fos); oos.writeObject(info_list); }catch(Exception e){ e.printStackTrace(); } } } public List<DownloadInfo> getListInfo(){ return info_list; } } class DownloadThread extends Thread{ private DownloadWindow window; private DownloadInfo info; public DownloadThread(DownloadWindow window,DownloadInfo info){ this.window = window; this.info = info; } public void run(){ try{ URL url = new URL(info.getSrcUrl()); URLConnection connect = url.openConnection(); connect.setRequestProperty("Range","bytes=" + info.getStartPos() + "-" + info.getEndPos()); InputStream in = connect.getInputStream(); RandomAccessFile raf = new RandomAccessFile(info.getLocalAddr(),"rw"); raf.seek(info.getEndPos()); byte[] buf = new byte[1024]; int length = 0; while((length = in.read(buf)) != -1){ System.out.println(length + "++" + info.getIndex()); raf.write(buf,0,length); window.updateBar(length,info.getIndex()); Thread.sleep(2000); if(window.is_pause){ break; } } raf.close(); }catch(Exception e){ e.printStackTrace(); } } } class DownloadInfo{ private String src_url; private String local_addr; private int start_pos; private int end_pos; private int index; private int amount; public DownloadInfo(){ } public DownloadInfo(String src_url,String local_addr,int start_pos,int end_pos){ "http://blog.51cto.com/viewpic.php?refimg=" + this.src_url = src_url; this.local_addr = local_addr; this.start_pos = start_pos; this.end_pos = end_pos; } public String getSrcUrl(){ return src_url; } public void setSrcUrl(String src_url){ "http://blog.51cto.com/viewpic.php?refimg=" + this.src_url = src_url; } public String getLocalAddr(){ return local_addr; } public void setLocalAddr(String local_addr){ this.local_addr = local_addr; } public int getStartPos(){ return start_pos; } public void setStartPos(int start_pos){ this.start_pos = start_pos; } public int getEndPos(){ return end_pos; } public void setEndPos(int end_pos){ this.end_pos = end_pos; } public int getIndex(){ return index; } public void setIndex(int index){ this.index = index; } public int getAmount(){ return amount; } public void setAmount(int amount){ this.amount = amount; } }
本文出自 “森林敏” 博客,请务必保留此出处http://senlinmin.blog.51cto.com/6400386/1793104
以上是关于大数据Java基础第二十天作业的主要内容,如果未能解决你的问题,请参考以下文章