Java多執行緒下載網路檔案
新建一個JavaGUI介面
package Download;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JOptionPane;
import javax.swing.JComboBox;
// 測試下載地址 https://d1.music.126.net/dmusic/cloudmusicsetup_2.5.2.196939.exe
public class ThreadDownLoadGUI extends JFrame implements ActionListener{
private int num=1;
private JPanel contentPane;
private JTextField textField;
private JTextField textField_1;
private String name;
private static int index;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
ThreadDownLoadGUI frame = new ThreadDownLoadGUI();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public ThreadDownLoadGUI() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 703, 238);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JLabel lblPath = new JLabel("Path:");
lblPath.setFont(new Font("Arial Black", Font.ITALIC, 24));
lblPath.setBounds(14, 13, 72, 26);
contentPane.add(lblPath);
textField = new JTextField();
textField.setFont(new Font("宋體", Font.PLAIN, 26));
textField.setBounds(102, 13, 467, 30);
contentPane.add(textField);
textField.setText("https://d1.music.126.net/dmusic/cloudmusicsetup_2.5.2.196939.exe");
textField.setColumns(10);
JLabel lblSavepath = new JLabel("SavePath:");
lblSavepath.setFont(new Font("Arial Black", Font.ITALIC, 24));
lblSavepath.setBounds(14, 88, 140, 30);
contentPane.add(lblSavepath);
textField_1 = new JTextField();
textField_1.setEnabled(false);
textField_1.setFont(new Font("仿宋", Font.ITALIC, 24));
textField_1.setBounds(153, 88, 436, 40);
contentPane.add(textField_1);
textField_1.setColumns(10);
JButton btnFind = new JButton("Find");
btnFind.setBounds(603, 88, 68, 40);
btnFind.setActionCommand("open");
btnFind.addActionListener(this);
contentPane.add(btnFind);
String ThreadNum[]= {"1","2","3","4","5"};
JComboBox comboBox = new JComboBox(ThreadNum);
comboBox.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
num=Integer.parseInt((String) comboBox.getSelectedItem());
}
});
comboBox.setBounds(581, 16, 37, 30);
contentPane.add(comboBox);
JLabel label = new JLabel("\u4E2A\u7EBF\u7A0B");
label.setBounds(617, 18, 68, 27);
contentPane.add(label);
JButton button = new JButton("\u5F00\u59CB\u4E0B\u8F7D");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String url=textField.getText();
name=textField_1.getText();
if(name==null||name.equals("")) {
JOptionPane.showMessageDialog(null, "儲存地址無效");
return;
}else {
downloadTest(url);
}
}
});
button.setBounds(286, 151, 113, 27);
contentPane.add(button);
}
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(e.getActionCommand().equals("open")) {
JFileChooser jf = new JFileChooser();
jf.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
int flag=-1;
String savePath=null;
try {
flag=jf.showOpenDialog(this);
}catch(Exception e1) {
e1.printStackTrace();
}finally {
if(flag==JFileChooser.APPROVE_OPTION) { //如果是確定按鈕
File f=jf.getSelectedFile();
savePath=f.getAbsolutePath();
}
}
if(savePath!=null) {
textField_1.setText(savePath);
}
}
}
public void downloadTest(String url) {
InputStream io=null;
BufferedInputStream bio=null;
BufferedOutputStream bpo=null;
HttpURLConnection con=null;
try {
URL file=new URL(url);
String path=file.getPath();
name=path.substring(path.lastIndexOf("/")+1);
con=(HttpURLConnection)file.openConnection();
con.connect();
if(!(con.getResponseCode()==200)) {
JOptionPane.showMessageDialog(null, "地址無效");
return;
}else {
io=con.getInputStream();
bio=new BufferedInputStream(io);
long fileLength=con.getContentLengthLong();
String savePath=textField_1.getText();
new ThreadsDownLoad(url, savePath, num, fileLength, name).start();
}
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
try {
if(bio!=null) {
bio.close();
}
if(bpo!=null) {
bpo.close();
}
if(con!=null) {
con.disconnect();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
//測試下載地址 https://d1.music.126.net/dmusic/cloudmusicsetup_2.5.2.196939.exe 網易雲音樂
//多執行緒下載類
package Download;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import javax.swing.JOptionPane;
public class ThreadsDownLoad extends Thread{
private String url,savePath;
private int ThreadNum=1;
private String name;
private final long totalLength;
private static int index=0;
public ThreadsDownLoad(String url,String savePath,int ThreadNum,long totalLength,String name) {
this.url=url;
this.savePath=savePath;
this.ThreadNum=ThreadNum;
this.totalLength=totalLength;
this.name=name;
}
@Override
public void run() {
// TODO Auto-generated method stub
long length=totalLength/ThreadNum;
long mod=totalLength%length;
for(int i=0;i<ThreadNum;i++) {
long start=i*length;
long end;
if(i<ThreadNum-1) {
end=(i+1)*length-1;
}else {
end=(i+1)*length+mod;
}
downloadTest(start,end,end-start+1);
}
}
//方法1：限制獲取網路資源的長度
public void downloadTest(long start,long end,long fileLength) {
InputStream io=null;
BufferedInputStream bio=null;
HttpURLConnection con=null;
RandomAccessFile ace=null;
File save=new File(savePath,name);
try {
ace=new RandomAccessFile(save,"rw");
ace.seek(start);
URL link=new URL(url);
con=(HttpURLConnection)link.openConnection();
con.setRequestProperty("Range", "bytes="+start+"-"+end); //[start,end] 限制獲取網路資源的長度
con.connect();
io=con.getInputStream();
bio=new BufferedInputStream(io);
int len;
byte[] by=new byte[1024];
while((len=bio.read(by))!=-1) {
ace.write(by, 0, len);
}
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
try {
if(bio!=null) {
bio.close();
}
if(ace!=null) {
ace.close();
}
if(con!=null) {
con.disconnect();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}