Java Socket編程 - 基于TCP方式的二進制文件傳輸
一個基于Java Socket協議之上文件傳輸的完整示例，基于TCP通信完成。
除了基于TCP的二進制文件傳輸，還演示了JAVA Swing的一些編程技巧，Demo程序
實現主要功能有以下幾點：
1. 基于Java Socket的二進制文件傳輸(包括圖片，二進制文件，各種文檔work，
PDF)
2. SwingWorker集合JProgressBar顯示實時傳輸/接受完成的百分比
3. 其它一些Swing多線程編程技巧
首先來看一下整個Dome的Class之間的關系圖：
下面按照上圖來詳細解釋各個類的功能與代碼實現：
服務器端：
FileTransferServer類的功能首先是在端口9999創建一個服務器套接字并
開始監聽連接。相關代碼如下：
private void startServer(int port) {
try {
serverSocket = new ServerSocket(port);
System.out.println("Server started at port :" + port);
while(true) {
Socket client = serverSocket.accept(); // blocked & waiting for income socket
System.out.println("Just connected to " + client.getRemoteSocketAddress());
FileReceiveTask task = new FileReceiveTask(client);
bar.setValue(0); // reset it now
task.addPropertyChangeListener(new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
if ("progress".equals(evt.getPropertyName())) {
bar.setValue((Integer) evt.getNewValue());
}
}
});
task.execute();
}
} catch (IOException e) {
e.printStackTrace();
}
}</pre>關于PropertyChangeListener, Java提供了一個非常有力的工具類來
監控任意Bean Model的數據改變，程序通過添加該監聽器實現對
SwingWorker的progress屬性值改變的事件捕獲，然后更新JProgressBar
實例對象，實現了UI的刷新。FileTransferServer類的完整源代碼如下：
package com.gloomyfish.socket.tutorial.filetransfer;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
public class FileTransferServer extends JFrame implements ActionListener {
/**
*
*/
public final static String START_SVR = "Start";
public final static String SHUT_DOWN_SVR = "Shut Down";
public final static String END_FLAG = "EOF";
private static final long serialVersionUID = 1L;
private ServerSocket serverSocket;
private JButton startBtn;
private JProgressBar bar;
public FileTransferServer() {
super("File Server");
initComponent();
setupListener();
}
private void setupListener() {
startBtn.addActionListener(this);
}
private void initComponent() {
startBtn = new JButton(START_SVR);
JPanel progressPanel = new JPanel();
progressPanel.setLayout(new BoxLayout(progressPanel, BoxLayout.Y_AXIS));
bar = new JProgressBar();
bar.setMinimum(0);
bar.setMaximum(100);
progressPanel.add(bar);
getContentPane().setLayout(new BorderLayout());
JPanel btnPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
btnPanel.add(startBtn);
getContentPane().add(btnPanel, BorderLayout.SOUTH);
getContentPane().add(progressPanel, BorderLayout.CENTER);
}
private void startServer(int port) {
try {
serverSocket = new ServerSocket(port);
System.out.println("Server started at port :" + port);
while(true) {
Socket client = serverSocket.accept(); // blocked & waiting for income socket
System.out.println("Just connected to " + client.getRemoteSocketAddress());
FileReceiveTask task = new FileReceiveTask(client);
bar.setValue(0); // reset it now
task.addPropertyChangeListener(new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
if ("progress".equals(evt.getPropertyName())) {
bar.setValue((Integer) evt.getNewValue());
}
}
});
task.execute();
}
} catch (IOException e) {
e.printStackTrace();
}
}
public void showSuccess() {
bar.setValue(100);
JOptionPane.showMessageDialog(this, "file received successfully!");
}
@Override
public void actionPerformed(ActionEvent e) {
if(START_SVR.equals(e.getActionCommand())) {
Thread startThread = new Thread(new Runnable() {
public void run() {
startServer(9999);
}
});
startThread.start();
startBtn.setEnabled(false);
} else if(SHUT_DOWN_SVR.equals(e.getActionCommand())) {
} else {
// do nothing...
}
}
public static void main(String[] args) {
FileTransferServer server = new FileTransferServer();
server.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
server.setSize(400, 400);
server.setResizable(false);
server.setVisible(true);
}
}</pre>FileReceiveTask是服務器端的文件接受類：
首先從建立的TCP流中得到文件名與文件大小，然后開始接受文件內容字節
并寫入創建的文件對象流中，最后驗證文件大小與寫入的字節流是否相等
最后發送一條消息到文件發送方，告訴對方文件傳輸完成，可以關閉TCP流。
該類的完整源代碼如下：
package com.gloomyfish.socket.tutorial.filetransfer;
import java.io.BufferedOutputStream;
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.net.Socket;
import javax.swing.SwingWorker;
public class FileReceiveTask extends SwingWorker<Integer, Object> {
private Socket _mSocket;
public FileReceiveTask(Socket client) {
this._mSocket = client;
}
@Override
protected Integer doInBackground() throws Exception {
// get file meta information
DataInputStream input = new DataInputStream(_mSocket.getInputStream());
String fileName = input.readUTF();
int fileLength = (int)input.readLong(); // number of total bytes
File file = new File("C:\\Users\\fish\\Downloads" + File.separator + fileName);
BufferedOutputStream output = new BufferedOutputStream(new FileOutputStream(file));
System.out.println("Received File Name = " + fileName);
System.out.println("Received File size = " + fileLength/1024 + "KB");
// start to receive the content of the file and write them
byte[] content = new byte[2048];
int offset = 0;
int numReadBytes = 0;
while(offset < fileLength && (numReadBytes = input.read(content)) > 0) {
output.write(content, 0, numReadBytes);
float precent = 100.0f * ((float)offset)/((float)fileLength);
setProgress((int)precent);
offset += numReadBytes;
}
System.out.println("numReadBytes = " + numReadBytes);
if(offset < fileLength) {
numReadBytes = input.read(content);
System.out.println("numReadBytes = " + numReadBytes);
System.out.println("File content error at server side");
} else {
System.out.println("File Receive Task has done correctly");
}
setProgress(100);
// tell client to close the socket now, we already receive the file successfully!!
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(_mSocket.getOutputStream()));
bufferedWriter.write("DONE\r\n");
bufferedWriter.flush();
// close the file and socket
output.close();
_mSocket.close();
return 100;
}
}</pre>客戶端：
FileTransferClient是客戶端UI類，用來實現到服務端的連接，然后選擇
要傳輸的文件(圖片，PDF，Word文檔等各種二進制文件)。如果沒有
輸入服務器信息，會彈出提示要求輸入。端口已經指定為：9999
【send File】按鈕會打開文件選擇框，用戶選擇要傳輸文件以后，創建
FileTransferTask線程，并開始執行文件傳送。客戶端UI代碼如下：
package com.gloomyfish.socket.tutorial.filetransfer;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.JTextField;
/**
- 我一般寫英文注釋，偶爾我也會寫中文注釋，只是覺得寫英文
- 注釋跟代碼比較統一，無他。
- @Date 2012-11-30
@author fish / public class FileTransferClient extends JFrame implements ActionListener { /**
*/ private static final long serialVersionUID = 1L; public final static String SEND_CMD = "Send File"; public final static int MINIMUM = 0; public final static int MAXIMUM = 100; // public final static String CONNECT_CMD = "Connect"; private JButton sendFileBtn; private JTextField serverField; private JTextField portField; private JProgressBar bar;
public FileTransferClient() { super("File Transfer Client"); initComponents(); }
private void initComponents() { getContentPane().setLayout(new BorderLayout()); JPanel progressPanel = new JPanel(); progressPanel.setLayout(new BoxLayout(progressPanel, BoxLayout.Y_AXIS)); bar = new JProgressBar(); progressPanel.add(bar); bar.setMinimum(MINIMUM); bar.setMaximum(MAXIMUM); JPanel serverSettingPanel = new JPanel(); serverSettingPanel.setLayout(new GridLayout(2,2,5,5)); serverSettingPanel.setBorder(BorderFactory.createTitledBorder("Server Setting")); serverField = new JTextField(); portField = new JTextField(); serverSettingPanel.add(new JLabel("Server IP/Host:")); serverSettingPanel.add(serverField); serverSettingPanel.add(new JLabel("Server Port:")); serverSettingPanel.add(portField);
sendFileBtn = new JButton(SEND_CMD); JPanel btnPanel = new JPanel(); btnPanel.setLayout(new FlowLayout(FlowLayout.RIGHT)); btnPanel.add(sendFileBtn); getContentPane().add(serverSettingPanel, BorderLayout.NORTH); getContentPane().add(btnPanel, BorderLayout.SOUTH); getContentPane().add(progressPanel, BorderLayout.CENTER); sendFileBtn.addActionListener(this); }
@Override public void actionPerformed(ActionEvent e) { String command = e.getActionCommand(); if(command.equals(SEND_CMD)) {
if(checkNull()) { JOptionPane.showMessageDialog(this, "Please enter server host and port in order to set up the connection!"); return; } JFileChooser chooser = new JFileChooser(); int status = chooser.showOpenDialog(null); if (status == JFileChooser.APPROVE_OPTION) { File f = chooser.getSelectedFile(); SocketAddress address = new InetSocketAddress(getServer(), getPort()); FileTransferTask task = new FileTransferTask(f, address, this); bar.setValue(0); task.addPropertyChangeListener(new PropertyChangeListener() { public void propertyChange(PropertyChangeEvent evt) { if ("progress".equals(evt.getPropertyName())) { bar.setValue((Integer) evt.getNewValue()); } } }); task.execute(); // 異步task執行 }} else {
// do nothing} }
public void showSuccess() { bar.setValue(100); JOptionPane.showMessageDialog(this, "file send successfully!"); }
public String getServer() { return serverField.getText().trim(); }
public int getPort() { return Integer.parseInt(portField.getText().trim()); } /**
- make sure the UI already have some correct input information here!!!
@return */ private boolean checkNull() { String serverName = serverField.getText(); String port = portField.getText(); if(serverName == null || serverName.length() == 0 || port == null || port.length() == 0) {
return true;}
try {
Integer.parseInt(port); // try to parse it as server port number , validation code.} catch(NumberFormatException ne) {
ne.printStackTrace(); return true;} return false; }
public static void main(String[] args) { FileTransferClient client = new FileTransferClient(); client.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); client.setSize(400, 400); client.setResizable(false); // client.pack(); client.setVisible(true); }
}</pre>FileTransferTask實現的功能主要有：
1. 發送文件meta信息到接受方(文件名與文件大小)
2. 讀取文件內容字節寫入Socket字節流中，發送到接受方
3. 從Socket字節流中讀取對方接受完成通知信息，調用彈出文件傳輸成功信息
該類完全源代碼如下：
package com.gloomyfish.socket.tutorial.filetransfer;import java.io.BufferedInputStream; import java.io.BufferedReader; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStreamReader; import java.net.Socket; import java.net.SocketAddress;
import javax.swing.SwingWorker;
public class FileTransferTask extends SwingWorker<Integer, Object> { private File selectedFile; private Socket mSocket; private SocketAddress address; private FileTransferClient parent;
public FileTransferTask(File file, SocketAddress address, FileTransferClient owner /*, JProgressBar progress*/) { this.address = address; this.selectedFile = file; mSocket = new Socket(); this.parent = owner; } @Override protected Integer doInBackground() throws Exception { // Get the size of the file long length = selectedFile.length(); if (length > Integer.MAX_VALUE) { throw new IOException("Could not completely read file " + selectedFile.getName() + " as it is too long (" + length + " bytes, max supported " + Integer.MAX_VALUE + ")"); } mSocket.connect(address); // Create the byte array to hold the file data mSocket.setSoLinger(true, 60); DataOutputStream dout = new DataOutputStream(mSocket.getOutputStream()); // now we start to send the file meta info. dout.writeUTF(selectedFile.getName()); dout.writeLong(length); dout.flush(); // end comment FileDataPackage pData = new FileDataPackage(); DataInputStream is = new DataInputStream(new FileInputStream(selectedFile)); byte[] bytes = new byte[2048]; // Read in the bytes int offset = 0; int numRead = 0; int fsize = (int)length; while (offset < fsize && (numRead=is.read(bytes, 0, bytes.length)) >= 0) { pData.setData(bytes, numRead); dout.write(pData.getPackageData(), 0, pData.getPackageData().length); dout.flush(); offset += numRead; float precent = 100.0f * ((float)offset)/((float)fsize); setProgress((int)precent); } System.out.println("total send bytes = " + offset); // Ensure all the bytes have been read in if (offset < fsize) { throw new IOException("Could not completely transfer file " + selectedFile.getName()); } mSocket.shutdownOutput(); // receive the file transfer successfully message from connection BufferedInputStream streamReader = new BufferedInputStream(mSocket.getInputStream()); BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(streamReader)); String doneMsg = bufferedReader.readLine(); if("DONE".equals(doneMsg)) { parent.showSuccess(); } // Close the file input stream setProgress(100); // dout.close(); mSocket.close(); is.close(); System.out.println("close it now......"); return 100; }}</pre>數據包類如下，不解釋！
package com.gloomyfish.socket.tutorial.filetransfer; /**
- this is very simple file transfer protocol over TCP socket
- @date 2012-12-01
@author zhigang jia / public class FileDataPackage {
private int dataLength; // 數據包中數據長度，兩個字節 private byte[] databuff; // 數據包中數據，meici最大不超過2048字節
public final static byte[] EOF = new byte[]{'E', 'O','F'};
public FileDataPackage() {
dataLength = 0; databuff = new byte[2048];}
public byte[] getPackageData() {
byte[] pData = new byte[dataLength]; // end comment System.arraycopy(databuff, 0, pData, 0, dataLength); return pData;}
public void setData(byte[] data, int bsize) {
dataLength = bsize; for(int i=0; i<databuff.length; i++) { if(i<bsize) { databuff[i] = data[i]; } else { databuff[i] = ' '; } }} }</pre>每次發送的最大字節數為2048個字節。程序最終運行效果如下(win7 + JDK6u30)：
來自：http://blog.csdn.net/jia20003/article/details/8248221