Java Socket实战之七 使用Socket通信传输文件

前面几篇文章介绍了使用Java的Socket编程和NIO包在Socket中的应用，这篇文章说说怎样利用Socket编程来实现简单的文件传输。

这里由于前面一片文章介绍了NIO在Socket中的应用，所以这里在读写文件的时候也继续使用NIO包，所以代码看起来会比直接使用流的方式稍微复杂一点点。

下面的示例演示了客户端向服务器端发送一个文件，服务器作为响应给客户端会发一个文件。这里准备两个文件E:/test/server_send.log和E:/test/client.send.log文件，在测试完毕后在客户端和服务器相同目录下会多出两个文件E:/test/server_receive.log和E:/test/client.receive.log文件。

下面首先来看看Server类，主要关注其中的sendFile和receiveFile方法。

[java] view plaincopyprint?

1. package com.googlecode.garbagecan.test.socket.nio; 
2.  
3. import java.io.File; 
4. import java.io.FileInputStream; 
5. import java.io.FileOutputStream; 
6. import java.io.IOException; 
7. import java.net.InetSocketAddress; 
8. import java.nio.ByteBuffer; 
9. import java.nio.channels.ClosedChannelException; 
10. import java.nio.channels.FileChannel; 
11. import java.nio.channels.SelectionKey; 
12. import java.nio.channels.Selector; 
13. import java.nio.channels.ServerSocketChannel; 
14. import java.nio.channels.SocketChannel; 
15. import java.util.Iterator; 
16. import java.util.logging.Level; 
17. import java.util.logging.Logger; 
18.  
19. public class MyServer4 { 
20.  
21.     private finalstatic Logger logger = Logger.getLogger(MyServer4.class.getName()); 
22.      
23.     public staticvoid main(String[] args) { 
24.         Selector selector = null; 
25.         ServerSocketChannel serverSocketChannel = null; 
26.          
27.         try { 
28.             // Selector for incoming time requests 
29.             selector = Selector.open(); 
30.  
31.             // Create a new server socket and set to non blocking mode 
32.             serverSocketChannel = ServerSocketChannel.open(); 
33.             serverSocketChannel.configureBlocking(false); 
34.              
35.             // Bind the server socket to the local host and port 
36.             serverSocketChannel.socket().setReuseAddress(true); 
37.             serverSocketChannel.socket().bind(new InetSocketAddress(10000)); 
38.              
39.             // Register accepts on the server socket with the selector. This 
40.             // step tells the selector that the socket wants to be put on the 
41.             // ready list when accept operations occur, so allowing multiplexed 
42.             // non-blocking I/O to take place. 
43.             serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT); 
44.      
45.             // Here's where everything happens. The select method will 
46.             // return when any operations registered above have occurred, the 
47.             // thread has been interrupted, etc. 
48.             while (selector.select() >0) { 
49.                 // Someone is ready for I/O, get the ready keys 
50.                 Iterator<SelectionKey> it = selector.selectedKeys().iterator(); 
51.      
52.                 // Walk through the ready keys collection and process date requests. 
53.                 while (it.hasNext()) { 
54.                     SelectionKey readyKey = it.next(); 
55.                     it.remove(); 
56.                      
57.                     // The key indexes into the selector so you 
58.                     // can retrieve the socket that's ready for I/O 
59.                     doit((ServerSocketChannel) readyKey.channel()); 
60.                 } 
61.             } 
62.         } catch (ClosedChannelException ex) { 
63.             logger.log(Level.SEVERE, null, ex); 
64.         } catch (IOException ex) { 
65.             logger.log(Level.SEVERE, null, ex); 
66.         } finally { 
67.             try { 
68.                 selector.close(); 
69.             } catch(Exception ex) {} 
70.             try { 
71.                 serverSocketChannel.close(); 
72.             } catch(Exception ex) {} 
73.         } 
74.     } 
75.  
76.     private staticvoid doit(final ServerSocketChannel serverSocketChannel)throws IOException { 
77.         SocketChannel socketChannel = null; 
78.         try { 
79.             socketChannel = serverSocketChannel.accept(); 
80.              
81.             receiveFile(socketChannel, new File("E:/test/server_receive.log")); 
82.             sendFile(socketChannel, new File("E:/test/server_send.log")); 
83.         } finally { 
84.             try { 
85.                 socketChannel.close(); 
86.             } catch(Exception ex) {} 
87.         } 
88.          
89.     } 
90.      
91.     private staticvoid receiveFile(SocketChannel socketChannel, File file)throws IOException { 
92.         FileOutputStream fos = null; 
93.         FileChannel channel = null; 
94.          
95.         try { 
96.             fos = new FileOutputStream(file); 
97.             channel = fos.getChannel(); 
98.             ByteBuffer buffer = ByteBuffer.allocateDirect(1024); 
99.  
100.             int size = 0; 
101.             while ((size = socketChannel.read(buffer)) != -1) { 
102.                 buffer.flip(); 
103.                 if (size >0) { 
104.                     buffer.limit(size); 
105.                     channel.write(buffer); 
106.                     buffer.clear(); 
107.                 } 
108.             } 
109.         } finally { 
110.             try { 
111.                 channel.close(); 
112.             } catch(Exception ex) {} 
113.             try { 
114.                 fos.close(); 
115.             } catch(Exception ex) {} 
116.         } 
117.     } 
118.  
119.     private staticvoid sendFile(SocketChannel socketChannel, File file)throws IOException { 
120.         FileInputStream fis = null; 
121.         FileChannel channel = null; 
122.         try { 
123.             fis = new FileInputStream(file); 
124.             channel = fis.getChannel(); 
125.             ByteBuffer buffer = ByteBuffer.allocateDirect(1024); 
126.             int size = 0; 
127.             while ((size = channel.read(buffer)) != -1) { 
128.                 buffer.rewind(); 
129.                 buffer.limit(size); 
130.                 socketChannel.write(buffer); 
131.                 buffer.clear(); 
132.             } 
133.             socketChannel.socket().shutdownOutput(); 
134.         } finally { 
135.             try { 
136.                 channel.close(); 
137.             } catch(Exception ex) {} 
138.             try { 
139.                 fis.close(); 
140.             } catch(Exception ex) {} 
141.         } 
142.     } 
143. } 

package com.googlecode.garbagecan.test.socket.nio;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.ClosedChannelException;import java.nio.channels.FileChannel;import java.nio.channels.SelectionKey;import java.nio.channels.Selector;import java.nio.channels.ServerSocketChannel;import java.nio.channels.SocketChannel;import java.util.Iterator;import java.util.logging.Level;import java.util.logging.Logger;public class MyServer4 {private final static Logger logger = Logger.getLogger(MyServer4.class.getName());public static void main(String[] args) {Selector selector = null;ServerSocketChannel serverSocketChannel = null;try {// Selector for incoming time requestsselector = Selector.open();// Create a new server socket and set to non blocking modeserverSocketChannel = ServerSocketChannel.open();serverSocketChannel.configureBlocking(false);// Bind the server socket to the local host and portserverSocketChannel.socket().setReuseAddress(true);serverSocketChannel.socket().bind(new InetSocketAddress(10000));// Register accepts on the server socket with the selector. This// step tells the selector that the socket wants to be put on the// ready list when accept operations occur, so allowing multiplexed// non-blocking I/O to take place.serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);// Here's where everything happens. The select method will// return when any operations registered above have occurred, the// thread has been interrupted, etc.while (selector.select() > 0) {// Someone is ready for I/O, get the ready keysIterator<SelectionKey> it = selector.selectedKeys().iterator();// Walk through the ready keys collection and process date requests.while (it.hasNext()) {SelectionKey readyKey = it.next();it.remove();// The key indexes into the selector so you// can retrieve the socket that's ready for I/Odoit((ServerSocketChannel) readyKey.channel());}}} catch (ClosedChannelException ex) {logger.log(Level.SEVERE, null, ex);} catch (IOException ex) {logger.log(Level.SEVERE, null, ex);} finally {try {selector.close();} catch(Exception ex) {}try {serverSocketChannel.close();} catch(Exception ex) {}}}private static void doit(final ServerSocketChannel serverSocketChannel) throws IOException {SocketChannel socketChannel = null;try {socketChannel = serverSocketChannel.accept();receiveFile(socketChannel, new File("E:/test/server_receive.log"));sendFile(socketChannel, new File("E:/test/server_send.log"));} finally {try {socketChannel.close();} catch(Exception ex) {}}}private static void receiveFile(SocketChannel socketChannel, File file) throws IOException {FileOutputStream fos = null;FileChannel channel = null;try {fos = new FileOutputStream(file);channel = fos.getChannel();ByteBuffer buffer = ByteBuffer.allocateDirect(1024);int size = 0;while ((size = socketChannel.read(buffer)) != -1) {buffer.flip();if (size > 0) {buffer.limit(size);channel.write(buffer);buffer.clear();}}} finally {try {channel.close();} catch(Exception ex) {}try {fos.close();} catch(Exception ex) {}}}private static void sendFile(SocketChannel socketChannel, File file) throws IOException {FileInputStream fis = null;FileChannel channel = null;try {fis = new FileInputStream(file);channel = fis.getChannel();ByteBuffer buffer = ByteBuffer.allocateDirect(1024);int size = 0;while ((size = channel.read(buffer)) != -1) {buffer.rewind();buffer.limit(size);socketChannel.write(buffer);buffer.clear();}socketChannel.socket().shutdownOutput();} finally {try {channel.close();} catch(Exception ex) {}try {fis.close();} catch(Exception ex) {}}}}

下面是Client程序代码，也主要关注sendFile和receiveFile方法

[java] view plaincopyprint?

1. package com.googlecode.garbagecan.test.socket.nio; 
2.  
3. import java.io.File; 
4. import java.io.FileInputStream; 
5. import java.io.FileOutputStream; 
6. import java.io.IOException; 
7. import java.net.InetSocketAddress; 
8. import java.net.SocketAddress; 
9. import java.nio.ByteBuffer; 
10. import java.nio.channels.FileChannel; 
11. import java.nio.channels.SocketChannel; 
12. import java.util.logging.Level; 
13. import java.util.logging.Logger; 
14.  
15. public class MyClient4 { 
16.  
17.     private finalstatic Logger logger = Logger.getLogger(MyClient4.class.getName()); 
18.      
19.     public staticvoid main(String[] args) throws Exception { 
20.         new Thread(new MyRunnable()).start(); 
21.     } 
22.      
23.     private staticfinal class MyRunnableimplements Runnable { 
24.         public void run() { 
25.             SocketChannel socketChannel = null; 
26.             try { 
27.                 socketChannel = SocketChannel.open(); 
28.                 SocketAddress socketAddress = new InetSocketAddress("localhost",10000); 
29.                 socketChannel.connect(socketAddress); 
30.  
31.                 sendFile(socketChannel, new File("E:/test/client_send.log")); 
32.                 receiveFile(socketChannel, new File("E:/test/client_receive.log")); 
33.             } catch (Exception ex) { 
34.                 logger.log(Level.SEVERE, null, ex); 
35.             } finally { 
36.                 try { 
37.                     socketChannel.close(); 
38.                 } catch(Exception ex) {} 
39.             } 
40.         } 
41.  
42.         private void sendFile(SocketChannel socketChannel, File file)throws IOException { 
43.             FileInputStream fis = null; 
44.             FileChannel channel = null; 
45.             try { 
46.                 fis = new FileInputStream(file); 
47.                 channel = fis.getChannel(); 
48.                 ByteBuffer buffer = ByteBuffer.allocateDirect(1024); 
49.                 int size =0; 
50.                 while ((size = channel.read(buffer)) != -1) { 
51.                     buffer.rewind(); 
52.                     buffer.limit(size); 
53.                     socketChannel.write(buffer); 
54.                     buffer.clear(); 
55.                 } 
56.                 socketChannel.socket().shutdownOutput(); 
57.             } finally { 
58.                 try { 
59.                     channel.close(); 
60.                 } catch(Exception ex) {} 
61.                 try { 
62.                     fis.close(); 
63.                 } catch(Exception ex) {} 
64.             } 
65.         } 
66.  
67.         private void receiveFile(SocketChannel socketChannel, File file)throws IOException { 
68.             FileOutputStream fos = null; 
69.             FileChannel channel = null; 
70.              
71.             try { 
72.                 fos = new FileOutputStream(file); 
73.                 channel = fos.getChannel(); 
74.                 ByteBuffer buffer = ByteBuffer.allocateDirect(1024); 
75.  
76.                 int size = 0; 
77.                 while ((size = socketChannel.read(buffer)) != -1) { 
78.                     buffer.flip(); 
79.                     if (size >0) { 
80.                         buffer.limit(size); 
81.                         channel.write(buffer); 
82.                         buffer.clear(); 
83.                     } 
84.                 } 
85.             } finally { 
86.                 try { 
87.                     channel.close(); 
88.                 } catch(Exception ex) {} 
89.                 try { 
90.                     fos.close(); 
91.                 } catch(Exception ex) {} 
92.             } 
93.         } 
94.     } 
95. } 

package com.googlecode.garbagecan.test.socket.nio;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.net.InetSocketAddress;import java.net.SocketAddress;import java.nio.ByteBuffer;import java.nio.channels.FileChannel;import java.nio.channels.SocketChannel;import java.util.logging.Level;import java.util.logging.Logger;public class MyClient4 {private final static Logger logger = Logger.getLogger(MyClient4.class.getName());public static void main(String[] args) throws Exception {new Thread(new MyRunnable()).start();}private static final class MyRunnable implements Runnable {public void run() {SocketChannel socketChannel = null;try {socketChannel = SocketChannel.open();SocketAddress socketAddress = new InetSocketAddress("localhost", 10000);socketChannel.connect(socketAddress);sendFile(socketChannel, new File("E:/test/client_send.log"));receiveFile(socketChannel, new File("E:/test/client_receive.log"));} catch (Exception ex) {logger.log(Level.SEVERE, null, ex);} finally {try {socketChannel.close();} catch(Exception ex) {}}}private void sendFile(SocketChannel socketChannel, File file) throws IOException {FileInputStream fis = null;FileChannel channel = null;try {fis = new FileInputStream(file);channel = fis.getChannel();ByteBuffer buffer = ByteBuffer.allocateDirect(1024);int size = 0;while ((size = channel.read(buffer)) != -1) {buffer.rewind();buffer.limit(size);socketChannel.write(buffer);buffer.clear();}socketChannel.socket().shutdownOutput();} finally {try {channel.close();} catch(Exception ex) {}try {fis.close();} catch(Exception ex) {}}}private void receiveFile(SocketChannel socketChannel, File file) throws IOException {FileOutputStream fos = null;FileChannel channel = null;try {fos = new FileOutputStream(file);channel = fos.getChannel();ByteBuffer buffer = ByteBuffer.allocateDirect(1024);int size = 0;while ((size = socketChannel.read(buffer)) != -1) {buffer.flip();if (size > 0) {buffer.limit(size);channel.write(buffer);buffer.clear();}}} finally {try {channel.close();} catch(Exception ex) {}try {fos.close();} catch(Exception ex) {}}}}}

首先运行MyServer4类启动监听，然后运行MyClient4类来向服务器发送文件以及接受服务器响应文件。运行完后，分别检查服务器和客户端接收到的文件。