SocketChannel 例子

cu_Cbear

SocketChannel 例子

这几天在看mina  
mina 基于socketChannel 和 DatagramChannel 建立的无阻塞链接。

所以就看了看socket channel 的使用方式，做一份备忘吧。
socketChannel 的使用方式

server端

1. 
   
2. package com.jimmy.nio;
   
3. 
   
4. import java.io.IOException;
   
5. import java.net.InetSocketAddress;
   
6. import java.net.SocketAddress;
   
7. import java.nio.ByteBuffer;
   
8. import java.nio.ByteOrder;
   
9. import java.nio.channels.ServerSocketChannel;
   
10. import java.nio.channels.SocketChannel;
    
11. import java.util.Date;
    
12. 
    
13. public class TestServerSocketChannel {
    
14.     public static void main(String[] args) throws IOException {
    
15.         int port=37;
    
16. 
    
17.         ByteBuffer in=ByteBuffer.allocate(4);
    
18.         ByteBuffer out=ByteBuffer.allocate(8);
    
19.         
    
20.         //设置绑定端口
    
21.         SocketAddress address=new InetSocketAddress(port);
    
22. 
    
23.         //Opens a server-socket channel.
    
24.         ServerSocketChannel serverSocketChannel=ServerSocketChannel.open();
    
25. 
    
26.         //Binds the ServerSocket to a specific address (IP address and port number).
    
27.          serverSocketChannel.socket().bind(address);
    
28. 
    
29.         System.err.println("bound to " + address);
    
30.         
    
31.         //Accepts a connection made to this channel's socket
    
32.         SocketChannel channel=serverSocketChannel.accept();
    
33.         if(channel == null) {
    
34.             return;
    
35.         }
    
36.         //clear byte buffer
    
37.         in.clear();
    
38.         //read byte to "in" buffer
    
39.         channel.read(in);
    
40.         //Flips this buffer
    
41.         in.flip();
    
42.         int a=in.getInt();
    
43.         System.out.println("a:" + a);
    
44. 
    
45.         //get remote socket address
    
46.         SocketAddress client=channel.socket().getRemoteSocketAddress();
    
47.         System.err.println(client);
    
48.         long secondsSince1970=System.currentTimeMillis();
    
49. 
    
50.         //clear "out" byte buffer
    
51.         out.clear();
    
52.         //put currentTimeMillis value into "out" byte buffer
    
53.         out.putLong(secondsSince1970);
    
54.         //Flips this buffer
    
55.         out.flip();
    
56. 
    
57.         //Writes a sequence of bytes to this channel from the given buffer
    
58.         //write data from position to limit of buffer
    
59.         //so before write ,buffer need call flip method
    
60.         channel.write(out);
    
61. 
    
62.         channel.close();
    
63. 
    
64.         serverSocketChannel.close();
    
65.     }
    
66. }

复制代码

client 端

1. package com.jimmy.nio;
   
2. 
   
3. import java.io.IOException;
   
4. import java.net.InetSocketAddress;
   
5. import java.net.SocketAddress;
   
6. import java.nio.ByteBuffer;
   
7. import java.nio.channels.SocketChannel;
   
8. import java.util.Date;
   
9. 
   
10. public class TestClientSocketChannel {
    
11. 
    
12.     public static void main(String[] args) throws IOException {
    
13.         int port=37;
    
14.         SocketChannel channel=SocketChannel.open();
    
15.         SocketAddress server=new InetSocketAddress("192.168.1.79", port);
    
16.         channel.connect(server);
    
17. 
    
18.         ByteBuffer buffer=ByteBuffer.allocate(4);
    
19.         ByteBuffer readBuffer=ByteBuffer.allocate(8);
    
20.         
    
21.         // send a byte of data to the server
    
22.         buffer.putInt(100);
    
23.         buffer.flip();
    
24.         channel.write(buffer);
    
25. 
    
26.         // get the buffer ready to receive data
    
27.         channel.read(readBuffer);
    
28.         readBuffer.flip();
    
29. 
    
30.         // convert seconds since 1900 to a java.util.Date
    
31.         long currentTimeMillis=readBuffer.getLong();
    
32. 
    
33.         Date time=new Date(currentTimeMillis);
    
34. 
    
35.         System.out.println(time);
    
36. 
    
37.         channel.close();
    
38.     }
    
39. }

复制代码

socket channel 操作的对象是ByteBuffer
在read的时候如果byte length 超过了 byteBuffer分配的空间 会抛出java.nio.BufferUnderflowException 异常。
在设置 bytebuffer 空间的时候建议设置大一些。

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