Java Socket编程实例（四）

Java Socket编程实例（四）

一、回传协议接口和TCP方式实现：

1.接口：

import java.nio.channels.SelectionKey;

import java.io.IOException;

public interface EchoProtocol {

void handleAccept(SelectionKey key) throws IOException;

void handleRead(SelectionKey key) throws IOException;

void handleWrite(SelectionKey key) throws IOException;

}

2.实现：

import java.nio.channels.*;

import java.nio.ByteBuffer;

import java.io.IOException;

public class TCPEchoSelectorProtocol implements EchoProtocol{

private int bufSize; // Size of I/O buffer

public EchoSelectorProtocol(int bufSize) {

this.bufSize = bufSize;

}

public void handleAccept(SelectionKey key) throws IOException {

SocketChannel clntChan = ((ServerSocketChannel) key.channel()).accept();

clntChan.configureBlocking(false); // Must be nonblocking to register

// Register the selector with new channel for read and attach byte buffer

clntChan.register(key.selector(), SelectionKey.OP_READ, ByteBuffer.allocate(bufSize));

}

public void handleRead(SelectionKey key) throws IOException {

// Client socket channel has pending data

SocketChannel clntChan = (SocketChannel) key.channel();

ByteBuffer buf = (ByteBuffer) key.attachment();

long bytesRead = clntChan.read(buf);

if (bytesRead == -1) { // Did the other end close?

clntChan.close();

} else if (bytesRead > 0) {

// Indicate via key that reading/writing are both of interest now.

key.interestOps(SelectionKey.OP_READ | SelectionKey.OP_WRITE);

}

}

public void handleWrite(SelectionKey key) throws IOException {

/*

* Channel is available for writing, and key is valid (i.e., client channel

* not closed).

*/

// Retrieve data read earlier

ByteBuffer buf = (ByteBuffer) key.attachment();

buf.flip(); // Prepare buffer for writing

SocketChannel clntChan = (SocketChannel) key.channel();

clntChan.write(buf);

if (!buf.hasRemaining()) { // Buffer completely written?

//Nothing NIDCuqFmGleft, so no longer interested in writes

key.interestOps(SelectionKey.OP_READ);

}

buf.compact(); // Make room for more data to be read in

}

}

二、NIO TCP客户端：

import java.net.InetSocketAddress;

import java.net.SocketException;

import java.nio.ByteBuffer;

import java.nio.channels.SocketChannel;

public class TCPEchoClientNonblocking {

public static void main(String args[]) throws Exception {

String server = "127.0.0.1"; // Server name or IP address

// Convert input String to bytes using the default charset

byte[] argument = "0123456789abcdefghijklmnopqrstuvwxyz".getBytes();

int servPort = 5500;

// Create channel and set to nonblocking

SocketChannel clntChan = SocketChannel.open();

clntChan.configureBlocking(false);

// Initiate connection to server and repeatedly poll until complete

if (!clntChan.connect(new InetSockeNIDCuqFmGtAddress(server, servPort))) {

while (!clntChan.finishConnect()) {

System.out.print("."); // Do something else

}

}

ByteBuffer writeBuf = ByteBuffer.wrap(argument);

ByteBuffer readBuf = ByteBuffer.allocate(argument.length);

int totalBytesRcvd = 0; // Total bytes received so far

int bytesRcvd; // Bytes received in last read

while (totalBytesRcvd < argument.length) {

if (writeBuf.hasRemaining()) {

NIDCuqFmG clntChan.write(writeBuf);

}

if ((bytesRcvd = clntChan.read(readBuf)) == -1) {

throw new SocketException("Connection closed prematurely");

}

totalBytesRcvd += bytesRcvd;

System.out.print("."); // Do something else

}

System.out.println("Received: " + // convert to String per default charset

new String(readBuf.array(), 0, totalBytesRcvd).length());

clntChan.close();

}

}

三、NIO TCP服务端：

import java.io.IOException;

import java.net.InetSocketAddress;

import java.nio.channels.*;

import java.util.Iterator;

public class TCPServerSelector {

private static final int BUFSIZE = 256; // Buffer size (bytes)

private static final int TIMEOUT = 3000; // Wait timeout (milliseconds)

public static void main(String[] args) throws IOException {

int[] ports = {5500};

// Create a selector to multiplex listening sockets and connections

Selector selector = Selector.open();

// Create listening socket channel for each port and register selector

for (int port : ports) {

ServerSocketChannel listnChannel = ServerSocketChannel.open();

listnChannel.socket().bind(new InetSocketAddress(port));

listnChannel.configureBlocking(false); // must be nonblocking to register

// Register selector with channel. The returned key is ignored

listnChannel.register(selector, SelectionKey.OP_ACCEPT);

}

// Create a handler that will implement the protocol

TCPProtocol protocol = new TCPEchoSelectorProtocol(BUFSIZE);

while (true) { // Run forever, processing available I/O operations

// Wait for sohttp://me channel to be ready (or timeout)

if (selector.select(TIMEOUT) == 0) { // returns # of ready chans

System.out.print(".");

continue;

}

// Get iterator on set of keys with I/O to process

Iterator keyIter = selector.selectedKeys().iterator();

while (keyIter.hasNext()) {

SelectionKey key = keyIter.next(); // Key is bit mask

// Server socket channel has pending connection requests?

if (key.isAcceptable()) {

System.out.println("----accept-----");

protocol.handleAccept(key);

}

// Client socket channel has pending data?

if (key.isReadable()) {

System.out.println("----read-----");

protocol.handleRead(key);

}

// Client socket channel is available for writing and

// key is valid (i.e., channel not closed)?

if (key.isValid() && key.isWritable()) {

System.out.println("----write-----");

protocol.handleWrite(key);

}

keyIter.remove(); // remove from set of selected keys

}

}

}

}

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。