Java Socket編程實例（四）- NIO TCP理論。本站提示廣大學習愛好者：（Java Socket編程實例（四）- NIO TCP理論）文章只能為提供參考，不一定能成為您想要的結果。以下是Java Socket編程實例（四）- NIO TCP理論正文
1、回傳協定接口和TCP方法完成：
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.完成：
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 left, so no longer interested in writes
key.interestOps(SelectionKey.OP_READ);
}
buf.compact(); // Make room for more data to be read in
}
}
2、NIO TCP客戶端：
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 InetSocketAddress(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()) {
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();
}
}
3、NIO TCP辦事端：
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 some 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<SelectionKey> 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
}
}
}
}
以上就是本文的全體內容，檢查更多Java的語法，年夜家可以存眷：《Thinking in Java 中文手冊》、《JDK 1.7 參考手冊官方英文版》、《JDK 1.6 API java 中文參考手冊》、《JDK 1.5 API java 中文參考手冊》，也願望年夜家多多支撐。
