Netty权威指南-NIO实现TimeServer服务器端源代码

package com.jianweigang.NIO;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Date;
import java.util.Iterator;
import java.util.Set;

public class TimeServer {
private static int DEFAULT_PORT = 8080;
public static void main(String[] args) throws IOException {
int port = 8080;
if(args != null && args.length > 0 ) {
try {
port = Integer.valueOf(args[0]);
}catch(NumberFormatException e){
//如果没有传，那我们就使用默认的端口
port = DEFAULT_PORT;
}
}
//创建一个多路复用器
MultiplexerTimeServer timeServer = new MultiplexerTimeServer(port);
//单独启动一个线程
new Thread(timeServer, "NIO-MultiplexerTimerServer-001").start();
}
}

class MultiplexerTimeServer implements Runnable {

private Selector selector;
private ServerSocketChannel servChannel;
private volatile boolean stop;

public MultiplexerTimeServer(int port) {
try{
selector = Selector.open();
servChannel = ServerSocketChannel.open();
servChannel.configureBlocking(false);
servChannel.socket().bind(new InetSocketAddress(port),1024);
servChannel.register(selector, SelectionKey.OP_CONNECT);
this.stop = false;
System.out.println("The Time Server is start in port : " + port);
}catch(IOException e){
e.printStackTrace();
System.exit(1);
}
}
public void stop() {
this.stop = true;
}

public void run() {
while(!stop) {
try {
//wait until 1000 millisecond
selector.select(1000);
Set<SelectionKey> selectionKeys = selector.selectedKeys();
Iterator<SelectionKey> it = selectionKeys.iterator();
SelectionKey key = null;
while(it.hasNext()) {
key = it.next();
try{
handleInput(key);
}catch(Exception e) {

}
if(key != null) {
key.cancel();
if(key.channel() != null) {
key.channel().close();
}
}
}
}catch(Exception e) {
e.printStackTrace();
}
}
//多路复用器关闭以后，所有注册在上面的Channel和Pipe等资源都会自动去注册并关闭，所以不需要重复释放资源
if(selector != null) {
try{
selector.close();
}catch(IOException e){
e.printStackTrace();
}
}
}

//处理事件响应
private void handleInput(SelectionKey key) throws Exception {
if(key.isValid()) {
if(key.isAcceptable()) {
ServerSocketChannel ssc = (ServerSocketChannel)key.channel();
SocketChannel sc = ssc.accept();
sc.configureBlocking(false);
sc.register(selector, SelectionKey.OP_READ);
}
if(key.isReadable()) {
SocketChannel sc = (SocketChannel)key.channel();
ByteBuffer readBuffer = ByteBuffer.allocate(1024);
int readBytes = sc.read(readBuffer);
if(readBytes > 0) {
byte[] bytes = new byte[readBuffer.remaining()];
readBuffer.get(bytes);
String body = new String(bytes, "UTF-8");
System.out.println("The time Server receive order:" + body);
String response = "success get message at:" + new Date(System.currentTimeMillis()).toString();
doWrite(sc, response);
} else {
key.cancel();
sc.close();
}
}
}
}

//在成功接受客户端的请求消息以后，同时给客户端返回一条成功的信息
private void doWrite(SocketChannel sc, String response) throws Exception {
if(response != null && response.length() > 0) {
byte[] bytes = response.getBytes();
ByteBuffer writeBuffer  = ByteBuffer.allocate(bytes.length);
writeBuffer.put(bytes);
writeBuffer.flip();
sc.write(writeBuffer);
}
}
}