Java IO多路复用技术简介
/**
* @author qifuguang
* @date 15-2-4 下午2:07
*/
public class TimeServerMain {
public static void main(String[] args) throws Exception {
// 启动时间服务器
new Thread(new SelectorTimeServer()).start();
}
}
/**
* @author qifuguang
* @date 15-2-4 下午2:09
*/
public class TimeClientMain {
public static void main(String[] args) throws Exception {
// 创建100个客户端连接到服务器
for (int i = 0; i < 100; i++) {
new Thread(new SelectorTimeClient(i + 1)).start();
}
}
}
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.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;
/**
* @author qifuguang
* @date 15-2-4 下午1:21
*/
public class SelectorTimeServer implements Runnable {
private static final String TIME_ORDER = "Query Time";
private Selector selector;
private ServerSocketChannel serverChannel;
private volatile boolean stop = false;
/**
* 创建Selector, 创建ServerSocketChannel,并设置为非阻塞模式, 注册到selector.
*
* @throws Exception
*/
public SelectorTimeServer() throws Exception {
selector = Selector.open();
serverChannel = ServerSocketChannel.open();
serverChannel.socket().bind(new InetSocketAddress(8080));
serverChannel.configureBlocking(false);
serverChannel.register(selector, SelectionKey.OP_ACCEPT);
}
/**
* 轮询监听selector.
*/
@Override
public void run() {
try {
System.out.println("时间服务器启动！");
while (!stop) {
selector.select(1000);
Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
while (iterator.hasNext()) {
SelectionKey key = iterator.next();
iterator.remove();
handleKey(key);
}
}
if (selector != null) {
selector.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 处理每一种selector感兴趣的事件.
*
* @param key 轮询监听得到的SelectionKey.
*/
private void handleKey(SelectionKey key) {
try {
if (key.isValid()) { // 如果连接成功
if (key.isAcceptable()) { // 监听到有新客户端连接
SocketChannel accept = ((ServerSocketChannel) key.channel()).accept(); // 建立与客户端的连接
accept.configureBlocking(false); // 设置该连接为非阻塞模式
accept.register(selector, SelectionKey.OP_READ); // 将该连接注册到selector
System.out.println("发现有新客户端连接...");
}
if (key.isReadable()) { // 监听到有客户端发送请求
SocketChannel channel = (SocketChannel) key.channel();
// 读取客户端发来的请求
ByteBuffer buff = ByteBuffer.allocate(1024);
int size = channel.read(buff);
if (size > 0) {
byte[] b = new byte[size];
buff.flip();
buff.get(b);
String order = new String(b, "UTF-8");
System.out.println("收到客户端命令：" + order);
String content = "";
if (order.equalsIgnoreCase(TIME_ORDER)) {
content = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
} else {
content = "命令错误";
}
// 根据客户端发来的请求做出相应的动作,并将处理结果返回给客户端
doWrite(channel, content);
} else if (size < 0) {
channel.close();
key.cancel();
} else {
;
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}