java7 nio 例子

/**
*
*/
package Test;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

/**
*
* @author Administrator
* @version
*/

public class NBTest {

/** Creates new NBTest */
public NBTest() {
}

public void startServer() throws Exception {
int channels = 0;
int nKeys = 0;
int currentSelector = 0;

// 使用Selector
Selector selector = Selector.open();

// 建立Channel 并绑定到9000端口
ServerSocketChannel ssc = ServerSocketChannel.open();
InetSocketAddress address = new InetSocketAddress(
InetAddress.getLocalHost(), 9000);
ssc.socket().bind(address);

// 使设定non-blocking的方式。
ssc.configureBlocking(false);

// 向Selector注册Channel及我们有兴趣的事件
SelectionKey s = ssc.register(selector, SelectionKey.OP_ACCEPT);
printKeyInfo(s);

while (true) // 不断的轮询
{
debug("NBTest: Starting select");

// Selector通过select方法通知我们我们感兴趣的事件发生了。
nKeys = selector.select();
// 如果有我们注册的事情发生了，它的传回值就会大于0
if (nKeys > 0) {
debug("NBTest: Number of keys after select operation: " + nKeys);

// Selector传回一组SelectionKeys
// 我们从这些key中的channel()方法中取得我们刚刚注册的channel。
Set selectedKeys = selector.selectedKeys();
Iterator i = selectedKeys.iterator();
while (i.hasNext()) {
s = (SelectionKey) i.next();
printKeyInfo(s);
debug("NBTest: Nr Keys in selector: "
+ selector.keys().size());

// 一个key被处理完成后，就都被从就绪关键字（ready keys）列表中除去
i.remove();
if (s.isAcceptable()) {
// 从channel()中取得我们刚刚注册的channel。
Socket socket = ((ServerSocketChannel) s.channel())
.accept().socket();
SocketChannel sc = socket.getChannel();

sc.configureBlocking(false);
sc.register(selector, SelectionKey.OP_READ
| SelectionKey.OP_WRITE);
System.out.println(++channels);
} else {
debug("NBTest: Channel not acceptable");
}
}
} else {
debug("NBTest: Select finished without any keys.");
}

}

}

private static void debug(String s) {
System.out.println(s);
}

private static void printKeyInfo(SelectionKey sk) {
String s = new String();

s = "Att: " + (sk.attachment() == null ? "no" : "yes");
s += ", Read: " + sk.isReadable();
s += ", Acpt: " + sk.isAcceptable();
s += ", Cnct: " + sk.isConnectable();
s += ", Wrt: " + sk.isWritable();
s += ", Valid: " + sk.isValid();
s += ", Ops: " + sk.interestOps();
debug(s);
}

/**
* @param args
*            the command line arguments
*/
public static void main(String args[]) {
NBTest nbTest = new NBTest();
try {
nbTest.startServer();
} catch (Exception e) {
e.printStackTrace();
}
}

}