package asynchronizedchannel;
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.security.MessageDigest;
import java.util.Iterator;
public class Server
{
/**
* 服务端通信范例程序主函数
*
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException
{
// Create the selector
final Selector selector = Selector.open();
final ServerSocketChannel server = ServerSocketChannel.open();
server.configureBlocking(false);
server.socket().bind(new InetSocketAddress("xx.xx.xx.xx", 5656), 5);
// Register both channels with selector
server.register(selector, SelectionKey.OP_ACCEPT);
new Thread(new Daemon(selector)).start();
}
}
class Daemon implements Runnable
{
private final Selector selector;
Daemon(Selector selector)
{
this.selector = selector;
}
public void run()
{
while (true) {
try {
// Wait for an event
selector.select();
// Get list of selection keys with pending events
Iterator<SelectionKey> it = selector.selectedKeys().iterator();
// Process each key
while (it.hasNext()) {
// Get the selection key
SelectionKey selKey = it.next();
// Remove it from the list to indicate that it is being processed
it.remove();
// Check if it's a connection request
if (selKey.isAcceptable()) {
// Get channel with connection request
ServerSocketChannel server = (ServerSocketChannel) selKey.channel();
// Accept the connection request.
// If serverSocketChannel is blocking, this method blocks.
// The returned channel is in blocking mode.
SocketChannel channel = server.accept();
// If serverSocketChannel is non-blocking, sChannel may be null
if (channel != null) {
// Use the socket channel to communicate with the client
new Thread(new ServerHandler(channel)).start();
} else {
System.out.println("---No Connection---");
// There were no pending connection requests; try again later.
// To be notified of connection requests,
}
}
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
}
class ServerHandler implements Runnable
{
private static final long timeout = 30 * 1000; // 设置超时时间为30秒
private static int counter = 0;
private final TcpChannel channel;
private final MessageDigest md;
ServerHandler(SocketChannel channel) throws Exception
{
this.channel = new TcpChannel(channel, System.currentTimeMillis() + timeout, SelectionKey.OP_READ);
md = MessageDigest.getInstance("md5");
}
public void run()
{
try {
while (true) {
work();
synchronized (ServerHandler.class) {
if ((++counter & 65535) == 0) {
System.out.println(counter);
}
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
channel.cleanup();
}
}
private void work() throws IOException
{ // 模拟工作流程
byte[] cache = new byte[256], reply = new byte[5];
read(cache, reply);
}
private void read(byte[] cache, byte[] reply) throws IOException
{ // 从套接字读入数据
channel.recv(ByteBuffer.wrap(cache));
md.reset();
md.update(cache, 0, 240);
byte[] md5 = md.digest(); // 使用前240字节产生MD5校验码
if (!ExtArrays.partialEquals(md5, 0, cache, 240, 16)) { // 与后16字节比较
reply[0] = '?';
System.out.println("MISMATCH!");
} else {
reply[0] = '.';
}
channel.send(ByteBuffer.wrap(reply)); // 返回接收结果
}
}
final class ExtArrays
{
private ExtArrays()
{
}
public static boolean partialEquals(byte[] a, int offset_a, byte[] b, int offset_b, int len)
{ // 字节数组的部分比较
if (a == null || b == null) {
return false;
}
if (offset_a + len > a.length || offset_b + len > b.length) {
return false;
}
for (int i = offset_a, j = offset_b, k = len; k > 0; i++, j++, k--) {
if (a[i] != b[j]) {
return false;
}
}
return true;
}
}
