我已经使用 java 7 nio2 编写了一个异步套接字服务器。
这是服务器的狙击手。
public class AsyncJava7Server implements Runnable, CounterProtocol, CounterServer{
private int port = 0;
private AsynchronousChannelGroup group;
public AsyncJava7Server(int port) throws IOException, InterruptedException, ExecutionException {
this.port = port;
}
public void run() {
try {
String localhostname = java.net.InetAddress.getLocalHost().getHostName();
group = AsynchronousChannelGroup.withThreadPool(
Executors.newCachedThreadPool(new NamedThreadFactory("Channel_Group_Thread")));
// open a server channel and bind to a free address, then accept a connection
final AsynchronousServerSocketChannel asyncServerSocketChannel =
AsynchronousServerSocketChannel.open(group).bind(
new InetSocketAddress(localhostname, port));
asyncServerSocketChannel.accept(null,
new CompletionHandler <AsynchronousSocketChannel, Object>() {
@Override
public void completed(final AsynchronousSocketChannel asyncSocketChannel,
Object attachment) {
// Invoke simple handle accept code - only takes about 10 milliseconds.
handleAccept(asyncSocketChannel);
asyncServerSocketChannel.accept(null, this);
}
@Override
public void failed(Throwable exc, Object attachment) {
System.out.println("***********" + exc + " statement=" + attachment);
}
});
这是尝试连接的客户端代码片段...
public class AsyncJava7Client implements CounterProtocol, CounterClientBridge {
AsynchronousSocketChannel asyncSocketChannel;
private String serverName= null;
private int port;
private String clientName;
public AsyncJava7Client(String clientName, String serverName, int port) throws IOException {
this.clientName = clientName;
this.serverName = serverName;
this.port = port;
}
private void connectToServer() {
Future<Void> connectFuture = null;
try {
log("Opening client async channel...");
asyncSocketChannel = AsynchronousSocketChannel.open();
// Connecting to server
connectFuture = asyncSocketChannel.connect(new InetSocketAddress("Alex-PC", 9999));
} catch (Exception ex) {
ex.printStackTrace();
throw new RuntimeException(ex);
}
// open a new socket channel and connect to the server
long beginTime = 0;
try {
// You have two seconds to connect. This will throw exception if server is not there.
beginTime = System.currentTimeMillis();
Void connectVoid = connectFuture.get(15, TimeUnit.SECONDS);
} catch (Exception ex) {
//EXCEPTIONS THROWN HERE AFTER ABOUT 150 CLIENTS
long endTime = System.currentTimeMillis();
long timeTaken = endTime - beginTime;
log("************* TIME TAKEN=" + timeTaken);
ex.printStackTrace();
throw new RuntimeException(ex);
}
}
我有一个测试可以触发客户。
@Test
public void testManyClientsAtSametime() throws Exception {
int clientsize = 150;
ScheduledThreadPoolExecutor executor =
(ScheduledThreadPoolExecutor) Executors.newScheduledThreadPool(clientsize + 1,
new NamedThreadFactory("Test_Thread"));
AsyncJava7Server asyncJava7Server = startServer();
List<AsyncJava7Client> clients = new ArrayList<AsyncJava7Client>();
List<Future<String>> results = new ArrayList<Future<String>>();
for (int i = 0; i < clientsize; i++) {
// Now start a client
final AsyncJava7Client client =
new AsyncJava7Client("client" + i, InetAddress.getLocalHost().getHostName(), 9999);
clients.add(client);
}
long beginTime = System.currentTimeMillis();
Random random = new Random();
for (final AsyncJava7Client client: clients) {
Callable<String> callable = new Callable<String>() {
public String call() {
...
... invoke APIs to connect client to server
...
return counterValue;
}
};
long delay = random.nextLong() % 10000; // somewhere between 0 and 10 seconds.
Future<String> startClientFuture = executor.schedule(callable, delay, TimeUnit.MILLISECONDS);
results.add(startClientFuture);
}
它对大约 100 个客户非常有效。在大约 140+ 时，我在客户端中收到大量异常 - 当它尝试连接时。异常是：java.util.concurrent.ExecutionException: java.io.IOException: 远程计算机拒绝网络连接。
我的测试是在一台运行 Windows 7 的笔记本电脑上进行的。当它爆炸时，我检查 TCP 连接，那里大约有 500 到 600 个连接——没关系。因为我有可以处理 4,000 个 TCP 连接的类似 JDK 1.0 java.net 套接字程序。
在服务器中没有例外或任何狡猾的东西。
所以我不知道这里可能出了什么问题。有任何想法吗？