使用java nio socket时，“已建立的连接被主机中的软件中止” [英] 'An established connection was aborted by the software in your host machine' when using java nio socket
本文介绍了使用java nio socket时，“已建立的连接被主机中的软件中止”的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我使用java nio 套接字开发了一个java服务器。这是我的应用程序的代码：
I had developed an java server using java nio sockets. It is the code of my application:
public class EchoServer {
static final org.apache.log4j.Logger logger = org.apache.log4j.Logger.getLogger(Main.class);
private static final int BUFFER_SIZE = 1024;
private final static int DEFAULT_PORT = 4664;
private InetAddress hostAddress = null;
private int port;
private String ipAddress = "my ip";
private Selector selector;
// The buffer into which we'll read data when it's available
private ByteBuffer readBuffer = ByteBuffer.allocate(BUFFER_SIZE);
int timestamp = 1;
HashMap<Integer, String> connectedClients = new HashMap<Integer, String>();
HashMap<String, Integer> clientIds= new HashMap<String,Integer>();
HashMap<String, String> messageToClients = new HashMap<String, String>();
public EchoServer() {
this(DEFAULT_PORT);
}
public EchoServer(int port) {
try{
this.port = port;
hostAddress = InetAddress.getByName(ipAddress);
selector = initSelector();
loop();
}catch(Exception ex){
logger.error("Exception Accoured:",ex);
}
}
private Selector initSelector() {
try{
Selector socketSelector = SelectorProvider.provider().openSelector();
ServerSocketChannel serverChannel = ServerSocketChannel.open();
serverChannel.configureBlocking(false);
InetSocketAddress isa = new InetSocketAddress(hostAddress, port);
serverChannel.socket().bind(isa);
serverChannel.register(socketSelector, SelectionKey.OP_ACCEPT);
return socketSelector;
}catch(Exception ex){
logger.error("Exception Accoured:",ex);
return null;
}
}
private void loop() {
while (true) {
try {
// Do defined operations for clients
// ------------------------------
selector.select();
Iterator<SelectionKey> selectedKeys = selector.selectedKeys()
.iterator();
while (selectedKeys.hasNext()) {
SelectionKey key = selectedKeys.next();
selectedKeys.remove();
if (!key.isValid()) {
logger.warn(key.hashCode() + "- is invalid");
continue;
}
// Check what event is available and deal with it
if (key.isAcceptable()) {
accept(key);
} else if (key.isReadable()) {
read(key);
} else if (key.isWritable()) {
write(key);
}
}
// Fetch List from server
// -----------------------------------------
try {
ResultSet resultset = DataBase.getInstance()
.getQueryResult();
boolean flag = false;
while (resultset.next()) {
String mobileNumber = resultset.getString("MobileNo");
String message = resultset.getInt("IsMessage") + ","
+ resultset.getInt("IsDeliver") + ","
+ resultset.getInt("IsGroup") + ","
+ resultset.getInt("IsSeen");
messageToClients.put(mobileNumber, message);
}
} catch (Exception ex) {
//ex.printStackTrace();
logger.error("Exception Accoured:",ex);
}
// Wait for 1 second
// -----------------------------------------------
Thread.sleep(1000);
timestamp++;
} catch (Exception e) {
e.printStackTrace();
System.exit(1);
}
}
}
private void accept(SelectionKey key) {
try{
// Initialize the connection ------------------------------------------
ServerSocketChannel serverSocketChannel = (ServerSocketChannel) key
.channel();
SocketChannel socketChannel = serverSocketChannel.accept();
socketChannel.configureBlocking(false);
socketChannel.setOption(StandardSocketOptions.SO_KEEPALIVE, true);
socketChannel.setOption(StandardSocketOptions.TCP_NODELAY, true);
logger.info("New client accepted");
// Fire read for reading phone number --------------------------------
socketChannel.register(selector, SelectionKey.OP_READ);
}catch(Exception ex){
logger.error("Exception Accoured:",ex);
}
}
private void read(SelectionKey key) {
try{
// Initialize Socket -----------------------------------------------------
SocketChannel socketChannel = (SocketChannel) key.channel();
// Reading Client Number -------------------------------------------------
readBuffer.clear();
int numRead;
try {
numRead = socketChannel.read(readBuffer);
} catch (IOException e) {
logger.error("Forceful shutdown");
key.cancel();
return;
}
// read was not successful
if (numRead == -1) {
logger.error("Graceful shutdown");
key.cancel();
return;
}
// read was successful and now we can write it to String
readBuffer.flip();
byte[] bytes = new byte[readBuffer.limit()];
readBuffer.get(bytes);
String number = new String(bytes);
number = number.replace("\r\n", "");
number = number.trim();
// Update Connect Clients Status -----------------------------------------
Integer clientId=clientIds.get(number);
if ( clientId == null) {
connectedClients.put(key.hashCode(), number);
clientIds.put(number, key.hashCode());
logger.error(number + "- (" + key.hashCode() + ") has Connected");
}else{
connectedClients.remove(clientId);
connectedClients.put(key.hashCode(), number);
clientIds.put(number, key.hashCode());
logger.error(number + "- (" + key.hashCode() + ") REconnected");
}
//System.err.println("All clients number are:" + connectedClients.size());
logger.error("All clients number are:" + connectedClients.size());
// Fire Write Operations -------------------------------------------------
socketChannel.register(selector, SelectionKey.OP_WRITE);
}catch(Exception ex){
//ex.printStackTrace();
logger.error("Exception Accoured:",ex);
}
}
private void write(SelectionKey key) {
try {
//Check channel still alive ----------------------------------------------
String clientNumber = connectedClients.get(key.hashCode());
if(clientNumber == null){
key.cancel();
return;
}
// Get Channel -----------------------------------------------------------
SocketChannel socketChannel = (SocketChannel) key.channel();
// Send Message if client number have new message ------------------------
if (messageToClients.get(clientNumber) != null) {
logger.info(clientNumber + "-" + key.hashCode()
+ "- Sent write message");
String timeStamp = String.valueOf(timestamp);
String message = messageToClients.get(clientNumber);
ByteBuffer dummyResponse = ByteBuffer.wrap((message + "\r\n").getBytes("UTF-8"));
socketChannel.write(dummyResponse);
messageToClients.remove(clientNumber);
}
// Fire new write state --------------------------------------------------
socketChannel.register(selector, SelectionKey.OP_WRITE);
} catch (IOException iox) {
logger.error("Exception Accoured:",iox);
String number = connectedClients.get(key.hashCode());
clientIds.remove(number);
connectedClients.remove(key.hashCode());
key.cancel();
} catch(Exception ex){
logger.error("Exception Accoured:",ex);
}
}
}
当我使用2-3个客户端进行测试时，它工作正常，但是当我开始使用大约100-300客户端进行测试时，我多次在异常中进行了测试（实际上它正在<$ c上发生） $ c> write（）方法和行 socketChannel.write（dummyResponse）; ：
When I am testing with 2-3 clients it is working fine but when I start testing it with about 100-300 client I recived below exception at several times(Actually it is happeingin on write() method and line socketChannel.write(dummyResponse);:
java.io.IOException: An established connection was aborted by the software in your host machine
at sun.nio.ch.SocketDispatcher.write0(Native Method)
at sun.nio.ch.SocketDispatcher.write(Unknown Source)
at sun.nio.ch.IOUtil.writeFromNativeBuffer(Unknown Source)
at sun.nio.ch.IOUtil.write(Unknown Source)
at sun.nio.ch.SocketChannelImpl.write(Unknown Source)
at net.behboodi.testserver.EchoServer.write(EchoServer.java:274)
at net.behboodi.testserver.EchoServer.loop(EchoServer.java:106)
at net.behboodi.testserver.EchoServer.<init>(EchoServer.java:56)
at net.behboodi.testserver.EchoServer.<init>(EchoServer.java:47)
at net.behboodi.testserver.Main.main(Main.java:44)
然后我无法从服务器接收消息。
and then I can not receive messages from the server.
推荐答案
当你收到流结束时（ read（）返回 - 1）您没有关闭频道，因此您正在泄露频道。您需要关闭频道，并注意这样做会自动取消该密钥。仅仅取消密钥是不够的。取消密钥时相同，因为 clientNumber == null 或者你得到 IOException 。
When you get end of stream (read() returns -1) you aren't closing the channel, so you're leaking channels. You need to close the channel, and note that doing so will automatically cancel the key. Just cancelling the key by itself is not sufficient. Same when you cancel the key because clientNumber == null or you get an IOException.
注意你不应该注册 OP_WRITE 除非你刚从收到零写（）调用，如果没有得到零，你应该取消注册。
NB you shouldn't register OP_WRITE unless you have just received zero from a write() call, and you should deregister it whenever you don't get that zero.
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