我正在使用 Java 实现服务器/客户端系统。服务器侦听来自客户端的传入连接，在客户端连接后，服务器创建一个新套接字并将其传递给仅用于接收数据的新线程：
while (true){
clientSocket=serverSocket.accept();
new ClientReceiver(clientSocket,this.clientsManager).start();
}
clientReceiver 类如下：
public class ClientReceiver extends Thread {
private Socket clientSocket=null;
private Client client=null;
private ClientsManager clientsManager;
private ClientActionParser clientActionParser=new ClientActionParser();
ClientHandlerState clientHandlerState;
PrintWriter outputStream=null;
BufferedReader inputStream=null;
public ClientReceiver(Socket clientSocket, ClientsManager clientsManager){
this.clientSocket=clientSocket;
this.clientsManager=clientsManager;
this.setClientHandlerState(ClientHandlerState.Connected);
}
public void run(){
String actionString;
try{
//define output and input stream to client
outputStream =new PrintWriter(clientSocket.getOutputStream(),true);
inputStream = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
//while client is connected read input to actionString
while((actionString=inputStream.readLine()) != null){
AbstractClientAction clientAction= this.clientActionParser.parse(actionString);
if(this.getClientHandlerState()==ClientHandlerState.Connected){
if(clientAction instanceof ClientLoginAction){
ClientLoginAction clientLoginAction=(ClientLoginAction) clientAction;
if(this.authenticate(clientLoginAction)){
}
else{
throw new AuthenticationException();
}
}
else{
throw new AuthenticationException();
}
}
}
if(this.getClientHandlerState()==ClientHandlerState.Authorized){
//receive other client actions: transfer barge ....
}
try {
Thread.sleep(400);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
catch(IOException e){
}
catch (AuthenticationException e) {
// TODO: handle exception
}
//clean up the resources
try{
outputStream.close();
inputStream.close();
clientSocket.close();
}
catch(Exception e){
}
}
private boolean authenticate(ClientLoginAction clientLoginAction){
//perform authentication. If authentication successful:
this.client=this.clientsManager.authenticateClient(clientLoginAction.getUsername(), clientLoginAction.getPassword());
if(this.client==null){
return false;
}
else{
ClientSender clientSender=new ClientSender(this.outputStream, this.client);
this.clientsManager.addClientSender(clientSender);
this.setClientHandlerState(ClientHandlerState.Authorized);
clientSender.start();
return true;
}
}
public ClientHandlerState getClientHandlerState(){
return this.clientHandlerState;
}
public void setClientHandlerState(ClientHandlerState clientHandlerState){
this.clientHandlerState=clientHandlerState;
}
在接收者线程中成功验证后，创建一个新线程用于向客户端发送数据，并将套接字的 outputStream 传递给新线程。clientSender 类包含一个队列作为缓冲区，其中包含应发送到客户端的数据。这是类clientSender：
public class ClientSender extends Thread {
private Client client=null;
private final Log logger = LogFactory.getLog(getClass());
PrintWriter outputStream=null;
private Queue<String> clientEventsQueue= new LinkedList<String>();
public ClientSender(PrintWriter outputStream, Client client){
this.outputStream=outputStream;
this.client=client;
}
public void run(){
//System.out.println("ClientSender run method called.");
while(true){
try {
Thread.sleep(10);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(!this.clientEventsQueue.isEmpty()){
this.outputStream.println(this.clientEventsQueue.remove());
}
}
}
public Client getClient(){
return this.client;
}
public void insertClientEvent(String clientEvent){
this.clientEventsQueue.add(clientEvent);
}
每当我想向我使用的客户发送一些东西时：
clientSender.insertClientEvent("some text");
问题是如果我删除 Thread.sleep(10) 我将不会在客户端收到任何东西。由于 TCP 套接字被阻塞，我认为这不应该发生。这是正常的还是我做错了什么？
编辑： 发件人线程没有“终止”。当服务器从另一个系统接收到事件时，它应该向所有客户端发送适当的信息。所以我认为最好的方案是在没有数据发送时停止线程并在有数据时启动它。所以我在 clientSender 类中尝试了这个：
public void run(){
while(true){
if(this.clientEventsQueue.isEmpty()){
break;
}
else{
try {
this.outputStream.println(this.clientEventsQueue.take());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
但现在的问题是何时启动线程？每当我想发送数据时，我都尝试启动它，但正如我所料，它不能正常工作，只发送第一个包：
clientSender.insertClientEvent(clientEvent.getEventString());
clientSender.start();
EDIT2 我想出了这个主意。它非常简单，我认为它消耗的 CPU 时间要少得多。
while(true){
while(this.clientEventsQueue.isEmpty()){
try {
Thread.sleep(300);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
try {
this.outputStream.println(this.clientEventsQueue.take());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
尽管我测试了它，但它工作得很好。你怎么看待这件事？