【发布时间】：2014-12-14 19:25:59
【问题描述】：
我正在尝试创建一个 java 推送服务器模型以在我自己的机器上进行测试，这不会用于连接外部客户端，因为服务器和客户端将在同一台机器上。在客户端连接到他/她指定的端口后，他们应该发送一条他们选择的消息，该消息将被发送回给他们，以及连接到同一端口的任何其他客户端。
我遇到的问题是我在尝试此操作时收到java.net.ConnectException: Connection refused: connect。下面是客户端和服务端。
编辑：我已经花时间确保必要的端口也打开了，甚至禁用了我的防火墙，但无济于事。
服务器：
class MainServer {
// port that oir server is going to operate on
final static int port = 1234;
public static void main(String[] args) {
// this is going to model the server for the moment
System.out.println("Server has been started...");
Buffer<Messages> store = new Buffer<Messages>(10);
new Writer(store).start();
try {
ServerSocket serve = new ServerSocket(port);
while(true) {
// wait for server request
Socket socket = serve.accept();
// start thread to service request
new ServerThread(socket,store).start();
}
} catch(IOException e) {e.printStackTrace();}
}
}
class ServerThread extends Thread {
Socket socket;
Buffer<Messages> buffer;
public ServerThread(Socket s, Buffer<Messages> b) {
socket = s;buffer = b;
}
public void run() {
try {
DataInputStream in = new DataInputStream(socket.getInputStream());
int port = in.readInt();
System.out.println("Port: "+port);
Messages ms = new Messages(port);
// Read message as string from user
String message = in.readUTF();
int k = in.readInt();
while(k != -1) {
// Add message to array
// read next message
ms.add(message);
message = in.readUTF();
}
// close connection
socket.close();
// add message to buffer
buffer.put(ms);
} catch(IOException e) {e.printStackTrace();}
}
}
class Writer extends Thread {
Buffer<Messages> buffer;
public Writer(Buffer<Messages> m) {buffer = m;}
public void run() {
while(true) {
Messages dp = buffer.get();
dp.write();
}
}
}
class Buffer <E> {
/**
* Producer & Consumer Buffer
*/
private int max;
private int size = 0;
private ArrayList<E> buffer;
private Semaphore empty; //control consumer
private Semaphore full; // control producer
private Lock lock = new ReentrantLock();
public Buffer(int s) {
buffer = new ArrayList<E>();
max = s;
empty = new Semaphore(0);
full = new Semaphore(max);
}
// add data to our array
public void put(E x) {
try {
full.acquire();
} catch(InterruptedException e) {}
// sync update to buffer
lock.lock();
try {
buffer.add(x);
size++;
empty.release();
} finally {lock.unlock();}
}
public E get() {
try {
empty.acquire();
} catch(InterruptedException e) {}
// sync uodate on buffer
lock.lock();
try {
E temp = buffer.get(0);
buffer.remove(0);
size--;
full.release();
return temp;
} finally {lock.unlock();}
}
}
final class Messages {
private final int port;
private final ArrayList<String> data = new ArrayList<String>();
public Messages(int p) {port = p;}
void add(String message) {
data.add(message);
}
void write() {
try {
Socket socket;
socket = new Socket(InetAddress.getLocalHost(),port);
DataOutputStream out = new DataOutputStream(socket.getOutputStream());
// write message
out.write(data.size());
for(String k : data) {out.writeUTF(k);}
out.flush();
socket.close();
} catch(IOException e) {e.printStackTrace();}
}
}
客户：
class Client {
final static int nPort = 1234;
static int serverPort;
public static void main(String[] args) {
// this class and those present in it
// will model the client for assignment 8
Scanner in = new Scanner(System.in);
System.out.println("Please enter the messageboard number: ");
serverPort = in.nextInt();
System.out.println("Please type your message: ");
String msg = in.next();
Listener lis = new Listener(serverPort);
lis.start();
boolean go = true;
while(go) {
try {
Thread.sleep(2000);
} catch(InterruptedException e) {}
write(serverPort, msg);
System.out.println("Continue: 0/1");
int x = in.nextInt();
if(x == 0)go = false;
}
System.exit(0);
}
static void write(int port, String msg) {
try {
Socket socket;
socket = new Socket(InetAddress.getLocalHost(),port);
DataOutputStream out = new DataOutputStream(socket.getOutputStream());
// send message to port
out.writeInt(port);
out.writeUTF(msg);
// write sentinal after message has been written and close socket
out.writeInt(-1);
out.flush();
socket.close();
} catch(IOException e) {System.out.println(e);}
}
}
class Listener extends Thread {
private int port;
volatile boolean go;
public Listener(int p) {p = port;}
public void run() {
try {
ServerSocket serversock = new ServerSocket(port);
while(go) {
Socket socket = serversock.accept();
DataInputStream in = new DataInputStream(socket.getInputStream());
// Read the message
while(in.available() > 0) {
String k = in.readUTF();
System.out.print(k+" ");
}
System.out.println();
socket.close();
}
} catch(IOException e) {go = false;}
}
}
【问题讨论】：
-
“连接被拒绝”意味着没有人在另一边监听。当您运行客户端时，您确定您的服务器已启动并在同一个端口上侦听？
-
非常肯定，我先运行服务器，然后连接我的客户端。当我收到
Connection refused时，服务器仍在运行。就端口而言，我再次确定它们在同一个端口上。
标签： java multithreading concurrency client-server