java - 多客户端/服务器。处理通讯

Question

两天以来我一直在忍受这些代码。事实上，我正在开发一个具有服务器端和客户端的应用程序。服务器每秒接收客户端的请求，通过联系数据库处理请求，然后将结果返回给客户端。我这样做的方式是，如果客户端在服务器之前启动，它将继续尝试连接到给定端口和给定主机上的服务器。
1.这是服务器端:

try
    {   
        Client client = new Client(jTable1,jLabel3);
        Thread t = new Thread(client);
        t.start();

    }catch(IOException e){}

类Client.java

public class Client implements Runnable{

private int svrPort = 0;
ServerSocket serverConnect = null;
static  Socket clientSocket = null;
static  ClientConnectThread t[] = new ClientConnectThread[1000];
JTable jtable;
JLabel jlabel;

public Client(JTable table, JLabel label) throws IOException {

    this.svrPort = 9450;
    this.jtable = table;
    this.jlabel = label;

}

public void run(){
    try{
        serverConnect = new ServerSocket(this.svrPort);

    }catch(IOException e){}
    while(true){
        try{
            clientSocket = serverConnect.accept ();
            for(int i=0; i<=1000; i++){ //I can accept up to 1000 clients
        if(t[i]==null)
        {
            (t[i] = new ClientThread(client, t, jtable, jlabel)).start();
                        System.out.println ("Etat12. Apres bloc try");
            break;
        }
    }
        }catch(IOException e){}
    }
}

}

类ClientThread.java

public ClientThread(Socket socket, ClientThread t[], JTable table, JLabel label){

    this._socket = socket;
    this.jTable = table;
    this.jlabel = label;
    this.totalConnected = 0;       
    this.t = t;
}

public void run(){

    int index = 0;
    try{
        this._output = new PrintWriter(this._socket.getOutputStream ());
        this._input = new BufferedReader(new InputStreamReader(this._socket.getInputStream()));

        while((clientMsg = this._input.readLine ()) != null){
            if(clientMsg.equals ("@CONNECT")){ // If it is the first time the user is signig in, fill the table

                jTable.setValueAt (this._socket.getInetAddress (), index, 0);
                jTable.setValueAt (new Date(), index, 1);
                jTable.setValueAt (new Date(), index, 2);
                totalConnected++;
                jlabel.setText ("");
                jlabel.setText (totalConnected+"");

            }else if(Integer.parseInt (clientMsg) == 1){
                int p = Integer.parseInt (clientMsg);
                this._output = new PrintWriter(this._socket.getOutputStream(), true);
                if (this.getData.connect ())
                {
                    if(this.getData.getDataByType (1).size () == 0){
                    }
                    _output.println (this.getData.getDataByPeriod (1));
                }else{System.out.println("You are not connected to the database server");}

            }else if(Integer.parseInt (clientMsg) == 2){
                int p = Integer.parseInt (clientMsg);
                this._output = new PrintWriter(this._socket.getOutputStream(), true);
                if (this.getData.connect ())
                {
                    if(this.getData.getDataByPeriod (2).size () == 0)System.out.println ("There is no data corresponding");
                    this._output.println (this.getData.getDataByPeriod (2));
                }else{System.out.println("You are not connected to the database server");}


            }else if(Integer.parseInt (clientMsg) == 3){
                int p = Integer.parseInt (clientMsg);
                this._output = new PrintWriter(this._socket.getOutputStream(), true);
                if (this.getData.connect ())
                {
                    if(this.getData.getDataByType (3).size () == 0)System.out.println ("There is no data corresponding");
                    this._output.println (this.getData.getDataByType (30));
                }else{System.out.println("You are not connected to the database server");}


            }else if(Integer.parseInt (clientMsg) == 4){
                int p = Integer.parseInt (clientMsg);
                this._output = new PrintWriter(this._socket.getOutputStream(), true);
                if (this.getData.connect ())
                {
                    if(this.getData.getDataByType (4).size () == 0)System.out.println ("There is no data corresponding");
                    this._output.println (this.getData.getDataByType (60));
                }else{System.out.println("You are not connected to the database server");}


            }else{

            }
        }
        this._input.close ();
        this._output.close ();
    }catch(IOException e){}

}

这些是使我的服务器运行的两个类。 Client.java 类启动并等待接受连接。当客户端连接时，将创建 clientThread 实例并将其关联到客户端。到目前为止，一切似乎都进展顺利。

客户端

public class ServerConnect implements Runnable{

public static Socket clientSocket = null;
public static PrintWriter out = null;
public static BufferedReader in = null;
public static int port=9450;
public static String host = "127.0.0.1";
public static JLabel myLabel;
public static JButton button;
public static ResourceMap resourceMap;
private static String serverMsg = "";

public ServerConnect(JLabel jLabel, JButton b)
{
    jLabel.setText ("Trying to contact the server");
    myLabel = jLabel;
    button = b;
    port = Integer.parseInt("9450");
    host = "127.0.0.1";

        try{
            clientSocket = new Socket(host, port);
            }catch(IOException e){e.printStackTrace ();}

}

public void run()
{
    while(true){
        while(!this.connect ())
        {myLabel.setText ("You are not connected to the server : "+host);
         button.setEnabled (false);
            try{
                clientSocket = new Socket(host, port);
            }catch(IOException e){}
        }

        myLabel.setText ("You are connected to the server : "+host);
        button.setEnabled (true);
        try{
           out = new PrintWriter(clientSocket.getOutputStream(), true);
           out.println("@CONNECT");

           in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
           while((serverMsg = in.readLine ()) != null){
                System.out.println ("<=> :"+serverMsg);
           }
        }
        catch(IOException e){e.printStackTrace ();}
    }
}
private boolean connect()
{
    try{
        clientSocket = new Socket(host, port);
        return true;
    }catch(IOException e){}
    return false;
}}

我的问题是，当双方启动时，客户端唯一发送@CONNECT，服务器收到它，一切都停止在这里。如果客户端再次发送请求，服务器不会应答。
我希望有人逐步向我展示如何设置此应用程序
- 服务器端。使用 WHILE 循环接受线程中的连接
- 客户端。在另一个线程中每次尝试联系服务器以建立连接
- 再次在另一个线程中，客户端向服务器发送请求
- 服务器是另一个线程，从数据库请求信息并将其发送回客户端。

非常感谢您的帮助

Answer 1

哦，将所有内容都放在带有 PrintWriter 等的低级套接字上是一个坏主意。我过去遇到过一些编码和多线程错误。所以我的(当然有点慢，但易于使用)解决方案是:Jersey & Grizzly。

最大的优点是:您可以非常轻松地修改和扩展传输对象，而无需修改传输代码(低级套接字编写)

界面...

public interface I_ServiceCommons {
        public static final String  MEDIATYPE           = "text/xml";
        public static final String  MEDIATYPE_ENCODING  = I_ServiceCommons.MEDIATYPE + "; charset=utf-8";
        public static final String SERIVCENAME = "/FUNNY_SERVICE_V001";
    }

服务器端代码

@Path(I_ServiceCommons.SERIVCENAME)
public class YourService {

    @POST
    @Produces(I_ServiceCommons.MEDIATYPE)
    @Consumes(I_ServiceCommons.MEDIATYPE)
    public ResultObject request(final RequestObject yourRequest) {
        //process here your request in Server
    }
}

您的客户....

public class abstract YourAbstractClient{
        protected Logger                            log             = Logger.getLogger(this.getClass());
        protected final String                      serviceUrl;
        private final WebResource                   resource;

        public YourAbstractClient(final String url) {
            this.serviceUrl = url + getService();
            this.resource = Client.create().resource(this.serviceUrl);
        }

        public abstract String getService();

        protected <RES, REQ> RES post(final Class<RES> resultClazz, final REQ req) {
            final Builder builder = this.resource.type(I_ServiceCommons.MEDIATYPE).accept(I_ServiceCommons.MEDIATYPE);
            try {
                final RES result = builder.post(resultClazz, req);
                return result;
            } catch (final Exception e) {
                throw new RuntimeException("Error posting data to [" + this.serviceUrl + "]: " + e.getMessage(), e);
            }
        }

    }

您的服务客户端...

public class Service extends YourAbstractClient {

    public Service(final String url) {
        super(url);
    }

    public MyResult getResult(final MyRequest req) {
        return super.post(MyResult.class, req);
    }

    @Override
    public String getService() {
        return I_ServiceCommons.SERIVCENAME;
    }
}

您的 TransferObjects

@XmlRootElement
public class MyRequest implements Serializable {
    public void setRequestType(final int p_AequestType) {
        this.requestType = p_AequestType;
    }

    public int getRequestType() {
        return this.requestType;
    }
}

最后...

String url = "http://127.0.0.1";
GrizzlyServerFactory.create(url) //starts the server
MyRequest res = new MyRequest();
MyResult result = new Service(url).getResult(req); // Corrected