【问题标题】:Converting java.net.Socket.getInputStream() to byte[] showing large delay将 java.net.Socket.getInputStream() 转换为 byte[] 显示大延迟
【发布时间】:2016-09-28 06:10:45
【问题描述】:

我设计了一个 Java Client 类,需要通过套接字将 byte[] 数组发送到 Java Server 类。这是我的代码:

ByteArrayClient.java

import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.net.Socket;

public class ByteArrayClient {

public static void main(String[] args) {


        //make POJO__________________________
        ByteEncodeSubscriptionReq sr1=ByteEncodeSubscriptionReq.makeRequest(103, "Str1", "Str2");

        //Connection details____________________
        String serverName = "localhost";
        int port = 6060;
        try {

            //Establish Connection with server_______________________________
            System.out.println("ByteArrayClient: Connecting to " + serverName +":" + port+"...");
            Socket client = new Socket(serverName, port);//make new socket
            System.out.println("ByteArrayClient: connected to " + client.getRemoteSocketAddress());

            //Encode POJO to ByteArray________________________________
            byte[] SubscripReqByteArray=ByteEncodeSubscriptionReq.encode(sr1);
             //encoded correctly to a 44 bit byte array
            System.out.println("ByteArrayClient: SubscripTionRequest successfully encoded");

            //Send POJO ByteArray to server__________________________
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            ObjectOutputStream os = new ObjectOutputStream(out);
            os.write(SubscripReqByteArray);;

            System.out.println("ByteArrayClient: POJO sent to server");

            //Receive Server response_________________________________
            InputStream inFromServer = client.getInputStream();
            DataInputStream in = new DataInputStream(inFromServer);
            System.out.println("ByteArrayClient received: " + in.readUTF());

            //close socket____________________________________
            client.close();


        } catch (IOException e) {

            e.printStackTrace();
            System.out.println("PojoClient: Connection Failed");
        }

    }

}

...和 ​​ByteArrayServer.java

import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketTimeoutException; 


public class ByteArrayServer extends Thread{

        private ServerSocket serverSocket;

        public ByteArrayServer(int port) throws IOException {
            serverSocket = new ServerSocket(port);//create server socket 
            serverSocket.setSoTimeout(15000);//socket closes after 15 seconds
            this.start();
        }

        public void run() {
            while (true) {//server runs infinitely______________
                try {

                    System.out.println("ByteArrayServer: Waiting for client on port " + serverSocket.getLocalPort() + "...");
                    Socket servedClient = serverSocket.accept();//client socket

                    System.out.println("ByteArrayServer: connected to " + servedClient.getRemoteSocketAddress());

                    //Receive Client ByteArray___________________________________________
                    ByteEncodeSubscriptionReq receivedReq=new ByteEncodeSubscriptionReq();//server side POJO
                    System.out.println("ByteArrayServer: created SubscriptionReq Object");
                    InputStream PojoStreamHolder = servedClient.getInputStream();
                    System.out.println("ByteArrayServer: client InputStream received");
                    byte[] clientByteStream=new byte[44];//same size as Pojo byte requirement


                    _____/*MY CODE IS STUCK SOMEWHERE HERE*/__________      



                    servedClient.getInputStream().read(clientByteStream);

                    System.out.println("ByteArrayServer: clientByteStream received: "+clientByteStream[0]+" "+clientByteStream[1]);
                    receivedReq=ByteEncodeSubscriptionReq.decode(clientByteStream);

                    //Send confirmation to Client__________________________________________________
                    DataOutputStream out = new DataOutputStream(servedClient.getOutputStream());
                    if(receivedReq.getRequestSymbol().trim().length()!=0){
                            out.writeUTF("ByteArrayServer received Subscription ID="+receivedReq.getSubscriptionID());
                            System.out.println("ByteArrayServer: new SubscriptionRequest ID="+receivedReq.getSubscriptionID()+" Subscriber_Name="+receivedReq.getSubscriberName());
                    }else{
                            out.writeUTF("ByteArrayServer: did not receive Subscription ID");
                    }
                    //Close Client socket_________________________________________________________
                    //server.close();

                    //serverSocket.close();



                } catch (SocketTimeoutException s) {
                    System.out.println("PojoServer: Socket timed out after " + getTimeElapsedInSeconds(startTime) + " seconds from start");
                    break;
                } catch (IOException e) {
                    e.printStackTrace();
                    break;
                }
            }
        }



        public static void main(String[] args) {
            // int port = Integer.parseInt(args[0]);//to get port as an Argument
            int port = 6060;
            try {
                Thread t = new ByteArrayServer(port);
                startTime = System.currentTimeMillis();

            } catch (IOException e) {
                e.printStackTrace();
            }
        }


    }

这是服务器控制台输出:

ByteArrayServer: Waiting for client on port 6060...
ByteArrayServer: connected to /127.0.0.1:64233
ByteArrayServer: created SubscriptionReq Object
ByteArrayServer: client InputStream received

问题是,虽然服务器接收到 Stream 时没有错误,但它会卡在 serveClient.getInputStream().read(clientByteStream); 附近。方法,不再继续。

我也试过了

int count=servedClient.getInputStream().read(clientByteStream);

DataInputStream in = new DataInputStream(servedClient.getInputStream());
long bStr=in.readLong();

ObjectInputStream PojoObjHolder = new ObjectInputStream(PojoStreamHolder);
byte[] clientByteStream2 = (byte[])PojoObjHolder.readObject();

..但它们也显示出同样的问题。

我应该如何在两个类之间传递字节数组而不需要额外的导入?

【问题讨论】:

  • 您的代码毫无意义。您使用ObjectOutputStream 发送到服务器并使用DataInputStream 在服务器上读取。
  • 感谢您的意见。我已经做出了改变
  • 事实上你还没有向服务器写任何东西。仅限ByteArrayOutputStream。不知道你说的是什么变化。我没有推荐一个。

标签: java arrays sockets datainputstream


【解决方案1】:

问题出在我的 ByteArrayClient 类中。我必须将 OutputStream 与客户端套接字链接,而不是创建它的新实例。所以我换了:

ByteArrayOutputStream out = new ByteArrayOutputStream();
ObjectOutputStream os = new ObjectOutputStream(out);
os.write(SubscripReqByteArray);;

OutputStream os = client.getOutputStream(out);
os.write(SubscripReqByteArray);;

谢谢你的提示Ekant

【讨论】:

    【解决方案2】:

    DataInputStream.readFully(byte[] b) 仅在输入流字节中直到 b.length 可用时才会完成。所以如果你有所有的字节,你肯定需要调试。解决方案是让这些字节可用,以便函数完成。 DataInputStream.read(byte[] b) 方法相同,直到输入数据可用。 请通过调试您的应用程序确保输入流有 44 个字节。 尝试在下面计算可用字节数,您可以轻松读取它们。

    // 计算输入流的可用字节数 int count = is.available();

         // create buffer
         byte[] bs = new byte[count];
    
         // read data into buffer
         dis.read(bs);
    

    【讨论】:

    • 您关于DataInputStream.read(byte[] b) 的声明似乎暗示它的行为与DataInputStream.readFully(byte[] b) 相同,但事实并非如此。请澄清。
    • 感谢 EJP,但主要区别在于读取精确字节,因为 b 的长度和 read can read 可能小于 b 的长度
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