Java SSL 套接字通信 - 发送和接收

Question

假设客户端向服务器发送消息，然后服务器回复客户端。

客户端代码

public void run() {
    try {
        SSLSocketfactory f = (SSLSocketFactory) SSLSocketFactory.getDefault();
        SSLSocket socket = (SSLSocket) f.createSocket(Common.JSON_SERVER_IP, Integer.parseInt(Common.JSON_SERVER_PORT));
        String[] suites = socket.getSupportedCipherSuites();
        socket.setEnabledCipherSuites(suites);

        Log.i("Socket", "Created");
        DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
        File f = new File(Common.PATH, Common.JSON_FILE_NAME);
        FileInputStream fis = new FileInputStream(f);

        byte sendBytes[] = new byte[1024];
        int fileSize = 0;
        int length = 0;

        // Data Send Start!
        while ((length = fis.read(sendBytes, 0, sendBytes.length)) > 0) {
            fileSize += length;
            dos.write(sendBytes, 0, length);
            dos.flush();
        }

        Log.i("Socket", "Data Send Finish");
        final int final_fileSize = fileSize;
        activity.runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(activity.getApplicationContext(), "JSON File Size :" + final_fileSize + "Bytes", Toast.LENGTH_SHORT).show();
            }
        });

        Log.i("Socket", "Output Close");
        // Data Receive Start!
        InputStream is = socket.getInputStream();
        BufferedReader br = new BufferedReader(new InputStreamReader(is));

        // receive the response from Server
        String reply = "";
        String str = "JSON";
        Log.i("Socket", "Receive Ready");
        /* Example result from Server 
        {
            "ret":[{"id":"COM_DATA_002","errCd":0, "errMsg":""}],
            "Value":[{"updateType":0, "fileURL":"http://127.0.0.1/filePath"}]
        }*/
        while ((reply = br.readLine()) != null) {
            Log.i("Socket", "Parsing");
            Object obj_p=JSONValue.parse(reply);
            JSONObject obj_j=(JSONObject)obj_p;
            Object target = obj_j.get("Value");
            JSONArray obj_value = (JSONArray)target;
            JSONObject url_val=(JSONObject)obj_value.get(0);
            String url = (String)url_val.get("fileURL");
            URL urlDB = new URL(url);
            URLConnection getDB = urlDB.openConnection();
            // Get New DB or query
        }
        Log.i("Socket", "File Get");
        if(str.length() != 0) {
            str = "[" + Common.getDateCurrentTimeZone(System.currentTimeMillis()) + "]\n" + str + "\n"; 
            Log.i(Common.TAG, str);
        }

        final String text = str;
        is.close();
        br.close();

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (dos != null)
            try {
                dos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        if (fis != null)
            try {
                fis.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        if (socket != null)
            try {
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
    }
}

服务器代码

public void run() {
    String fileName = "JSON.txt";

    try {
        // receive file
        receiveFile(fileName);

        // load receive file
        File file = new File(Common.defaultReceivedData, fileName);
        BufferedReader in = new BufferedReader(new FileReader(file));
        // String SendfileName = "ClientVersion.txt";
        String SendfileName = "Return.txt";
        File SendFile = new File(Common.defaultSendData, SendfileName);
        String s;
        Object obj;
        JSONObject obj2;
        String det;

        // File write and send...

        in.close();

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

public static void receiveFile(String fileName) throws IOException{

    int length = 0;
    int size = 0;

    DataInputStream dis = new DataInputStream(send.getInputStream());
    fileName = "JSON.txt";
    FileOutputStream fos = new FileOutputStream(new File(Common.defaultReceivedData, fileName));

    byte[] inputByte = new byte[1024];
    while ((length = dis.read(inputByte, 0, inputByte.length)) > 0) {
        System.out.println(length);
        size += length;
        fos.write(inputByte, 0, length);
        fos.flush();
    }
    fos.close();
    System.out.println("Received JSON data! [FileSize: " + size + "]");
}

当客户端向服务器发送消息时，通信卡住了。

客户

03-11 15:38:46.476: I/Socket(30160): Created
03-11 15:38:46.606: I/Socket(30160): Data Send Finish
03-11 15:38:46.606: I/Socket(30160): Output Close
03-11 15:38:46.616: I/Socket(30160): Receive Ready

服务器

Client is connected: IP is xxx.xxx.xxx.xxx
57

在此代码中，服务器仅在客户端停止后才完成接收消息。 可以做些什么来正常完成这个通信？

Answer 1

服务器正在从套接字读取文件，直到流结束。

客户端不会关闭连接，而是尝试从服务器读取响应，直到流结束。

所以两个对等点都没有关闭连接，所以流的结尾永远不会到达，所以双方都被阻塞在读取中，所以你已经实现了网络死锁。

您需要在文件之前发送文件的长度，以便服务器知道何时停止读取。

或者，如果您只打算每个连接发送一个文件，客户端可以关闭连接以进行输出，这将为服务器提供它的 EOS寻找，然后它的读取循环将终止，它会发送它的回复，然后关闭连接，这将给客户端 EOS it 正在寻找，所以它会掉出 它的读取循环并关闭连接。