Java的插座 - 服務器的響應總是空

Question

我必須與服務器（我不能夠訪問服務器代碼），但傳輸協議（插座）連接是：

（客戶端） - - >數據

ACK < - （服務器）
數據響應< - （服務器）

（客戶端） - > ACK

假設服務器應該總是快速響應。我連接到服務器，我發送數據但響應爲NULL，如果我調試我的代碼，當我捕獲響應時發生異常： 「java.net.SocketException：軟件導致連接中止：recv失敗」

我的代碼：

public static void main(String[] args){ 
    try{ 
     String order = "datahere"; 
     String responseServer; 
     BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in)); 

     Socket clientSocket = new Socket(); 
     InetSocketAddress sa = new InetSocketAddress("XXX.XX.XX.XX", 9300); 
     clientSocket.connect(sa,500); 

     DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream()); 
     BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));  
     outToServer.writeBytes(order); 
     responseServer = inFromServer.readLine();//exception if I try to debug my code 
     System.out.println("From server: " + responseServer); //responseServer is NULL 
     clientSocket.close(); 

    } catch (IOException ex) { 
      System.out.println("Error: "+ex); 
    } 

} 

這是怎麼回事？任何想法？

我試圖禁用防火牆，並添加規則的端口9300，但結果是一樣的。

客戶給了我一個示例代碼中Vb.Net，它應該工作，我試圖複製它在Java中。

守則Vb.Net：

Dim message As String = "datahere"; 

Try 
    Dim data As [Byte]() = System.Text.Encoding.ASCII.GetBytes(message) 

    Dim client As New TcpClient(ip, port) 
    Dim stream As NetworkStream = client.GetStream() 
    stream.Write(data, 0, data.Length) 

    data = New [Byte](2048) {} 

    Dim responseData As [String] = [String].Empty 
    Dim bytes As Integer = stream.Read(data, 0, data.Length) 
    responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes) 

    stream.Close() 
    client.Close() 

Catch ex As Exception 

End Try 

SOLUTION：

Socket clientSocket = new Socket(); 
InetSocketAddress sa = new InetSocketAddress("XXX.XX.XX.XX", 9300); 
clientSocket.connect(sa,500); 

clientSocket.getOutputStream().write(order.getBytes("ASCII")); 

byte[] data = new byte[2048]; 
int bytes = clientSocket.getInputStream().read(data, 0, data.length); 
String responseData = new String(data, 0, bytes, "ASCII"); 
System.out.println("From server: " + responseData); 

//Another way to catch the response: 
//InputStreamReader in = new InputStreamReader(clientSocket.getInputStream()); 
//int data1 = in.read(); 
//while(data1 != -1) { 
// System.out.print((char) data1); 
// data1 = in.read(); 
//} 

clientSocket.close(); 

Answer 1

這是你VB code的翻譯java

public static void main(String[] args) throws IOException { 
    String order = "datahere"; 

    // Try-with-resource statement will close your socket automatically 
    try (Socket clientSocket = new Socket("XXX.XX.XX.XX", 9300)) { 
     // Send to the sever the order encoded in ASCII 
     clientSocket.getOutputStream().write(order.getBytes("ASCII")); 
     // Sleep until we have bytes to read available 
     while (clientSocket.getInputStream().available() == 0) { 
      Thread.sleep(100L); 
     } 
     // Create the buffer of exactly the amount of bytes available without blocking 
     byte[] data = new byte[clientSocket.getInputStream().available()]; 
     // Read the bytes from the server and put it into the buffer 
     int bytes = clientSocket.getInputStream().read(data, 0, data.length); 
     // Decode what has been read from the server that was encoded in ASCII 
     String responseData = new String(data, 0, bytes, "ASCII"); 
     System.out.println("From server: " + responseData); 
    } 
} 

Answer 2

DataInputStream dis = new DataInputStream(new InputStreamReader(clientSocket.getInputStream())); 

    while(dis.available()>0){ 
    //reads characters encoded with modified UTF-8 
    String temp = dis.readUTF(); 
    System.out.print(temp+" "); 
     } 

嘗試使用dataInputStream代替bufferedReader和使用readUTF()方法dataInputStream閱讀UTF字符。