无法刷新Groovy套接字

Question

我越来越沮丧在java.net.SocketOutputStream，只是拒绝正确刷新！我必须忽视这个明显的问题。在我下面的Groovy脚本中，我尝试连接到在Galaxy Nexus Android 4.0.2手机上运行的简单套接字服务器，并在我的5秒超时过期后立即给出套接字关闭异常。

SocketClient.groovy

import java.net.* 
socket = new Socket() 
socket.connect(new InetSocketAddress(InetAddress.getByAddress([172,17,57,21] as byte[]), 58789), 5000) 
println "Connected!" 
socket.withStreams { input, output -> 
    println "Processing ${input.class.name} and ${output.class.name} streams..." 
    output.withWriter { 
     it << 'echo testing\n\n'; 
     it.flush(); 
     output.flush() 
     def readerThread = Thread.start { 
      println "Request written, reading response..."; println input.text 
     } 
     println "Waiting 5 secs for read to complete." 
     readerThread.join(5000) 
    } 
    println "Stream closed!" 
} 

我试过冲洗所有不同的手段，包括输出流间接包装与作家和冲洗的直接冲洗。在数据流关闭之前服务器上没有数据出现，导致套接字关闭，导致套接字读取尝试失败。我究竟做错了什么？我也会在下面嵌入我的Android代码。这是一个启动套接字服务器的简单活动。

MyServer.java

package com.example; 

import android.app.Activity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.TextView; 

public class MyServer extends Activity 
{ 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
     RawSocketServer rawSocketServer = new RawSocketServer(); 
     String port = rawSocketServer.getLocalPort(); 
     TextView textView = (TextView) this.findViewById(R.id.mainTextView); 
     textView.setText("Server bound to port " + port); 
     rawSocketServer.start(); 
    } 
} 

RawSocketServer.java

package com.example; 

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.io.PrintWriter; 
import java.net.ServerSocket; 
import java.net.Socket; 

/** 
* Created by IntelliJ IDEA. 
* User: cliff 
* Date: 5/9/12 
* Time: 4:03 PM 
*/ 
public class RawSocketServer { 

    public static final int PORT = 0; 
    private ServerSocket serverSocket; 

    public RawSocketServer() { 
     this(PORT); 
    } 

    public RawSocketServer(int port) { 
     try { 
      this.serverSocket = new ServerSocket(port); 
     } catch (IOException e) { 
      e.printStackTrace(); 
      throw new RuntimeException("server cannot bind to port " + port); 
     } 
    } 

    public void start() { 
     new Thread(new Runnable() { 
      public void run() { 
       go(); 
      } 
     }).start(); 
    } 

    private void go() { 
     Socket socket = null; 
     while (true) { 
      try { 
       socket = this.serverSocket.accept(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
       throw new RuntimeException("cannot accept from server socket" + e); 
      } 
      BufferedReader reader = null; 
      try { 
       reader = new BufferedReader(new InputStreamReader(socket.getInputStream())); 
      } catch (IOException e) { 
       e.printStackTrace(); 
       throw new RuntimeException("Could not get input stream from socket. " + e); 
      } 
      PrintWriter writer = null; 
      try { 
       writer = new PrintWriter(socket.getOutputStream()); 
      } catch (IOException e) { 
       e.printStackTrace(); 
       throw new RuntimeException("Could not get output stream from socket. " + e); 
      } 
      try { 
       for (String line = reader.readLine(); line !=null; line = reader.readLine()) { 
        writer.print(line); 
       } 
      } catch (IOException e) { 
       e.printStackTrace(); 
       throw new RuntimeException("Error reading/writing from/to socket. " + e); 
      } 
     } 
    } 

    public String getLocalPort() { 
     return "" + serverSocket.getLocalPort(); 
    } 
} 

Answer 1

我想知道....你有 “它< < '回响测试'” 有。在Writer上使用它意味着不写行结束。由于您的服务器使用readLine，因此需要一行结束。因此数据可能会到达，但readLine并未完成，因为它等待行结束。然后，修复程序就会执行例如“它< <'回声测试\ n'”或“它< <'回声测试'< <'\ n'”。

现在我不太了解Android API，但是您的服务器在“writer.print（line）;”中可能有相同的问题，因为我认为使用readLine读取的一行不包含该行结束了。但由于这不再读，现在应该没有问题。

Answer 2

我终于明白了这一点与Blackdrag的帮助。我的问题是在多个领域。客户端读取会因为缺少新行而挂起（如blackdrag建议）。此外，服务器读取循环会挂起，因为客户端永远不会关闭其写入流。这会导致鸡和蛋的问题，关闭写入流会关闭关闭读取流的套接字。如果你愿意的话，我最终需要添加一个“协议”，这将指示对话何时完成，服务器应该停止读取并关闭套接字。在客户端写入“完成”字符串就成了该指标。下面是工作客户端和服务器的完整源代码：（我知道这是非常糟糕的Android代码，但它最初只是为了测试我的新Galaxy Nexus上的通信，我仍然在学习如何使用iOS空间！）

SocketClient.groovy

import java.net.* 
socket = new Socket() 
socket.connect(new InetSocketAddress(InetAddress.getByAddress([172,17,57,21] as byte[]), 58302), 5000) 
println "Connected!" 
socket.withStreams { input, output -> 
    println "Processing ${input.class.name} and ${output.class.name} streams..." 
    output.withWriter { 
     it << 'my name is cliff\ndone\n'; 
     it.flush(); 
     output.flush() 
     def readerThread = Thread.start { 
      println "Request written, reading response..."; println input.text 
     } 
     println "Waiting 5 secs for read to complete." 
     readerThread.join(60000) 
    } 
    println "Stream closed!" 
} 

MyServer.java

package com.example; 

import android.app.Activity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.TextView; 

public class MyServer extends Activity 
{ 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
     RawSocketServer rawSocketServer = new RawSocketServer(); 
     String port = rawSocketServer.getLocalPort(); 
     TextView textView = (TextView) this.findViewById(R.id.mainTextView); 
     textView.setText("Server bound to port " + port); 
     rawSocketServer.start(); 
    } 
} 

RawSocketServer.java

package com.example; 

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.io.PrintWriter; 
import java.net.ServerSocket; 
import java.net.Socket; 

/** 
* Created by IntelliJ IDEA. 
* User: cliff 
* Date: 5/9/12 
* Time: 4:03 PM 
*/ 
public class RawSocketServer { 

    public static final int PORT = 0; 
    private ServerSocket serverSocket; 

    public RawSocketServer() { 
     this(PORT); 
    } 

    public RawSocketServer(int port) { 
     try { 
      this.serverSocket = new ServerSocket(port); 
     } catch (IOException e) { 
      e.printStackTrace(); 
      throw new RuntimeException("server cannot bind to port " + port); 
     } 
    } 

    public void start() { 
     new Thread(new Runnable() { 
      public void run() { 
       go(); 
      } 
     }).start(); 
    } 

    private void go() { 
     Socket socket = null; 
     while (true) { 
      try { 
       socket = this.serverSocket.accept(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
       throw new RuntimeException("cannot accept from server socket" + e); 
      } 
      BufferedReader reader = null; 
      try { 
       reader = new BufferedReader(new InputStreamReader(socket.getInputStream())); 
      } catch (IOException e) { 
       e.printStackTrace(); 
       throw new RuntimeException("Could not get input stream from socket. " + e); 
      } 
      PrintWriter writer = null; 
      try { 
       writer = new PrintWriter(socket.getOutputStream()); 
      } catch (IOException e) { 
       e.printStackTrace(); 
       throw new RuntimeException("Could not get output stream from socket. " + e); 
      } 
      try { 
       for (String line = reader.readLine(); line !=null; line = reader.readLine()) { 
        if(line.trim().equalsIgnoreCase("done")) break; 
        writer.println(line); 
        writer.flush(); 
       } 
       writer.close(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
       throw new RuntimeException("Error reading/writing from/to socket. " + e); 
      } 
     } 
    } 

    public String getLocalPort() { 
     return "" + serverSocket.getLocalPort(); 
    } 
}