Question

我对一个只是拒绝正确刷新的java.net.SocketOutputStream感到沮丧！我必须忽视显而易见的事。在我下面的Groovy脚本中，我尝试连接到在我的Galaxy Nexus Android 4.0.2手机上运行的简单套接字服务器，它在我的5秒超时到期后立即给出了套接字关闭异常。

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!"
}

我尝试了所有不同的刷新方法，包括将输出流直接刷新到使用writer和冲洗的间接包装。在流关闭之前，服务器上不会显示任何数据，导致套接字关闭，从而导致任何从套接字读取的尝试崩溃。我究竟做错了什么？我也会在下面列出我的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

我在想......你在那里“它＆lt;＆lt;＆lt;＆lt;''回声测试'”。在Writer上使用它意味着afaik没有写入行结尾。由于您的服务器使用readLine，因此它期望一行结束。因此数据可能会到达，但readLine没有完成，因为它等待行的结束。然后修复例如“it＆lt;＆lt;＆lt;＆lt;'echo testing \ n'”或“it＆lt;＆lt;＆lt;＆lt;＆lt;＆lt;'＆lt;'\ n \ n'”。

现在我不太了解Android API，但是你的服务器可能在“writer.print（line）;”中遇到同样的问题，因为我认为用readLine读取一行，不包含行结尾了。但由于这不再被阅读，目前应该没有问题。

Answer 2

我终于在Blackdrag的帮助下弄明白这一点。我的问题出在多个方面。由于缺少换行符，客户端读取将挂起（建议使用blackdrag）。服务器读取循环也会挂起，因为客户端永远不会关闭其写入流。这导致了鸡和蛋的问题，其中关闭写入流关闭了关闭读取流的套接字。我最终需要输入＆＃34;协议＆＃34;，如果你愿意，这将表明会话何时完成，服务器应该停止读取，从而关闭套接字。写完＆＃34;完成＆＃34;客户端上的字符串成为该指标。工作客户端和服务器的完整来源如下:(我知道这是非常糟糕的Android代码，但最初只是为了测试我的新Galaxy Nexus上的通信，我还在学习如何使用iOS版本！）

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();
    }
}

无法刷新Groovy Socket

2 个答案: