Question

我想问一下android socket的一些问题。我创建了一个示例应用程序来将数据发送到wifly模块。但是，当我从模块接收数据时，我得到套接字超时异常。没有setSoTimeout应用冻结到inputStream.read。这是我的代码：

    package com.socket.wiflysocket;

import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {

    protected static final String TAG = "WIflySocket";

    EditText textOut;
    TextView textIn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

         textOut = (EditText)findViewById(R.id.textout);
         Button buttonSend = (Button)findViewById(R.id.send);
         textIn = (TextView)findViewById(R.id.textin);
         buttonSend.setOnClickListener(buttonSendOnClickListener);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    Button.OnClickListener buttonSendOnClickListener
        = new Button.OnClickListener(){

            @Override
            public void onClick(View arg0) {

                ConnectivityManager connMgr = (ConnectivityManager) 
                    getSystemService(Context.CONNECTIVITY_SERVICE);
                NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
                if (networkInfo == null || networkInfo.isConnected() == false) {
                   try {
                       throw new Exception("Network is not connected");
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
                else {
                    new SocketThread(textOut.getText().toString()).execute();

                    textOut.setText("");
                }
            }};
}

和asynkTask：

package com.socket.wiflysocket;


import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

import android.os.AsyncTask;
import android.util.Log;

public class SocketThread extends AsyncTask<String, Void, String>{

    private static final String TAG = "SocketAsyncTask";

    private static final int BUFFER_SIZE = 8;

    private String textViewIn;

    private String output;

    private Socket socket = null;

    private PrintWriter outputStream;

    private InputStreamReader inputStream;

    public SocketThread(String paramTextViewIn)
    {
        this.textViewIn = paramTextViewIn;
    }

    @Override
    protected String doInBackground(String ...views) {
        Log.d(TAG, "Execute");

        DataOutputStream dataOutputStream = null;
        DataInputStream dataInputStream = null;

         try {
            socket = new Socket("1.2.3.4", 2000);
            socket.setSoTimeout(2000);

            outputStream = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
            inputStream = new InputStreamReader(socket.getInputStream());

            if(socket.isConnected()) {

                this.sendDataWithString(textViewIn);

                output = this.receiveDataFromServer();
            }

            this.closeSocket();

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

            if (dataOutputStream != null){
                try {
                    dataOutputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            if (dataInputStream != null){
                try {
                    dataInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
         }

         return output;
    }
    /*
    // onPostExecute displays the results of the AsyncTask.
    @Override
    protected void onPostExecute(String result) {
        return textViewOut;
   }
    */

    private void closeSocket() {
        if (socket != null) {
            if (socket.isConnected()) {
                try {
                    inputStream.close();
                    outputStream.close();
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private void sendDataWithString(String message) {
        if (message != null) {
            outputStream.write(message);
            outputStream.flush();
        }
    }

    private String receiveDataFromServer() {
        String message = "";
        try {
            int charsRead = 0;
            char[] buffer = new char[BUFFER_SIZE];

            while ((charsRead = inputStream.read(buffer)) != -1) {
                message += new String(buffer).substring(0, charsRead);
            }

            closeSocket();
            return message;
        } catch (IOException e) {

            //TODO work around
            return message;
            //return "Error receiving response:  " + e.getMessage();
        }
    }

}

我添加的权限是：

android.permission.INTERNET; android.permission.ACCESS_NETWORK_STATE

你能建议我，出了什么问题，以及如何解决这个问题。谢谢

Answer 1

试试这个 -

BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
String userInput;    
    while ((userInput = stdIn.readLine()) != null) {
        out.println(userInput);
        System.out.println("echo: " + in.readLine());
    }

或者这个 -

Reader r = new InputStreamReader(conn.getInputStream());
String line;

StringBuilder sb = new StringBuilder();
char[] chars = new char[4*1024];
int len;
while((len = r.read(chars))>=0) {
    sb.append(chars, 0, len);
}

或者这个 -

byte[] resultBuff = new byte[0];
byte[] buff = new byte[1024];
int k = -1;
while((k = sock.getInputStream().read(buff, 0, buff.length)) > -1) {
    byte[] tbuff = new byte[resultBuff.length + k];
    System.arraycopy(resultBuff, 0, tbuff, 0, resultBuff.length); bytes
    System.arraycopy(buff, 0, tbuff, resultBuff.length, k);
    resultBuff = tbuff; 
}

Answer 2

SocketFactory为你创建套接字

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

import javax.net.SocketFactory;

...

private Socket socket = null;
public Reader reader = null;
public Writer writer = null;

protected void init(String host, int port) throws ClientException {
    try {
        socket = SocketFactory.getDefault().createSocket(host, port);
    } catch (UnknownHostException e) {
            throw new ClientException(e);
    } catch (IOException e) {
        throw new ClientException(e);
    }
    initDataManagers();
}
protected void initDataManagers() throws ClientException {
        try {
            reader = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));
            writer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream(), "UTF-8"));
        } catch (UnsupportedEncodingException e) {
            throw new ClientException(e);
        } catch (IOException e) {
            throw new ClientException(e);
        }   
}

android socket jelly bean

2 个答案: