Java.lang.IllegalArgumentException：host = null，port = 4444

Question

如果我在模擬器中運行我的應用程序，我的應用程序立即崩潰。我得到錯誤'由於：java.lang.IllegalArgumentException：host = null，port = 4444'。 Logcat說錯誤來自InetSocketAdress。這是我的服務器代碼：

package com.imptmd.charliemacdonald.desleutelaar_v3; 

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

import java.io.BufferedReader; 
import java.io.BufferedWriter; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.io.OutputStreamWriter; 
import java.io.PrintWriter; 
import java.net.InetSocketAddress; 
import java.net.Socket; 
import java.net.SocketTimeoutException; 
import java.net.UnknownHostException; 

/** 
* Created by Charlie on 26-3-2015. 
*/ 
public class Server extends AsyncTask<Void, Void, String> { 

private String message; 
private String ip; 
public static int port = 4444; 
private String serverResponse = null; 

public Server(String ip, int port, String message) { 
    super(); 
    //IP, Port en bericht om naar server te sturen 
    this.message = message; 
    this.ip = ip; 
    this.port = port; 
} 

@Override 
protected String doInBackground(Void... params) { 
    try { 
     Socket serverSocket = new Socket(); 
     serverSocket.connect(new InetSocketAddress(this.ip, this.port), 4444); 

     this.sendMessage(message, serverSocket); 

     InputStream input; 

     try { 
      input = serverSocket.getInputStream(); 
      BufferedReader responseStreamReader = new BufferedReader(new InputStreamReader(input)); 
      String line = ""; 
      StringBuilder stringBuilder = new StringBuilder(); 
      while ((line = responseStreamReader.readLine()) != null) { 
       stringBuilder.append(line); 
      } 
      responseStreamReader.close(); 

      this.serverResponse = stringBuilder.toString(); 

     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 


     System.out.println("Response: " + serverResponse); 

    } catch (UnknownHostException e) { 
     Log.d("debug", "can't find host"); 
    } catch (SocketTimeoutException e) { 
     Log.d("debug", "time-out"); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    return serverResponse; 
} 

private void sendMessage(String message, Socket serverSocket) { 
    OutputStreamWriter outputStreamWriter = null; 

    try { 
     outputStreamWriter = new  OutputStreamWriter(serverSocket.getOutputStream()); 
    } catch (IOException e2) { 
     e2.printStackTrace(); 
    } 

    if (outputStreamWriter != null) { 
     BufferedWriter bufferedWriter = new  BufferedWriter(outputStreamWriter); 
     PrintWriter writer = new PrintWriter(bufferedWriter, true); 

     writer.println(message); 
    } 
} 
} 

類，用戶可以在IP填寫的代碼：

package com.imptmd.charliemacdonald.desleutelaar_v3; 

import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.KeyEvent; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.TextView; 
import android.widget.Toast; 

import org.json.JSONException; 
import org.json.JSONObject; 

import java.util.concurrent.ExecutionException; 


public class GebruikerIP extends Activity { 

private Boolean serverCheck; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    setTitle("Slotenbedrijf De Sleutelaar"); 

    //Check voor internet verbinding 
    if(NetwerkCheck.isInternetAvailable(GebruikerIP.this)) 
    { 
    } 
    else 
    { 
     Toast.makeText(GebruikerIP.this, "Er is helaas geen internetverbinding geconstateerd, daarom wordt nu de laatst opgehaalde informatie getoond.!", Toast.LENGTH_LONG).show(); 
    } 

    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_gebruikerip); 

    Button ipButton = (Button) findViewById(R.id.serverbutton); 
    ipButton.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View view) { 
      verbindServer(); 
     } 

    }); 

    //Enter key afvangen 
    EditText ipInvoer = (EditText) findViewById(R.id.ipinvoeren); 
    ipInvoer.setOnKeyListener(new View.OnKeyListener() { 

     public boolean onKey(View v, int keyCode, KeyEvent event) { 

      switch(keyCode) { 
       case KeyEvent.KEYCODE_ENTER: 
        verbindServer(); 
        break; 

       default: 
        return false; 
      } 

      return true; 

     } 
    }); 

} 

//server connectie maken voor ophalen van diensten 
public void verbindServer() { 
    TextView ipVeld = (TextView) findViewById(R.id.ipinvoeren); 
    String ip = ipVeld.getText().toString(); 
    Log.i("ip", ip); 

    String response = null; 
    JSONObject jsonObject = new JSONObject(); 
    try { 
     jsonObject.put("slotenlijst", ""); 
    } catch (JSONException e) { 
     e.printStackTrace(); 
    } 
    try { 
     try { 
      response = new Server(ip, 
        4444, jsonObject.toString()).execute().get(); 
      //exceptions afvangen 
     } catch (InterruptedException e) 
     { 

     } 
    } catch (ExecutionException e1) 
    { 

    } 
    if (response == null) { 
     serverCheck = false; 
     Toast.makeText(this, "Verbinden met server mislukt, staat server aan?", Toast.LENGTH_LONG).show(); 

    } else { 
     //doorgaan naar MainActivity 
     serverCheck = true; 
     HoofdschermFragment.serverIp = ip; 
     Intent startApp = new Intent(this, MainActivity.class); 
     startActivity(startApp); 

    } 
} 

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

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    // Handle action bar item clicks here. The action bar will 
    // automatically handle clicks on the Home/Up button, so long 
    // as you specify a parent activity in AndroidManifest.xml. 
    int id = item.getItemId(); 

    return super.onOptionsItemSelected(item); 
} 
} 

我不能找出如何解決這個錯誤。幫助，我會感激。謝謝！

Answer 1

將其更改爲

InetAddress inetServer = InetAddress.getByName(IP); 

比

Socket socket = new Socket(inetServer, devicePort); 

，如果您使用的不是使用下面一行

ServerSocket socket = new ServerSocket(devicePort,int backlognumber, inetServer);