请有人告诉我在这段代码中我可以在哪里找到Null Pointer Exception ...它会很感激。
这是群发消息的聊天代码，我正在尝试在我的emaluator上运行，但它在空指针异常时显示错误。
package edu.buffalo.cse.cse486586.groupmessenger;
public class GroupMessengerActivity extends Activity {
private int emulator_instance;
final String localHost="127.0.0.1";
boolean test2=false;
final int sequencerNumber = 5554;
static int globalClock,localClock,sequenceNumberLocalApp;
static int avd0LocalClock,avd1LocalClock,avd2LocalClock;
Map<Long,String> holdbackQueue;
Map<Long,Integer> sequenceQueue;
Map<String,String> sequenceOrderingQueue;
ContentValues cv_pushToContentProvider;
private ContentResolver mContentResolver;
private Uri mUri;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_group_messenger);
TelephonyManager tel = (TelephonyManager) this.getSystemService(Context.TELEPHONY_SERVICE);
String portStr = tel.getLine1Number().substring(tel.getLine1Number().length());
emulator_instance=Integer.parseInt(portStr);
mUri = buildUri("content", "edu.buffalo.cse.cse486586.groupmessenger.provider");
mContentResolver=getContentResolver();
createServer();
holdbackQueue = new HashMap<Long, String>();
sequenceQueue = new HashMap<Long, Integer>();
if(emulator_instance == sequencerNumber)
{
sequenceOrderingQueue = new HashMap<String,String>();
}
TextView tv = (TextView) findViewById(R.id.textView1);
tv.setMovementMethod(new ScrollingMovementMethod());
findViewById(R.id.button1).setOnClickListener(
new OnPTestClickListener(tv, getContentResolver()));
}
private Uri buildUri(String scheme, String authority) {
Uri.Builder uriBuilder = new Uri.Builder();
uriBuilder.authority(authority);
uriBuilder.scheme(scheme);
return uriBuilder.build();
}
private void createServer()
{
new Thread(new Runnable()
{
public void run()
{
try
{
ServerSocket s = new ServerSocket(10000);
while(true)
{
Socket ss=s.accept();
String msg_ServerSide=null;
BufferedReader br=new BufferedReader(new InputStreamReader(ss.getInputStream()));
msg_ServerSide=br.readLine();
//System.out.println(msg_ServerSide);
String[] message=msg_ServerSide.split(",");
//System.out.println(message.length);
if(message.length > 3)
{
testCaseMultiCastMessage();//testCase2
}
if(message[0].equals("sequenceMessage"))
{
if(localClock+1 == Integer.parseInt(message[2]))
{
if(sequenceQueue.containsKey(Long.parseLong(message[1])))
{
String upMesg=holdbackQueue.get(Long.parseLong(message[1]));
new displayMessage().execute(upMesg);
localClock++;
holdbackQueue.remove(Long.parseLong(message[1]));
sequenceQueue.remove(Long.parseLong(message[1]));
checkSQ((localClock+1));
}
else if(holdbackQueue.containsKey(Long.parseLong(message[1])))
{
String upMesg=holdbackQueue.get(Long.parseLong(message[1]));
new displayMessage().execute(upMesg);
localClock++;
checkSQ(localClock+1);
holdbackQueue.remove(Long.parseLong(message[1]));
}
else if(!sequenceQueue.containsKey(Long.parseLong(message[1])))
{
sequenceQueue.put(Long.parseLong(message[1]), Integer.parseInt(message[2]));
}
}
else
{
if(!sequenceQueue.containsKey(Long.parseLong(message[1])))
{
sequenceQueue.put(Long.parseLong(message[1]), Integer.parseInt(message[2]));
}
}
}
else
{
if(emulator_instance == sequencerNumber)
{
//System.out.println(message[0]);
String [] locArr=message[0].split(":");
String localClockCheck=locArr[0];
int localMessageClock=Integer.parseInt(locArr[1]);
if(localClockCheck.equals("avd0"))
{
if((avd0LocalClock)==localMessageClock)
{
multiCastSequence(message[1]);
avd0LocalClock++;
orderingQueueCheck(0);
}
else
{
sequenceOrderingQueue.put(message[0], message[1]);
}
}
else if(localClockCheck.equals("avd1"))
{
if((avd1LocalClock)==localMessageClock)
{
multiCastSequence(message[1]);
avd1LocalClock++;
orderingQueueCheck(1);
}
else
{
sequenceOrderingQueue.put(message[0], message[1]);
}
}
else if(localClockCheck.equals("avd2"))
{
if((avd2LocalClock)==localMessageClock)
{
multiCastSequence(message[1]);
avd2LocalClock++;
orderingQueueCheck(2);
}
else
{
sequenceOrderingQueue.put(message[0], message[1]);
}
}
}
if(!holdbackQueue.containsKey(Long.parseLong(message[1])))
{
holdbackQueue.put(Long.parseLong(message[1]), message[0]);
checkSQ(localClock+1);
}
//System.out.println(holdbackQueue+" "+sequenceQueue+" "+sequenceOrderingQueue);
if(holdbackQueue!=null && sequenceQueue!=null && sequenceOrderingQueue!=null)
{
//System.out.println(holdbackQueue.size()+" "+sequenceQueue.size()+" "+sequenceOrderingQueue.size());
}
br.close();
ss.close();
}
}
} catch (IOException e)
{
e.printStackTrace();
}
}
private void orderingQueueCheck(int ii) {
Set<String> checkString=sequenceOrderingQueue.keySet();
Iterator<String> i=checkString.iterator();
while(i.hasNext())
{
String shouldIMultiCastMessage=(String)i.next();
String [] here=shouldIMultiCastMessage.split(":");
int clockVal=Integer.parseInt(here[1]);
if(ii == 0)
{
if((avd0LocalClock) == clockVal)
{
multiCastSequence(sequenceOrderingQueue.get(shouldIMultiCastMessage));
avd0LocalClock++;
sequenceOrderingQueue.remove(shouldIMultiCastMessage);
orderingQueueCheck(0);
break;
}
}
else if(ii == 1)
{
if((avd1LocalClock) == clockVal)
{
multiCastSequence(sequenceOrderingQueue.get(shouldIMultiCastMessage));
avd1LocalClock++;
sequenceOrderingQueue.remove(shouldIMultiCastMessage);
orderingQueueCheck(1);
break;
}
}
else if(ii == 2)
{
if((avd2LocalClock) == clockVal)
{
multiCastSequence(sequenceOrderingQueue.get(shouldIMultiCastMessage));
avd2LocalClock++;
sequenceOrderingQueue.remove(shouldIMultiCastMessage);
orderingQueueCheck(2);
break;
}
}
}
}
private void multiCastSequence(String string)
{
globalClock++;
String seqMessage="sequenceMessage"+","+string+","+globalClock;
multiCastMessage(seqMessage);
}
private void checkSQ(int lc)
{
if(sequenceQueue.containsValue(lc))
{
Set<Long> keys= sequenceQueue.keySet();
Iterator<Long> it=keys.iterator();
while(it.hasNext())
{
Long l=(Long)it.next();
if(sequenceQueue.get(l)==lc)
{
String upMesg=holdbackQueue.get(l);
new displayMessage().execute(upMesg);
localClock++;
holdbackQueue.remove(l);
sequenceQueue.remove(l);
checkSQ(localClock+1);
break;
}
}
}
else
{
return;
}
}
}).start();
}
class displayMessage extends AsyncTask<String, Integer, String>
{
@Override
protected String doInBackground(String... params)
{
return params[0];
}
@Override
protected void onPostExecute(String result)
{
super.onPostExecute(result);
String [] finalMessage=result.split(":");
cv_pushToContentProvider = new ContentValues();
cv_pushToContentProvider.put("key",globalClock);
if(finalMessage.length > 2)
{
TextView tv = (TextView) findViewById(R.id.textView1);
tv.append("\n"+finalMessage[2]);
cv_pushToContentProvider.put("value", finalMessage[2]);
Toast.makeText(getApplicationContext(), finalMessage[2],Toast.LENGTH_SHORT).show();
}
else
{
TextView tv = (TextView) findViewById(R.id.textView1);
tv.append("\n"+result);
cv_pushToContentProvider.put("value", result);
Toast.makeText(getApplicationContext(), result,Toast.LENGTH_SHORT).show();
}
mContentResolver.insert(mUri, cv_pushToContentProvider);
}
}
public void sendMessage(View v)
{
String send_ClientMessage;
EditText ed=(EditText)findViewById(R.id.editText1);
send_ClientMessage=ed.getText().toString();
if(send_ClientMessage == null || send_ClientMessage == "")
return;
String sender=null;
if(emulator_instance == 5554)
{
long random_key = UUID.randomUUID().getLeastSignificantBits();
sender="avd0"+":"+sequenceNumberLocalApp+":"+send_ClientMessage+","+random_key;
sequenceNumberLocalApp++;
}
else if(emulator_instance == 5556)
{
long random_key = UUID.randomUUID().getLeastSignificantBits();
sender="avd1"+":"+sequenceNumberLocalApp+":"+send_ClientMessage+","+random_key;
sequenceNumberLocalApp++;
}
else if(emulator_instance == 5558)
{
long random_key = UUID.randomUUID().getLeastSignificantBits();
sender="avd2"+":"+sequenceNumberLocalApp+":"+send_ClientMessage+","+random_key;
sequenceNumberLocalApp++;
}
multiCastMessage(sender);
ed.setText(null);
}
public void testOne(View v)
{
//System.out.println("In test One");
new Thread(new Runnable()
{
public void run()
{
for(int i=0;i<5;i++)
{
//System.out.println("Sending Message");
long random_key = UUID.randomUUID().getLeastSignificantBits();
String s=null;
if(emulator_instance == 5554)
{
s="avd0"+":"+sequenceNumberLocalApp+","+random_key;
sequenceNumberLocalApp++;
}
else if(emulator_instance == 5556)
{
s="avd1"+":"+sequenceNumberLocalApp+","+random_key;
sequenceNumberLocalApp++;
}
else if(emulator_instance == 5558)
{
s="avd2"+":"+sequenceNumberLocalApp+","+random_key;
sequenceNumberLocalApp++;
}
multiCastMessage(s);
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
}
public void testTwo(View v)
{
test2=true;
String s=null;
if(emulator_instance == 5554)
{
long random_key = UUID.randomUUID().getLeastSignificantBits();
s="avd0"+":"+sequenceNumberLocalApp+","+random_key+","+"test2"+","+"pass";;
sequenceNumberLocalApp++;
}
else if(emulator_instance == 5556)
{
long random_key = UUID.randomUUID().getLeastSignificantBits();
s="avd1"+":"+sequenceNumberLocalApp+","+random_key+","+"test2"+","+"pass";;
sequenceNumberLocalApp++;
}
else if(emulator_instance == 5558)
{
long random_key = UUID.randomUUID().getLeastSignificantBits();
s="avd2"+":"+sequenceNumberLocalApp+","+random_key+","+"test2"+","+"pass";;
sequenceNumberLocalApp++;
}
multiCastMessage(s);
}
private void testCaseMultiCastMessage()
{
for(int i=1;i<3;i++)
{
long random_key = UUID.randomUUID().getLeastSignificantBits();
String s1=null;
if(emulator_instance == 5554)
{
s1="avd0"+":"+sequenceNumberLocalApp+","+random_key;
sequenceNumberLocalApp++;
}
else if(emulator_instance == 5556)
{
s1="avd1"+":"+sequenceNumberLocalApp+","+random_key;
sequenceNumberLocalApp++;
}
else if(emulator_instance == 5558)
{
s1="avd2"+":"+sequenceNumberLocalApp+","+random_key;
sequenceNumberLocalApp++;
}
multiCastMessage(s1);
}
}
private void multiCastMessage(final String message)
{
new Thread(new Runnable()
{
public void run()
{
Socket s=null;
try {
s=new Socket(localHost,11112);
sendandUpdate(s,message);
s.close();
s=null;
s=new Socket(localHost,11116);
sendandUpdate(s,message);
s.close();
s=null;
s=new Socket(localHost,11108);
sendandUpdate(s,message);
s.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
private void sendandUpdate(Socket s, String message) throws IOException
{
PrintWriter pw = new PrintWriter(s.getOutputStream());
pw.println(message);
pw.close();
s.close();
}
}