我正在尝试使用 Java 中的套接字编写 TCP 客户端，但是我似乎无法读取从服务器发送到客户端的数据。有时我会从服务器收到，但不是所有时间..
public class TCPClient {
private String serverMessage;
public static final String SERVERIP = "103.13.97.87"; //your computer IP address
public static final int SERVERPORT = 8101;
private OnMessageReceived mMessageListener = null;
private boolean mRun = false;
PrintWriter out;
BufferedReader in;
/**
* Constructor of the class. OnMessagedReceived listens for the messages received from server
*/
public TCPClient(OnMessageReceived listener) {
mMessageListener = listener;
}
/**
* Sends the message entered by client to the server
* @param message text entered by client
*/
public void sendMessage(String message){
if (out != null && !out.checkError()) {
out.println(message);
out.flush();
}
}
public void stopClient(){
mRun = false;
}
public void run() {
mRun = true;
try {
//here you must put your computer's IP address.
InetAddress serverAddr = InetAddress.getByName(SERVERIP);
Log.e("TCP Client", "C: Connecting...");
//create a socket to make the connection with the server
Socket socket = new Socket(serverAddr, SERVERPORT);
try {
//send the message to the server
out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
Log.e("TCP Client", "C: Sent.");
Log.e("TCP Client", "C: Done.");
//receive the message which the server sends back
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
//in this while the client listens for the messages sent by the server
while (mRun) {
serverMessage = in.readLine();
if (serverMessage != null && mMessageListener != null) {
//call the method messageReceived from MyActivity class
mMessageListener.messageReceived(serverMessage);
}
serverMessage = null;
}
Log.e("RESPONSE FROM SERVER", "S: Received Message: '" + serverMessage + "'");
} catch (Exception e) {
Log.e("TCP", "S: Error", e);
} finally {
//the socket must be closed. It is not possible to reconnect to this socket
// after it is closed, which means a new socket instance has to be created.
socket.close();
}
} catch (Exception e) {
Log.e("TCP", "C: Error", e);
}
}
//Declare the interface. The method messageReceived(String message) will must be implemented in the MyActivity
//class at on asynckTask doInBackground
public interface OnMessageReceived {
public void messageReceived(String message);
}
}
我的 CustomAdapter.java
public class MyCustomAdapter extends BaseAdapter {
private ArrayList<String> mListItems;
private LayoutInflater mLayoutInflater;
public MyCustomAdapter(Context context, ArrayList<String> arrayList){
mListItems = arrayList;
//get the layout inflater
mLayoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
//getCount() represents how many items are in the list
return mListItems.size();
}
@Override
//get the data of an item from a specific position
//i represents the position of the item in the list
public Object getItem(int i) {
return null;
}
@Override
//get the position id of the item from the list
public long getItemId(int i) {
return 0;
}
@Override
public View getView(int position, View view, ViewGroup viewGroup) {
//check to see if the reused view is null or not, if is not null then reuse it
if (view == null) {
view = mLayoutInflater.inflate(R.layout.list_item, null);
}
//get the string item from the position "position" from array list to put it on the TextView
String stringItem = mListItems.get(position);
if (stringItem != null) {
TextView itemName = (TextView) view.findViewById(R.id.list_item_text_view);
if (itemName != null) {
//set the item name on the TextView
itemName.setText(stringItem);
}
}
//this method must return the view corresponding to the data at the specified position.
return view;
}
}
MainActivity.java
public class MainActivity extends Activity
{
private ListView mList;
private ArrayList<String> arrayList;
private MyCustomAdapter mAdapter;
private TCPClient mTcpClient;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
arrayList = new ArrayList<String>();
final EditText editText = (EditText) findViewById(R.id.editText);
Button send = (Button)findViewById(R.id.send_button);
//relate the listView from java to the one created in xml
mList = (ListView)findViewById(R.id.list);
mAdapter = new MyCustomAdapter(this, arrayList);
mList.setAdapter(mAdapter);
// connect to the server
new connectTask().execute("");
send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//String message = editText.getText().toString();
String message = "mall: ABC Mall date: 08/08/2013 time: 13:45 md5 f6151b2cdc256be4971bcc30629bbc7\r\n";
/* String str =md5Digest(message);
String s=message+str;*/
//add the text in the arrayList
arrayList.add("c: " + message);
//sends the message to the server
if (mTcpClient != null) {
mTcpClient.sendMessage(message);
/*mTcpClient.sendMessage(s);*/
}
//refresh the list
mAdapter.notifyDataSetChanged();
editText.setText("");
}
});
}
public class connectTask extends AsyncTask<String,String,TCPClient> {
@Override
protected TCPClient doInBackground(String... message) {
//we create a TCPClient object and
mTcpClient = new TCPClient(new TCPClient.OnMessageReceived() {
@Override
//here the messageReceived method is implemented
public void messageReceived(String message) {
//this method calls the onProgressUpdate
publishProgress(message);
}
});
mTcpClient.run();
return null;
}
@Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
//in the arrayList we add the messaged received from server
arrayList.add(values[0]);
// notify the adapter that the data set has changed. This means that new message received
// from server was added to the list
mAdapter.notifyDataSetChanged();
}
}
public static final String md5Digest(final String text)
{
try
{
// Create MD5 Hash
MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
digest.update(text.getBytes());
byte messageDigest[] = digest.digest();
// Create Hex String
StringBuffer hexString = new StringBuffer();
int messageDigestLenght = messageDigest.length;
for (int i = 0; i < messageDigestLenght; i++)
{
String hashedData = Integer.toHexString(0xFF & messageDigest[i]);
while (hashedData.length() < 2)
hashedData = "0" + hashedData;
hexString.append(hashedData);
}
return hexString.toString();
} catch (NoSuchAlgorithmException e)
{
e.printStackTrace();
}
return ""; // if text is null then return nothing
}
@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;
}
}