我正在建立TCP多重通信，并希望从每个服务器获取所有响应的消息。实际方法是什么？
我尝试发送ip数组4个项目。在日志猫上，显示4次“添加新项”，但在onPostExecute上显示“完成::”，有时显示4次或3次与“添加新项”的数量不匹配。
MultiReadingWiFiModule.class
public class MultiReadingWiFiModule extends AsyncTask<String, Integer, List<AirItem>>{
private List<AirItem> items;
private String[] ipList;
private OnReadingResult result;
private static final int CONNECT_TIMEOUT = 1000;
private static final int RESPONSE_TIMEOUT = 1000;
private static final int DATA_SIZE = 7;
private static final String TAG = "Reading";
public MultiReadingWiFiModule(String[]ipList){
this.ipList = ipList;
}
public void startReading(){
this.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR);
}
public void setOnReadingResult(OnReadingResult result){
this.result = result;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
Log.w(TAG, "Start reading IP list :: "+ Arrays.toString(ipList));
items = new ArrayList<>(); //Initial air items
}
@Override
protected List<AirItem> doInBackground(String... strings) {
// Start Threads which read WiFi module from ip list
Thread[] scanThreads = new Thread[ipList.length];
for (int i=0; i<scanThreads.length; i++){
scanThreads[i] = startIPScanThread(ipList[i]);
}
// Wait for threads to finish
Log.w(TAG, "Waiting for Threads...");
int count = 0;
for (Thread t : scanThreads){
try {
if (t != null){
t.join();
}
}catch (InterruptedException e){
e.printStackTrace();
}
count++; //Count ip test finish
publishProgress(count*100/ipList.length); //Update progress
}
// Short pause seems to be necessary for ARP cache to update
// More: https://en.wikipedia.org/wiki/ARP_cache
Log.w(TAG, "Threads finished. "+count);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return items;
}
@Override
protected void onPostExecute(List<AirItem> items) {
super.onPostExecute(items);
for (AirItem i : items){
Log.w(TAG, "Finish :: "+i.getIp());
}
if (result!=null){
result.onFinish(items);
}
}
private Thread startIPScanThread(final String host){
final Thread t = new Thread(new Runnable() {
@Override
public void run() {
//Declare result object
Log.w(TAG, "Try connect "+host);
try {
Socket socket = new Socket();
socket.connect(new InetSocketAddress(host, Constant.PORT), CONNECT_TIMEOUT);
// Create PrintWriter object for sending messages to server.
PrintWriter outWrite = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
//Send message
outWrite.print(Constant.SCAN_INFO+","); //Request status
outWrite.flush();
Log.w(TAG, "Send request success!");
//Create object for receiving message response from server.
InputStreamReader inputStream = new InputStreamReader(socket.getInputStream());
//Read response message
StringBuilder s = new StringBuilder("");
int i=0; String[]buffer = new String[Constant.BUFF_MAX];
long start = System.currentTimeMillis(); boolean timeout = false;
while (!timeout){
timeout = !((System.currentTimeMillis() - start)<RESPONSE_TIMEOUT);
//Convert int to char
char data = (char)inputStream.read();
//Check syntax ',' mean ending each word. So Server must send Ex: Hello,You
if (data==','){
buffer[i] = s.toString(); ///Add message to String array
s = new StringBuilder(""); ///Clear string
i++;
}else {
s.append(data); //Create word string
}
//Check InputSteam read finish
if (!inputStream.ready()) {
buffer = i > 0 ? Arrays.copyOf(buffer, i) : new String[]{s.toString()}; //Re-size buffer
Log.w(TAG, "Server response :: " + Arrays.toString(buffer));
if (buffer.length >= DATA_SIZE) {
Log.w(TAG, "Add new item");
//Show only read success
items.add(new AirItem(host, buffer[0], buffer[1], buffer[2], buffer[4], buffer[5], buffer[6], buffer[9]));
}
break; //Out of loop
}
}
socket.close(); //Disconnect server
} catch (IOException e) {
e.printStackTrace();
}
}
});
t.start();
return t;
}
interface OnReadingResult{
void onFinish(List<AirItem> itemsSuccess);
}
}
在日志猫上
12-25 18:49:21.619 18842-18842/com.apyeng.tasakicentral W/Reading: Start
reading IP list :: [192.168.1.204, 192.168.1.202, 192.168.1.205, 192.168.1.203]
12-25 18:49:21.630 18842-21156/com.apyeng.tasakicentral W/Reading: Waiting for Threads...
12-25 18:49:21.957 18842-21159/com.apyeng.tasakicentral W/Reading: Add new item :: 192.168.1.205
12-25 18:49:21.959 18842-21157/com.apyeng.tasakicentral W/Reading: Add new item :: 192.168.1.204
12-25 18:49:21.960 18842-21158/com.apyeng.tasakicentral W/Reading: Add new item :: 192.168.1.202
12-25 18:49:21.962 18842-21160/com.apyeng.tasakicentral W/Reading: Add new item :: 192.168.1.203
12-25 18:49:21.963 18842-21156/com.apyeng.tasakicentral W/Reading: Threads finished. 4
12-25 18:49:22.966 18842-18842/com.apyeng.tasakicentral W/Reading:
Finish :: 192.168.1.205
Finish :: 192.168.1.204
Finish :: 192.168.1.202
Finish :: 192.168.1.203
12-25 18:49:31.278 18842-18842/com.apyeng.tasakicentral W/Reading: Start reading IP list :: [192.168.1.203, 192.168.1.205, 192.168.1.202, 192.168.1.204]
12-25 18:49:31.291 18842-21448/com.apyeng.tasakicentral W/Reading: Waiting for Threads...
12-25 18:49:31.598 18842-21449/com.apyeng.tasakicentral W/Reading: Add new item :: 192.168.1.203
12-25 18:49:31.598 18842-21452/com.apyeng.tasakicentral W/Reading: Add new item :: 192.168.1.204
12-25 18:49:31.600 18842-21450/com.apyeng.tasakicentral W/Reading: Add new item :: 192.168.1.205
12-25 18:49:31.606 18842-21451/com.apyeng.tasakicentral W/Reading: Add new item :: 192.168.1.202
12-25 18:49:31.607 18842-21448/com.apyeng.tasakicentral W/Reading: Threads finished. 4
12-25 18:49:32.609 18842-18842/com.apyeng.tasakicentral W/Reading: Finish :: 192.168.1.203
Finish :: 192.168.1.205
Finish :: 192.168.1.202
答案 0 :(得分：0)
执行此任务的一种方法是用向量替换ArrayList，因为向量是线程安全的向量。
尝试下面的代码，我创建了一个同步函数，用于向List中添加项目（如果不使用向量，这是另一种选择）
public class MultiReadingWiFiModule extends AsyncTask<String, Integer, List<AirItem>>{
private List<AirItem> items;
private String[] ipList;
private OnReadingResult result;
private static final int CONNECT_TIMEOUT = 1000;
private static final int RESPONSE_TIMEOUT = 1000;
private static final int DATA_SIZE = 7;
private static final String TAG = "Reading";
public MultiReadingWiFiModule(String[]ipList){
this.ipList = ipList;
}
public void startReading(){
this.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR);
}
public void setOnReadingResult(OnReadingResult result){
this.result = result;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
Log.w(TAG, "Start reading IP list :: "+
Arrays.toString(ipList));
items = new ArrayList<>(); //Initial air items
}
@Override
protected List<AirItem> doInBackground(String... strings) {
// Start Threads which read WiFi module from ip list
Thread[] scanThreads = new Thread[ipList.length];
for (int i=0; i<scanThreads.length; i++){
scanThreads[i] = startIPScanThread(ipList[i]);
}
// Wait for threads to finish
Log.w(TAG, "Waiting for Threads...");
int count = 0;
for (Thread t : scanThreads){
try {
if (t != null){
t.join();
}
}catch (InterruptedException e){
e.printStackTrace();
}
count++; //Count ip test finish
publishProgress(count*100/ipList.length); //Update progress
}
// Short pause seems to be necessary for ARP cache to update
// More: https://en.wikipedia.org/wiki/ARP_cache
Log.w(TAG, "Threads finished. "+count);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return items;
}
@Override
protected void onPostExecute(List<AirItem> items) {
super.onPostExecute(items);
for (AirItem i : items){
Log.w(TAG, "Finish :: "+i.getIp());
}
if (result!=null){
result.onFinish(items);
}
}
private Thread startIPScanThread(final String host){
final Thread t = new Thread(new Runnable() {
@Override
public void run() {
//Declare result object
Log.w(TAG, "Try connect "+host);
try {
Socket socket = new Socket();
socket.connect(new InetSocketAddress(host, Constant.PORT), CONNECT_TIMEOUT);
// Create PrintWriter object for sending messages to server.
PrintWriter outWrite = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
//Send message
outWrite.print(Constant.SCAN_INFO+","); //Request status
outWrite.flush();
Log.w(TAG, "Send request success!");
//Create object for receiving message response from server.
InputStreamReader inputStream = new InputStreamReader(socket.getInputStream());
//Read response message
StringBuilder s = new StringBuilder("");
int i=0; String[]buffer = new String[Constant.BUFF_MAX];
long start = System.currentTimeMillis(); boolean timeout = false;
while (!timeout){
timeout = !((System.currentTimeMillis() - start)<RESPONSE_TIMEOUT);
//Convert int to char
char data = (char)inputStream.read();
//Check syntax ',' mean ending each word. So Server must send Ex: Hello,You
if (data==','){
buffer[i] = s.toString(); ///Add message to String array
s = new StringBuilder(""); ///Clear string
i++;
}else {
s.append(data); //Create word string
}
//Check InputSteam read finish
if (!inputStream.ready()) {
buffer = i > 0 ? Arrays.copyOf(buffer, i) : new String[]{s.toString()}; //Re-size buffer
Log.w(TAG, "Server response :: " + Arrays.toString(buffer));
if (buffer.length >= DATA_SIZE) {
Log.w(TAG, "Add new item");
//Show only read success
AirItemAdd(host, buffer[0], buffer[1], buffer[2], buffer[4], buffer[5], buffer[6], buffer[9]));
}
break; //Out of loop
}
}
socket.close(); //Disconnect server
} catch (IOException e) {
e.printStackTrace();
}
}
});
t.start();
return t;
}
interface OnReadingResult{
void onFinish(List<AirItem> itemsSuccess);
}
public synchronized void AirItemAdd(String... buffer){
items.add(new AirItem(buffer[0], buffer[1], buffer[2], buffer[4], buffer[5], buffer[6], buffer[9],buffer[10] ));
}
}