我在Java中遇到异步任务问题:
我有一个移动应用程序,该应用程序将图像发送到我的服务器,然后从该服务器接收另一个图像,然后通过套接字/端口接收0到100之间的7个int值。所以我有一个AsnycTask,我在其中执行DoInBackground方法中的所有连接/发送/接收操作。图像工作正常,但是问题是int []:我有一个长度为7的probabilities [] int数组,在其中放置接收到的值(在DoInBackground中)。然后,在onPostExecute中,我调用需要这些值的我自己的函数。
现在的问题是:有时这些值在那里,有时Array仍然只有0(而且我可以肯定的是数据不仅是0)。
这是我的AsnyTask代码
class ConnectTask extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... voids) {
try {
//Connect to my PC and send my image from my phone
Socket photoSocket = new Socket(IP_ADDRESS, PORT_NO);
DataOutputStream dos = new DataOutputStream(photoSocket.getOutputStream());
FileInputStream fis = new FileInputStream(pathname);
int size = fis.available();
byte[] data = new byte[size];
fis.read(data);
dos.write(data);
dos.flush();
fis.close();
dos.close();
photoSocket.close();
//now receive the other image from server
ServerSocket serverSocket = new ServerSocket(1235);
Socket incomingSocket = serverSocket.accept();
InputStream is = incomingSocket.getInputStream();
FileOutputStream fos = new FileOutputStream(Environment.getExternalStorageDirectory() + "/image_from_server.jpg");
BufferedOutputStream bos = new BufferedOutputStream(fos);
byte[] aByte = new byte[40000];
int bytesRead;
while ((bytesRead = is.read(aByte)) != -1) {
bos.write(aByte, 0, bytesRead);
}
is.close();
fos.close();
bos.close();
serverSocket.close();
incomingSocket.close();
//now Receive Values (ints)
ServerSocket serverSocket2 = new ServerSocket(1236);
Socket incomingSocket2 = serverSocket2.accept();
InputStream inputstream = incomingSocket2.getInputStream();
byte[] data2 = new byte[7];
inputstream.read(data2);
//Fill array with received ints THIS IS SOMETIMES WORKING, SOMETIMES probabilities[] STAYS FILLED WITH 0s
for (int i = 0; i < data2.length; i++){
probabilities[i] = data2[i];
}
serverSocket2.close();
incomingSocket2.close();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPreExecute() {
//irrelevant
}
@Override
protected void onPostExecute(Void aVoid) {
File xaifile = new File(Environment.getExternalStorageDirectory() + "/image_from_server.jpg");
//...doing some UI stuff
//..................
//..................
//now call function where i replace picture. Since this is in the "postExecute" method, my probabilities[] should have been filled with data since its in the doInBackground method.
replacePicture(xaifile);
}
}
ConnectTask connect = new ConnectTask();
Void[] param = null;
//execute Async task
connect.execute(param);
最佳答案
inputstream.read(data2)可能返回-1,这意味着不读取任何字节并且data2保持为零,因此如果读取返回-1,则进行处理并重试。
关于java - Java异步任务/套接字连接问题,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/62898497/