java - 无法使用异步任务复制程序中给出 URL 的网页的 html 代码。安卓工作室3.4.2

Question

我想使用异步任务使用并行线程下载网页的 HTML 内容。我从在线教程中学习了代码，我的代码与讲座中的代码完全一样，运行良好。

异步任务中的 try 命令不起作用，doInbackGround() 方法通过 catch 返回“失败”。

我已经在方法中打印了 URL 名称，并且它显示在日志中。

I have provided the internet permission also through AndroidManifest.xml.

My primary guess is following three lines are creating problem though I would appreciate expert advice.



   urlConnection=(HttpURLConnection) url.openConnection();

                    InputStream in=urlConnection.getInputStream();

                    InputStreamReader reader = new InputStreamReader(in);

package com.example.webdownload;

import androidx.appcompat.app.AppCompatActivity;

import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;


public class MainActivity extends AppCompatActivity {


    public class DownLoadTask extends AsyncTask<String,Void,String> {

            @Override
        protected String doInBackground(String... urls) {

            URL url;
            String result="";
            HttpURLConnection urlConnection=null;

            try{

                url=new URL(urls[0]);
                Log.i("String",urls[0]);  // this is getting printed

                urlConnection=(HttpURLConnection) url.openConnection();
                InputStream in=urlConnection.getInputStream();
                InputStreamReader reader = new InputStreamReader(in);

                int data=reader.read();
                Log.i("Data",Integer.toString(data)); //this is not getting
                                                         printed
                while (data!=-1)
                {
                    char current = (char) data;
                    result+=current;
                    data=reader.read();

                }

                return result;

            }catch(Exception e)
            {
                e.printStackTrace();
                return "Failed";
            }

        }
   }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        DownLoadTask task=new DownLoadTask();


        String result=null;
       try {
           result = task.execute("https://www.ecowebhosting.co.uk/").get();

       }catch (Exception e)
       {
         e.printStackTrace();
       }
        Log.i("Result",result);

        }
}

我无法在这里发布日志

Answer 1

Since I could not post logs in my question I am posting them here:

These are the logs between URL printing in logs and to the Failed return through the method

I/String: https://www.ecowebhosting.co.uk/
D/NetworkSecurityConfig: No Network Security Config specified, using platform default
W/System.err: java.net.SocketException: socket failed: EPERM (Operation not permitted)
W/System.err:     at java.net.Socket.createImpl(Socket.java:492)
W/System.err:     at java.net.Socket.getImpl(Socket.java:552)
W/System.err:     at java.net.Socket.setSoTimeout(Socket.java:1180)
W/System.err:     at com.android.okhttp.internal.io.RealConnection.connectSocket(RealConnection.java:143)
W/System.err:     at com.android.okhttp.internal.io.RealConnection.connect(RealConnection.java:116)
W/System.err:     at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:186)
W/System.err:     at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:128)
W/System.err:     at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:97)
W/System.err:     at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:289)
W/System.err:     at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:232)
W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:465)
W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:411)
W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:248)
W/System.err:     at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getInputStream(DelegatingHttpsURLConnection.java:211)
W/System.err:     at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:30)
W/System.err:     at com.example.webdownload.MainActivity$DownLoadTask.doInBackground(MainActivity.java:35)
        at com.example.webdownload.MainActivity$DownLoadTask.doInBackground(MainActivity.java:18)
W/System.err:     at android.os.AsyncTask$3.call(AsyncTask.java:378)
W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:266)
W/System.err:     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:289)
W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
W/System.err:     at java.lang.Thread.run(Thread.java:919)
I/Result: Failed
D