我正在尝试使用Android中的HttpURLConnection从url读取数据。我从here中引用了。我遵循相同的方法，但出现错误java.net.UnknownHostException：无法解析主机“ thehindu.com”：与主机名无关联的地址。我已启用所有权限。我的主要活动代码是
package com.example.urlconnect;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import android.Manifest;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
public class MainActivity extends AppCompatActivity {
public static final int REQUEST_ID_MULTIPLE_PERMISSIONS=1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
checkAndRequestPermissions();
new connection().execute();
}
private boolean checkAndRequestPermissions() {
int permissionInternet = ContextCompat.checkSelfPermission(this,
android.Manifest.permission.INTERNET);
int permissionCamera = ContextCompat.checkSelfPermission(this,
android.Manifest.permission.CAMERA);
int readPhoneState = ContextCompat.checkSelfPermission(this,
android.Manifest.permission.READ_EXTERNAL_STORAGE);
int readPhoneState_tm = ContextCompat.checkSelfPermission(this,
android.Manifest.permission.READ_PHONE_STATE);
int writePhoneState = ContextCompat.checkSelfPermission(this,
android.Manifest.permission.WRITE_EXTERNAL_STORAGE);
int coarseLocation = ContextCompat.checkSelfPermission(this,
android.Manifest.permission.ACCESS_COARSE_LOCATION);
int readSMS = ContextCompat.checkSelfPermission(this,
android.Manifest.permission.READ_SMS);
int locationPermission = ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION);
List<String> listPermissionsNeeded = new ArrayList<>();
if (permissionInternet != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(Manifest.permission.INTERNET);
}if (locationPermission != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(android.Manifest.permission.ACCESS_FINE_LOCATION);
}
if (permissionCamera != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(android.Manifest.permission.CAMERA);
}
if (readSMS != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(android.Manifest.permission.READ_SMS);
}
if (readPhoneState != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(android.Manifest.permission.READ_EXTERNAL_STORAGE);
}
if (writePhoneState != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(android.Manifest.permission.WRITE_EXTERNAL_STORAGE);
}
if (coarseLocation != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(android.Manifest.permission.ACCESS_COARSE_LOCATION);
}
if (readPhoneState_tm != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(android.Manifest.permission.READ_PHONE_STATE);
}
if (!listPermissionsNeeded.isEmpty()) {
ActivityCompat.requestPermissions(this, listPermissionsNeeded.toArray(new String[listPermissionsNeeded.size()]), REQUEST_ID_MULTIPLE_PERMISSIONS);
return false;
}
return true;
}
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
//Log.d("test1", "Permission callback called-------");
switch (requestCode) {
case REQUEST_ID_MULTIPLE_PERMISSIONS: {
Map<String, Integer> perms = new HashMap<>();
// Initialize the map with both permissions
perms.put(android.Manifest.permission.INTERNET, PackageManager.PERMISSION_GRANTED);
perms.put(android.Manifest.permission.READ_EXTERNAL_STORAGE, PackageManager.PERMISSION_GRANTED);
perms.put(android.Manifest.permission.ACCESS_FINE_LOCATION, PackageManager.PERMISSION_GRANTED);
perms.put(android.Manifest.permission.CAMERA, PackageManager.PERMISSION_GRANTED);
perms.put(android.Manifest.permission.WRITE_EXTERNAL_STORAGE, PackageManager.PERMISSION_GRANTED);
perms.put(android.Manifest.permission.ACCESS_COARSE_LOCATION, PackageManager.PERMISSION_GRANTED);
perms.put(android.Manifest.permission.READ_PHONE_STATE, PackageManager.PERMISSION_GRANTED);
perms.put(android.Manifest.permission.READ_SMS, PackageManager.PERMISSION_GRANTED);
// Fill with actual results from user
if (grantResults.length > 0) {
for (int i = 0; i < permissions.length; i++) {
perms.put(permissions[i], grantResults[i]);
//Log.d("permissions..",""+permissions[i]);
//Log.d("grant..",""+grantResults[i]);
}
// Check for both permissions
if (perms.get(Manifest.permission.INTERNET) == PackageManager.PERMISSION_GRANTED && perms.get(android.Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED &&
perms.get(android.Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED
&& perms.get(android.Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED &&
perms.get(android.Manifest.permission.READ_SMS) == PackageManager.PERMISSION_GRANTED
&& perms.get(android.Manifest.permission.READ_PHONE_STATE) == PackageManager.PERMISSION_GRANTED &&
perms.get(android.Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED
&& perms.get(android.Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
//Log.d("test2", "sms & location services permission granted");
// process the normal flow
//else any one or both the permissions are not granted
} else {
// Log.d("test3", "Some permissions are not granted ask again ");
if (ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.permission.CAMERA) || ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.permission.ACCESS_FINE_LOCATION) || ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) || ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.permission.READ_EXTERNAL_STORAGE) || ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.permission.WRITE_EXTERNAL_STORAGE) || ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.permission.READ_PHONE_STATE) ||ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.permission.READ_SMS)) {
showDialogOK("SMS and Location Services Permission required for this app",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
switch (which) {
case DialogInterface.BUTTON_POSITIVE:
checkAndRequestPermissions();
break;
case DialogInterface.BUTTON_NEGATIVE:
// proceed with logic by disabling the related features or quit the app.
break;
}
}
});
}
//permission is denied (and never ask again is checked)
//shouldShowRequestPermissionRationale will return false
else {
Toast.makeText(this, "Go to settings and enable permissions", Toast.LENGTH_LONG).show();
//proceed with logic by disabling the related features or quit the app.
}
}
}
}
}
}
private void showDialogOK(String message, DialogInterface.OnClickListener okListener) {
new AlertDialog.Builder(this)
.setMessage(message)
.setPositiveButton("OK", okListener)
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
finish();
}})
.create()
.show();
}
public class connection extends AsyncTask<Void, Void, Void> {
public static final String REQUEST_METHOD = "GET";
public static final int READ_TIMEOUT = 5000;
public static final int CONNECTION_TIMEOUT = 150000;
@Override
protected Void doInBackground(Void... voids) {
try {
URL RssUrl=new URL("https", "skymetweather.com", 80, "/");
Properties systemProperties = System.getProperties();
Log.d("ss4","yyyyy");
HttpURLConnection conn1=(HttpURLConnection) RssUrl.openConnection();
conn1.setRequestMethod(REQUEST_METHOD);
conn1.setReadTimeout(READ_TIMEOUT);
conn1.setConnectTimeout(CONNECTION_TIMEOUT);
Log.d("ss3","yyyyy"+systemProperties.getProperty("https.proxyPassword"));
conn1.connect();
Log.d("ss1",""+conn1.getResponseCode());
} catch (IOException e) {
Log.e("chand",""+e);
}
return null;
}
}
}
我的清单XML是
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:dist="http://schemas.android.com/apk/distribution"
package="com.example.urlconnect">
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_SMS"/>
<dist:module dist:instant="true" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
在<application>上，请将android:usesCleartextTraffic="true"设置为AndroidManifest.xml。并设置在里面
<uses-library
android:name="org.apache.http.legacy"
android:required="false" />