java - 在 android.os.AsyncTask$3.done(AsyncTask.java :300)

Question

我的 Android java 代码有问题。我将发送一个 httpsRequest，然后返回一个 JSON 文件。但我收到错误，但我不知道为什么。我希望你能帮助我。

这是我得到的 LogCat:

05-27 10:14:34.779: E/AndroidRuntime(24498): java.lang.RuntimeException: An error occured while executing doInBackground()
05-27 10:14:34.779: E/AndroidRuntime(24498):    at android.os.AsyncTask$3.done(AsyncTask.java:300)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at java.util.concurrent.FutureTask.run(FutureTask.java:242)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at java.lang.Thread.run(Thread.java:818)
05-27 10:14:34.779: E/AndroidRuntime(24498): Caused by: java.lang.IllegalArgumentException: HostnameVerifier is null
05-27 10:14:34.779: E/AndroidRuntime(24498):    at javax.net.ssl.HttpsURLConnection.setDefaultHostnameVerifier(HttpsURLConnection.java:128)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at com.example.test.JSONTaskRegistrieren.doInBackground(JSONTaskRegistrieren.java:33)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at com.example.test.JSONTaskRegistrieren.doInBackground(JSONTaskRegistrieren.java:1)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at android.os.AsyncTask$2.call(AsyncTask.java:288)
05-27 10:14:34.779: E/AndroidRuntime(24498):    at java.util.concurrent.FutureTask.run(FutureTask.java:237)
05-27 10:14:34.779: E/AndroidRuntime(24498):    ... 4 more

我的代码是

package com.example.test;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;

import org.json.JSONException;
import org.json.JSONObject;

import android.os.AsyncTask;

public class JSONTaskRegistrieren extends AsyncTask<String, String, String>{

    private static final HostnameVerifier HostnameVerifier = null;

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

        String Servicepass;
        String SecretToken;

        BufferedReader reader = null;
        URL url;

        try{
            url = new URL(params[0]);
            HttpsURLConnection.setDefaultHostnameVerifier(HostnameVerifier); 
            new NullHostnameVerifier();
            HttpsURLConnection con = (HttpsURLConnection)url.openConnection();

            con.setRequestMethod("GET");
            con.setRequestProperty("Accept",  "application/json");

            con.setRequestProperty("WWSVC-REQID",  "1");

            InputStream stream = con.getInputStream();
            reader = new BufferedReader(new InputStreamReader(stream));
            StringBuffer buffer = new StringBuffer();
            String output;

            while ((output = reader.readLine()) != null){
                buffer.append(output);
            }

            String finalJson = buffer.toString();
            //System.out.println(buffer.toString());

            JSONObject parentObject = new JSONObject(finalJson);
            JSONObject servicepassobjekt = parentObject.getJSONObject("SERVICEPASS");

            //System.out.println(servicepassobjekt.toString());
            StringBuffer finalBufferedData = new StringBuffer();

                JSONObject finalObject = servicepassobjekt;

                Servicepass = finalObject.getString("PASSID");
                SecretToken = finalObject.getString("APPID");

                return finalBufferedData.toString();

    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (JSONException e) {
        e.printStackTrace();
    }
        return null;
    }

        @Override
        protected void onPostExecute(String result){
            super.onPostExecute(result);
            System.out.println(result);
        }

}

这是我开始请求的主类:

package com.example.test;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;

import javax.net.ssl.HttpsURLConnection;

import org.json.JSONArray;
import org.json.JSONObject;

import com.google.gson.Gson;
import com.google.gson.JsonObject;

import android.app.Activity;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;


public class MainActivity extends Activity {

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

        Button button1 = (Button) findViewById(R.id.button1);

            button1.setOnClickListener(new View.OnClickListener() {
                @SuppressWarnings("unused")
                public void onClick(View v) {
                    // ServiceURL
                    String ServiceURL = "https://192.168.0.64";

                    // Hersteller Hash
                    String HHash = "fa9b0dec3776ba123eba3049ec9f398h754";

                    // AppHash
                    String HAHash = "d20439ab3eabf9ebc3fae2c89b4869ai967";

                    // AppID
                    int AppID = 1;


                    new JSONTaskRegistrieren().execute(ServiceURL + "/WWSVC/WWSERVICE/REGISTER/"+HHash+"/"+HAHash+"/"+AppID+"/");
                }});    
    }

}

非常感谢您的帮助。

Answer 1

要查找的部分是堆栈跟踪的最后一个 Caused by: 部分。在您的情况下， IllegalArgumentException: HostnameVerifier is null 这是由您的代码 at com.example.test.JSONTaskRegistrieren.doInBackground(JSONTaskRegistrieren.java:33) 引起的(这是第一个提及您的代码的行)

从中您应该发现有问题的代码行是

HttpsURLConnection.setDefaultHostnameVerifier(HostnameVerifier); 

并且 HostnameVerifier 变量在该时间点的状态为 null。当您检查该变量的赋值发生位置时，您会发现唯一一次向它赋值是在初始化时。

private static final HostnameVerifier HostnameVerifier = null;

将其更改为

private static final HostnameVerifier HostnameVerifier = new NullHostnameVerifier();

并删除执行new NullHostnameVerifier();的行。它正在创建一个 validator 并立即将其丢弃，因为它没有存储在变量中。