使用 HttpClient 的致命异常错误

Question

我想使用 JSON 并从网络获取数据。我找到了一个教程，然后应用了任何东西。结果令人沮丧。简要地说：

FATAL EXCEPTION: AsyncTask #1
java.lang.RuntimeException: An error occurred while executing doInBackground()

这是我的代码：

package com.example.winsekiz.searchlist;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.TextView;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;

public class WebServer extends Activity {


    final static String URI = "www.hocaogluticaret.com/a.html";
    TextView tvData;
    JSONObject json;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.turkey);
        tvData = (TextView) findViewById(R.id.tv);
        new Game().execute("text");
    }

    protected JSONObject readGameParks() throws ClientProtocolException, IOException, JSONException{

        HttpClient client = new DefaultHttpClient();
        HttpGet get = new HttpGet(URI);
        HttpResponse response =client.execute(get);
        StatusLine status = response.getStatusLine();
        int s = status.getStatusCode();

        if(s == 200) {

            HttpEntity e = response.getEntity();
            String data = EntityUtils.toString(e);
            JSONArray posts = new JSONArray(data);
            JSONObject last = posts.getJSONObject(0);
        }

        return  null;
    }

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

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

            try{
                json = readGameParks();
                String data = json.getString(params[0]);
                return  data;
            }

            catch (ClientProtocolException e) {
                e.printStackTrace();
            }

            catch (IOException e) {
                e.printStackTrace();
            }

            catch (JSONException e) {
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onPostExecute(String data){
            tvData.setText(data);
        }
    }
}

这是错误：

03-21 22:29:17.110 10922-10922/com.example.winsekiz.searchlist I/art: Not late-enabling -Xcheck:jni (already on)
03-21 22:29:17.120 10922-10922/com.example.winsekiz.searchlist W/System: ClassLoader referenced unknown path: /data/app/com.example.winsekiz.searchlist-2/lib/x86_64
03-21 22:29:17.130 10922-10935/com.example.winsekiz.searchlist D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
03-21 22:29:17.200 10922-10935/com.example.winsekiz.searchlist I/OpenGLRenderer: Initialized EGL, version 1.4
03-21 22:29:17.270 10922-10935/com.example.winsekiz.searchlist W/EGL_emulation: eglSurfaceAttrib not implemented
03-21 22:29:17.270 10922-10935/com.example.winsekiz.searchlist W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0x7feb1eea0e40, error=EGL_SUCCESS
03-21 22:29:18.910 10922-10944/com.example.winsekiz.searchlist E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
                                                                                 Process: com.example.winsekiz.searchlist, PID: 10922
                                                                                 java.lang.RuntimeException: An error occurred while executing doInBackground()
                                                                                     at android.os.AsyncTask.done(AsyncTask.java:309)
                                                                                     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
                                                                                     at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
                                                                                     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
                                                                                     at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:234)
                                                                                     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
                                                                                     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
                                                                                     at java.lang.Thread.run(Thread.java:818)
                                                                                  Caused by: java.lang.IllegalStateException: Target host must not be null, or set in parameters. scheme=null, host=null, path=www.hocaogluticaret.com/a.html
                                                                                     at org.apache.http.impl.client.DefaultRequestDirector.determineRoute(DefaultRequestDirector.java:603)
                                                                                     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:299)
                                                                                     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:560)
                                                                                     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:492)
                                                                                     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:470)
                                                                                     at com.example.winsekiz.searchlist.WebServer.readGameParks(WebServer.java:47)
                                                                                     at com.example.winsekiz.searchlist.WebServer$Game.doInBackground(WebServer.java:68)
                                                                                     at com.example.winsekiz.searchlist.WebServer$Game.doInBackground(WebServer.java:62)
                                                                                     at android.os.AsyncTask.call(AsyncTask.java:295)
                                                                                     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
                                                                                     at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:234) 
                                                                                     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113) 
                                                                                     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588) 
                                                                                     at java.lang.Thread.run(Thread.java:818) 
03-21 22:29:18.990 10922-10935/com.example.winsekiz.searchlist W/EGL_emulation: eglSurfaceAttrib not implemented
03-21 22:29:18.990 10922-10935/com.example.winsekiz.searchlist W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0x7feb1d9ff2c0, error=EGL_SUCCESS
03-21 22:29:19.010 10922-10935/com.example.winsekiz.searchlist E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7feb2e2daa90
03-21 22:29:24.090 10922-10935/com.example.winsekiz.searchlist E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7feb2e2daf60
03-21 22:34:18.920 10922-10944/? I/Process: Sending signal. PID: 10922 SIG: 9

Answer 1

您的 url 不完整。

www.hocaogluticaret.com/a.html

应该是

http://www.hocaogluticaret.com/a.html

或

https://www.hocaogluticaret.com/a.html

Answer 2

让我们单步执行代码

1) 启动 AsyncTask

new Game().execute("text");

2) 转到 doInBackground

json = readGameParks();

3) 连接到非限定 URI

HttpGet get = new HttpGet("www.hocaogluticaret.com/a.html");

你得到一个错误，解决这个问题把 http:// 放在地址前面。

4) 假设连接正确，继续 return null;

String data = json.getString(params[0]);
return  data;

在这里，params[0] 是 "text"，但是 json 是 null，因此抛出一个 NullPointerException。

要修复，请尝试不在 readGameParks 中返回 null。我认为您应该在状态代码检查中执行 return last; 。

在代码中，

JSONObject last = new JSONObject();

if(s == 200) {
    HttpEntity e = response.getEntity();
    String data = EntityUtils.toString(e);
    JSONArray posts = new JSONArray(data);
    last = posts.getJSONObject(0);
}

return last;

使用 HttpClient 的致命异常错误

FATAL EXCEPTION Error using HttpClient

java

android

json

exception

httpclient