HttpURLConnection在Java中工作但不是android

时间：2016-03-05 18:34:11

标签： java android http

我们一直在尝试向Android应用中的node.js服务器发送POST请求。因为旧的apache依赖项已被弃用（我似乎无法访问它们 - 我已经尝试过了）我们一直在使用HttpURLConnection类。我们在java中编写了一个类，它只是一个独立的类（Request.java），但是当它在android程序中被编译时，它每次都会抛出一个错误，当它试图获取错误消息时，它只返回null。

Request.java 

package andrewmmattb.beacongame;

/**
 * Created by matt on 05/03/2016.
 */

import java.net.HttpURLConnection;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.URL;

public class Request {

    public static void main(String[] args) throws Exception {
        Request http = new Request();

        System.out.println("POST");
        http.sendPost("{\"username\": \"matt\",\"newPoints\":5}");
    }

    public static void sendPost(String json) throws Exception {

        String url = "http://ec2-54-187-69-193.us-west-2.compute.amazonaws.com/points";
        URL obj = new URL(url);
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();

        //add reuqest header
        con.setRequestMethod("POST");
        con.setRequestProperty("User-Agent", "");
        con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
        con.setRequestProperty("Content-Type", "application/json");

        String urlParameters = "";

        // Send post request
        con.setDoOutput(true);
        DataOutputStream wr = new      DataOutputStream(con.getOutputStream());
        wr.writeBytes(json);
        wr.flush();
        wr.close();

        int responseCode = con.getResponseCode();
        System.out.println("\nSending 'POST' request to URL : " + url);
        System.out.println("Post parameters : " + urlParameters);
        System.out.println("Response Code : " + responseCode);

        BufferedReader in = new BufferedReader(
                new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();

        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        //print result
        System.out.println(response.toString());
    }
}

GameActivity.java 

package andrewmmattb.beacongame;

import android.app.Activity;
import android.app.DownloadManager;
import android.content.Intent;
import android.os.Bundle;
import android.os.Debug;
import android.os.Handler;
import android.util.Base64;
import android.util.JsonWriter;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;

import org.json.*;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

public class GameActivity extends Activity {

String username;
String serverPath = "THE PATH TO THE SERVER";

int score = 0;
int prevScore = 0;

TextView usernameTextView;
TextView scoreTextView;

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

    usernameTextView = (TextView)findViewById(R.id.textViewGameUsername);
    scoreTextView = (TextView)findViewById(R.id.textViewGameScore);

    Intent intent = getIntent();
    username = intent.getStringExtra("username");
    usernameTextView.setText(username);

    try {
        makeSeverPost();
    }
    catch (IOException e) {
        Toast.makeText(GameActivity.this,"There was an IO error, called after function call (line 56)",Toast.LENGTH_LONG).show();
        e.printStackTrace();
    }
}

void makeSeverPost() throws IOException {
    // creates a map object with username and the additional points to the previous sent score
    Map<String,Object> values = new HashMap<String,Object>();
    values.put("username",username);
    values.put("newPoints",score-prevScore);
    // sets the previous score to equal the current score
    prevScore = score;

    // writes the map into a string in JSON format
    String jsonString = new JSONObject(values).toString();

    try {
        Request.sendPost(jsonString);
    } catch (Exception e) {
        e.printStackTrace();
        Log.e("problem",""+e.getMessage());
    }
    }
}

由于我们所做的所有其他尝试都有许多冗余的依赖性。

2 个答案:

答案 0 :(得分：4)

在主线程的android网络中是不允许的。

您必须从AsyncTask。

调用此方法

示例：

class MakeSeverPostTask extends AsyncTask<Void, String, JSONObject>
{
    Map<String,Object> params;

    public MakeSeverPostTask(Map<String,Object> params){
      this.params = params;
    }

    protected JSONObject doInBackground(Void... v)
    {
        String jsonString = new JSONObject(this.params).toString();
        return Request.sendPost(jsonString);
    }

    protected void onPostExecute(JSONObject result)
    {

    }
}

用法：

Map<String,Object> values = new HashMap<String,Object>();
values.put("username",username);
values.put("newPoints",score-prevScore);

new MakeSeverPostTask(values).execute();

答案 1 :(得分：0)

这是更详细的解决方案：

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

        usernameTextView = (TextView)findViewById(R.id.textViewGameUsername);
        scoreTextView = (TextView)findViewById(R.id.textViewGameScore);

        // creates a map object with username and the additional points to the previous sent score
        Map<String,Object> values = new HashMap<String,Object>();
        values.put("username",username);
        values.put("newPoints",score-prevScore);

        // writes the map into a string in JSON format
        String jsonString = new JSONObject(values).toString();
        String url = "http://ec2-54-187-69-193.us-west-2.compute.amazonaws.com/points";

        // executing AsyncTask with passing string parameters.
        ServerAsyncTask makeServerPost = new ServerAsyncTask();

        makeServerPost.execute(url, jsonString);
    }

    private class ServerAsyncTask extends AsyncTask<String, Void, JSONObject> {

        private final String TAG = ServerAsyncTask.class.getSimpleName();

        @Override
        protected JSONObject doInBackground(String... params) {
            JSONObject result = null;
            try {
                URL obj = new URL(params[0]);                       // added url

                HttpURLConnection con = (HttpURLConnection) obj.openConnection();

                //add reuqest header
                con.setRequestMethod("POST");
                con.setRequestProperty("User-Agent", "");
                con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
                con.setRequestProperty("Content-Type", "application/json");

                String urlParameters = "";

                // Send post request
                con.setDoOutput(true);
                DataOutputStream wr = new DataOutputStream(con.getOutputStream());
                wr.writeBytes(params[1]);                       // Added json
                wr.flush();
                wr.close();

                int responseCode = con.getResponseCode();

                Log.i(TAG, "\nSending 'POST' request to URL : " + params[0]);
                Log.i(TAG, "Post parameters : " + urlParameters);
                Log.i(TAG, "Response Code : " + responseCode);

                // safer way to parse response
                if(responseCode == HttpURLConnection.HTTP_OK){

                    BufferedReader in = new BufferedReader(
                            new InputStreamReader(con.getInputStream()));
                    String inputLine;
                    StringBuilder response = new StringBuilder();

                    while ((inputLine = in.readLine()) != null) {
                        response.append(inputLine);
                    }
                    in.close();

                    // print result
                    Log.i(TAG, response.toString());

                    result = new JSONObject(response.toString());
                }

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

            return result;
        }

        @Override
        protected void onPostExecute(JSONObject jsonObject) {
            super.onPostExecute(jsonObject);
            /* You get response jsonObject here,
            you can now update your UI here*/

            // Example update your score.
            try {

                String score = (String) jsonObject.get("score");

                scoreTextView.setText(score);

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