java - androidhive 教程中的 JSONParser，DefaultHttpClient 中的 NoSuchMethodError

Question

我正在关注 this教程，并收到此错误:

Caused by: java.lang.NoSuchMethodError: No virtual method execute(Lorg/apache/http/client/methods/HttpUriRequest;)Lorg/apache/http/client/methods/CloseableHttpResponse; in class Lorg/apache/http/impl/client/DefaultHttpClient; or its super classes (declaration of 'org.apache.http.impl.client.DefaultHttpClient' appears in /system/framework/ext.jar)
                at info.androidhive.materialtabs.adpater.JSONParser.makeHttpRequest(JSONParser.java:52)
                at info.androidhive.materialtabs.UserFunctions.loginUser(UserFunctions.java:37)
                at info.androidhive.materialtabs.activity.MainActivity$Login.doInBackground(MainActivity.java:551)
                at info.androidhive.materialtabs.activity.MainActivity$Login.doInBackground(MainActivity.java:519)

这是我正在使用的 JSONParser 类:

public class JSONParser {
     static InputStream is = null;
        static JSONObject jObj = null;
        static String json = "";
        // constructor
        public JSONParser() {
        }
        // function get json from url
        // by making HTTP POST or GET method
        public JSONObject makeHttpRequest(String url, String method,
                List<NameValuePair> params) {
            // Making HTTP request
            try {
                // check for request method
                if(method == "POST"){
                    // request method is POST
                    // defaultHttpClient
                    DefaultHttpClient httpClient = new DefaultHttpClient();
                    HttpPost httpPost = new HttpPost(url);
                    httpPost.setEntity(new UrlEncodedFormEntity(params));
                    HttpResponse httpResponse = httpClient.execute(httpPost);
                    HttpEntity httpEntity = httpResponse.getEntity();
                    is = httpEntity.getContent();
                }else if(method == "GET"){
                    // request method is GET
                    DefaultHttpClient httpClient = new DefaultHttpClient();
                    String paramString = URLEncodedUtils.format(params, "utf-8");
                    url += "?" + paramString;
                    HttpGet httpGet = new HttpGet(url);
                    HttpResponse httpResponse = httpClient.execute(httpGet);
                    HttpEntity httpEntity = httpResponse.getEntity();
                    is = httpEntity.getContent();
                }           
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                BufferedReader reader = new BufferedReader(new InputStreamReader(
                        is, "iso-8859-1"), 8);
                StringBuilder sb = new StringBuilder();
                String line = null;
                while ((line = reader.readLine()) != null) {
                    sb.append(line + "\n");
                }
                is.close();
                json = sb.toString();
            } catch (Exception e) {
                Log.e("Buffer Error", "Error converting result " + e.toString());
            }
            // try parse the string to a JSON object
            try {
                jObj = new JSONObject(json);
            } catch (JSONException e) {
                Log.e("JSON Parser", "Error parsing data " + e.toString());
            }
            // return JSON String
            return jObj;
        }
}

Answer 1

DefaultHttpClient 在 api 级别 22 中被弃用，并在 api 级别 23 中被删除。

该文档甚至已从 Android 文档中删除，这里是文档之前所在位置的链接，您可以看到它重定向到的位置: http://developer.android.com/reference/org/apache/http/impl/client/DefaultHttpClient.html

引用以防重定向更改:

Android 6.0 release removes support for the Apache HTTP client. If your app is using this client and targets Android 2.3 (API level 9) or higher, use the HttpURLConnection class instead. This API is more efficient because it reduces network use through transparent compression and response caching, and minimizes power consumption.

我创建了您正在使用的 JSONParser 类的更新版本，它是:

import android.util.Log;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;

public class JSONParser {

    String charset = "UTF-8";
    HttpURLConnection conn;
    DataOutputStream wr;
    StringBuilder result;
    URL urlObj;
    JSONObject jObj = null;
    StringBuilder sbParams;
    String paramsString;

    public JSONObject makeHttpRequest(String url, String method,
                                      HashMap<String, String> params) {

        sbParams = new StringBuilder();
        int i = 0;
        for (String key : params.keySet()) {
            try {
                if (i != 0){
                    sbParams.append("&");
                }
                sbParams.append(key).append("=")
                        .append(URLEncoder.encode(params.get(key), charset));

            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            i++;
        }

        if (method.equals("POST")) {
            // request method is POST
            try {
                urlObj = new URL(url);

                conn = (HttpURLConnection) urlObj.openConnection();

                conn.setDoOutput(true);

                conn.setRequestMethod("POST");

                conn.setRequestProperty("Accept-Charset", charset);

                conn.setReadTimeout(10000);
                conn.setConnectTimeout(15000);

                conn.connect();

                paramsString = sbParams.toString();

                wr = new DataOutputStream(conn.getOutputStream());
                wr.writeBytes(paramsString);
                wr.flush();
                wr.close();

            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        else if(method.equals("GET")){
            // request method is GET

            if (sbParams.length() != 0) {
                url += "?" + sbParams.toString();
            }

            try {
                urlObj = new URL(url);

                conn = (HttpURLConnection) urlObj.openConnection();

                conn.setDoOutput(false);

                conn.setRequestMethod("GET");

                conn.setRequestProperty("Accept-Charset", charset);

                conn.setConnectTimeout(15000);

                conn.connect();

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

        }

        try {
            //Receive the response from the server
            InputStream in = new BufferedInputStream(conn.getInputStream());
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            result = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                result.append(line);
            }

            Log.d("JSON Parser", "result: " + result.toString());

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

        conn.disconnect();

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(result.toString());
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON Object
        return jObj;
    }
}

帖子的 AsyncTask 示例:

class PostAsync extends AsyncTask<String, String, JSONObject> {
    JSONParser jsonParser = new JSONParser();

    private ProgressDialog pDialog;

    private static final String LOGIN_URL = "http://www.example.com/testPost.php";

    private static final String TAG_SUCCESS = "success";
    private static final String TAG_MESSAGE = "message";


    @Override
    protected void onPreExecute() {
        pDialog = new ProgressDialog(MainActivity.this);
        pDialog.setMessage("Attempting login...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }

    @Override
    protected JSONObject doInBackground(String... args) {

        try {

            HashMap<String, String> params = new HashMap<>();
            params.put("name", args[0]);
            params.put("password", args[1]);

            Log.d("request", "starting");

            JSONObject json = jsonParser.makeHttpRequest(
                    LOGIN_URL, "POST", params);

            if (json != null) {
                Log.d("JSON result", json.toString());

                return json;
            }

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

        return null;
    }

    protected void onPostExecute(JSONObject json) {

        int success = 0;
        String message = "";

        if (pDialog != null && pDialog.isShowing()) {
            pDialog.dismiss();
        }

        if (json != null) {
            Toast.makeText(MainActivity.this, json.toString(),
                    Toast.LENGTH_LONG).show();

            try {
                success = json.getInt(TAG_SUCCESS);
                message = json.getString(TAG_MESSAGE);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

        if (success == 1) {
            Log.d("Success!", message);
        }else{
            Log.d("Failure", message);
        }
    }

}

Get 的 AsyncTask 示例:

class GetAsync extends AsyncTask<String, String, JSONObject> {

    JSONParser jsonParser = new JSONParser();

    private ProgressDialog pDialog;

    private static final String LOGIN_URL = "http://www.example.com/testGet.php";

    private static final String TAG_SUCCESS = "success";
    private static final String TAG_MESSAGE = "message";

    @Override
    protected void onPreExecute() {
        pDialog = new ProgressDialog(MainActivity.this);
        pDialog.setMessage("Attempting login...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }

    @Override
    protected JSONObject doInBackground(String... args) {

        try {

            HashMap<String, String> params = new HashMap<>();
            params.put("name", args[0]);
            params.put("password", args[1]);

            Log.d("request", "starting");

            JSONObject json = jsonParser.makeHttpRequest(
                    LOGIN_URL, "GET", params);

            if (json != null) {
                Log.d("JSON result", json.toString());

                return json;
            }

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

        return null;
    }

    protected void onPostExecute(JSONObject json) {

        int success = 0;
        String message = "";

        if (pDialog != null && pDialog.isShowing()) {
            pDialog.dismiss();
        }

        if (json != null) {
            Toast.makeText(MainActivity.this, json.toString(),
                    Toast.LENGTH_LONG).show();

            try {
                success = json.getInt(TAG_SUCCESS);
                message = json.getString(TAG_MESSAGE);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

        if (success == 1) {
            Log.d("Success!", message);
        }else{
            Log.d("Failure", message);
        }
    }

}

有关详细信息，这是我关于此代码的博客文章:http://danielnugent.blogspot.com/2015/06/updated-jsonparser-with.html