373

我到处搜索,但找不到答案,有没有办法发出简单的 HTTP 请求?我想在我的一个网站上请求一个 PHP 页面/脚本,但我不想显示该网页。

如果可能的话,我什至想在后台进行(在广播接收器中)

4

12 回答 12

490

更新

这是一个非常古老的答案。我绝对不会再推荐 Apache 的客户端了。而是使用:

原始答案

首先,请求访问网络的权限,在您的清单中添加以下内容:

<uses-permission android:name="android.permission.INTERNET" />

那么最简单的方法就是使用 Android 捆绑的 Apache http 客户端:

    HttpClient httpclient = new DefaultHttpClient();
    HttpResponse response = httpclient.execute(new HttpGet(URL));
    StatusLine statusLine = response.getStatusLine();
    if(statusLine.getStatusCode() == HttpStatus.SC_OK){
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        response.getEntity().writeTo(out);
        String responseString = out.toString();
        out.close();
        //..more logic
    } else{
        //Closes the connection.
        response.getEntity().getContent().close();
        throw new IOException(statusLine.getReasonPhrase());
    }

如果您希望它在单独的线程上运行,我建议您扩展 AsyncTask:

class RequestTask extends AsyncTask<String, String, String>{

    @Override
    protected String doInBackground(String... uri) {
        HttpClient httpclient = new DefaultHttpClient();
        HttpResponse response;
        String responseString = null;
        try {
            response = httpclient.execute(new HttpGet(uri[0]));
            StatusLine statusLine = response.getStatusLine();
            if(statusLine.getStatusCode() == HttpStatus.SC_OK){
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                response.getEntity().writeTo(out);
                responseString = out.toString();
                out.close();
            } else{
                //Closes the connection.
                response.getEntity().getContent().close();
                throw new IOException(statusLine.getReasonPhrase());
            }
        } catch (ClientProtocolException e) {
            //TODO Handle problems..
        } catch (IOException e) {
            //TODO Handle problems..
        }
        return responseString;
    }
    
    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        //Do anything with response..
    }
}

然后,您可以通过以下方式提出请求:

   new RequestTask().execute("http://stackoverflow.com");
于 2010-08-17T19:11:11.840 回答
68

除非您有明确的理由选择 Apache HttpClient,否则您应该更喜欢 java.net.URLConnection。你可以在网上找到很多关于如何使用它的例子。

自您发布原始帖子以来,我们还改进了 Android 文档:http: //developer.android.com/reference/java/net/HttpURLConnection.html

我们已经在官方博客上讨论过权衡取舍:http ://android-developers.blogspot.com/2011/09/androids-http-clients.html

于 2010-08-18T05:55:59.937 回答
47

注意:与 Android 捆绑的 Apache HTTP 客户端现在已弃用,取而代之的是HttpURLConnection。有关详细信息,请参阅 Android 开发者博客。

添加<uses-permission android:name="android.permission.INTERNET" />到您的清单中。

然后你会像这样检索一个网页:

URL url = new URL("http://www.android.com/");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
     InputStream in = new BufferedInputStream(urlConnection.getInputStream());
     readStream(in);
}
finally {
     urlConnection.disconnect();
}

我还建议在单独的线程上运行它:

class RequestTask extends AsyncTask<String, String, String>{

@Override
protected String doInBackground(String... uri) {
    String responseString = null;
    try {
        URL url = new URL(myurl);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        if(conn.getResponseCode() == HttpsURLConnection.HTTP_OK){
            // Do normal input or output stream reading
        }
        else {
            response = "FAILED"; // See documentation for more info on response handling
        }
    } catch (ClientProtocolException e) {
        //TODO Handle problems..
    } catch (IOException e) {
        //TODO Handle problems..
    }
    return responseString;
}

@Override
protected void onPostExecute(String result) {
    super.onPostExecute(result);
    //Do anything with response..
}
}

有关响应处理和 POST 请求的更多信息,请参阅文档。

于 2015-06-30T20:54:20.940 回答
14

最简单的方法是使用名为Volley的 Android 库

Volley 提供以下好处:

网络请求的自动调度。多个并发网络连接。具有标准 HTTP 缓存一致性的透明磁盘和内存响应缓存。支持请求优先级。取消请求 API。您可以取消单个请求,也可以设置要取消的请求块或范围。易于定制,例如重试和退避。强大的排序使得使用从网络异步获取的数据正确填充 UI 变得容易。调试和跟踪工具。

您可以像这样简单地发送 http/https 请求:

        // Instantiate the RequestQueue.
        RequestQueue queue = Volley.newRequestQueue(this);
        String url ="http://www.yourapi.com";
        JsonObjectRequest request = new JsonObjectRequest(url, null,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    if (null != response) {
                         try {
                             //handle your response
                         } catch (JSONException e) {
                             e.printStackTrace();
                         }
                    }
                }
            }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError error) {

            }
        });
        queue.add(request);

在这种情况下,您无需自己考虑“在后台运行”或“使用缓存”,因为所有这些都已由 Volley 完成。

于 2017-05-27T05:08:15.493 回答
8

按照上面的建议使用 Volley。将以下内容添加到 build.gradle (Module: app)

implementation 'com.android.volley:volley:1.1.1'

在 AndroidManifest.xml 中添加以下内容:

<uses-permission android:name="android.permission.INTERNET" />

并将以下内容添加到您的活动代码中:

public void httpCall(String url) {

    RequestQueue queue = Volley.newRequestQueue(this);

    StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    // enjoy your response
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    // enjoy your error status
                }
    });

    queue.add(stringRequest);
}

它取代了http客户端,而且非常简单。

于 2019-09-28T09:22:29.580 回答
6
private String getToServer(String service) throws IOException {
    HttpGet httpget = new HttpGet(service);
    ResponseHandler<String> responseHandler = new BasicResponseHandler();
    return new DefaultHttpClient().execute(httpget, responseHandler);

}

问候

于 2014-07-30T18:07:39.610 回答
5

用一个线程:

private class LoadingThread extends Thread {
    Handler handler;

    LoadingThread(Handler h) {
        handler = h;
    }
    @Override
    public void run() {
        Message m = handler.obtainMessage();
        try {
            BufferedReader in = 
                new BufferedReader(new InputStreamReader(url.openStream()));
            String page = "";
            String inLine;

            while ((inLine = in.readLine()) != null) {
                page += inLine;
            }

            in.close();
            Bundle b = new Bundle();
            b.putString("result", page);
            m.setData(b);
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        handler.sendMessage(m);
    }
}
于 2010-08-17T19:03:32.707 回答
5

由于没有一个答案描述了使用 OkHttp 执行请求的方法,OkHttp是当今 Android 和 Java 中非常流行的 http 客户端,我将提供一个简单的示例:

//get an instance of the client
OkHttpClient client = new OkHttpClient();

//add parameters
HttpUrl.Builder urlBuilder = HttpUrl.parse("https://www.example.com").newBuilder();
urlBuilder.addQueryParameter("query", "stack-overflow");


String url = urlBuilder.build().toString();

//build the request
Request request = new Request.Builder().url(url).build();

//execute
Response response = client.newCall(request).execute();

这个库的明显优势在于它将我们从一些低级细节中抽象出来,提供了更友好和安全的方式来与它们交互。语法也被简化并允许编写漂亮的代码。

于 2018-06-11T18:59:43.527 回答
4

我使用 Gson 库为 Web 服务请求 URL:

客户:

public EstabelecimentoList getListaEstabelecimentoPorPromocao(){

        EstabelecimentoList estabelecimentoList  = new EstabelecimentoList();
        try{
            URL url = new URL("http://" +  Conexao.getSERVIDOR()+ "/cardapio.online/rest/recursos/busca_estabelecimento_promocao_android");
            HttpURLConnection con = (HttpURLConnection) url.openConnection();

            if (con.getResponseCode() != 200) {
                    throw new RuntimeException("HTTP error code : "+ con.getResponseCode());
            }

            BufferedReader br = new BufferedReader(new InputStreamReader((con.getInputStream())));
            estabelecimentoList = new Gson().fromJson(br, EstabelecimentoList.class);
            con.disconnect();

        } catch (IOException e) {
            e.printStackTrace();
        }
        return estabelecimentoList;
}
于 2014-06-05T13:51:02.193 回答
4

看看这个可以通过 gradle 获得的很棒的新库 :)

构建.gradle:compile 'com.apptakk.http_request:http-request:0.1.2'

用法:

new HttpRequestTask(
    new HttpRequest("http://httpbin.org/post", HttpRequest.POST, "{ \"some\": \"data\" }"),
    new HttpRequest.Handler() {
      @Override
      public void response(HttpResponse response) {
        if (response.code == 200) {
          Log.d(this.getClass().toString(), "Request successful!");
        } else {
          Log.e(this.getClass().toString(), "Request unsuccessful: " + response);
        }
      }
    }).execute();

https://github.com/erf/http-request

于 2016-05-04T00:00:09.657 回答
2

这是 android 中 HTTP Get/POST 请求的新代码。HTTPClient已被贬低,可能无法像我的情况那样使用。

首先在build.gradle中添加两个依赖:

compile 'org.apache.httpcomponents:httpcore:4.4.1'
compile 'org.apache.httpcomponents:httpclient:4.5'

然后将这段代码写在ASyncTaskindoBackground方法中。

 URL url = new URL("http://localhost:8080/web/get?key=value");
 HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
 urlConnection.setRequestMethod("GET");
 int statusCode = urlConnection.getResponseCode();
 if (statusCode ==  200) {
      InputStream it = new BufferedInputStream(urlConnection.getInputStream());
      InputStreamReader read = new InputStreamReader(it);
      BufferedReader buff = new BufferedReader(read);
      StringBuilder dta = new StringBuilder();
      String chunks ;
      while((chunks = buff.readLine()) != null)
      {
         dta.append(chunks);
      }
 }
 else
 {
     //Handle else
 }
于 2016-03-29T19:34:24.220 回答
1

对我来说,最简单的方法是使用名为Retrofit2的库

我们只需要创建一个包含我们的请求方法、参数的接口,我们还可以为每个请求制作自定义标头:

    public interface MyService {

      @GET("users/{user}/repos")
      Call<List<Repo>> listRepos(@Path("user") String user);

      @GET("user")
      Call<UserDetails> getUserDetails(@Header("Authorization") String   credentials);

      @POST("users/new")
      Call<User> createUser(@Body User user);

      @FormUrlEncoded
      @POST("user/edit")
      Call<User> updateUser(@Field("first_name") String first, 
                            @Field("last_name") String last);

      @Multipart
      @PUT("user/photo")
      Call<User> updateUser(@Part("photo") RequestBody photo, 
                            @Part("description") RequestBody description);

      @Headers({
        "Accept: application/vnd.github.v3.full+json",
        "User-Agent: Retrofit-Sample-App"
      })
      @GET("users/{username}")
      Call<User> getUser(@Path("username") String username);    

    }

最好的是,我们可以使用 enqueue 方法轻松地异步完成

于 2017-04-02T20:49:26.783 回答