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用android发出HTTP请求

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

如果可能的话我甚至想在后台(在BroadcastReceiver中)这样做

11 回答

  • 64

    更新

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

    原始答案

    首先,请求访问网络的权限,在清单中添加以下内容:

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

    那么最简单的方法是使用与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());
        }
    

    如果你想让它在单独的线程上运行,我建议扩展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");
    
  • 0

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

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

    我们在官方博客上谈到了权衡:http://android-developers.blogspot.com/2011/09/androids-http-clients.html

  • 3

    注意:现在不推荐使用与Android捆绑在一起的Apache HTTP Client,而使用HttpURLConnection . 有关详细信息,请参阅Android开发人员Blog .

    <uses-permission android:name="android.permission.INTERNET" /> 添加到清单中 .

    然后,您将检索如下所示的网页:

    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();
    }
    

    我还建议在一个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documentation .

  • 3

    最简单的方法是使用名为Volley的Android库

    Volley提供以下好处:自动调度网络请求 . 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 . 强大的排序功能,可以使用从网络异步获取的数据轻松正确填充UI . 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,您不必考虑自己“在后台运行”或“使用缓存”,因为所有这些都已由Volley完成 .

  • 5
    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

  • 1

    有一个线程:

    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);
        }
    }
    
  • 2

    看看这个可以通过gradle获得的真棒新库:)

    build.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

  • 1

    我使用Gson lib为web服务创建了这个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;
    }
    
  • 10

    这是android中HTTP Get / POST请求的新代码 . HTTPClient 已被删除,可能无法使用,就像我的情况一样 .

    首先在build.gradle中添加两个依赖项:

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

    然后在 ASyncTask 中以 doBackground 方法编写此代码 .

    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
     }
    
  • 40

    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,并且我们也可以为每个请求创建自定义标头:

    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方法轻松地异步进行

  • 459

    由于没有一个答案描述了使用OkHttp执行请求的方法,这对于Android和Java来说是非常流行的http客户端,我将提供一个简单的例子:

    //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从一些低级细节中抽象出我们,提供了更友好和安全的方式来与它们进行交互 . 语法也简化了,允许编写漂亮的代码 .

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