一、HttpClient

Android SDK中包含了HttpClient，在Android6.0版本直接刪除了HttpClient類庫，如果仍想使用則解決方法是：

• 如果使用的是eclipse則在libs中加入org.apache.http.legacy.jar
  這個jar包在：**sdk\platforms\android-23\optional目錄中（需要下載android
  6.0的SDK）
• 如果使用的是android studio則 在相應的module下的build.gradle中加入：

useLibrary 'org.apache.http.legacy'

}

HttpClient的GET請求

首先我們來用DefaultHttpClient類來例項化一個HttpClient，並配置好預設的請求引數：

//建立HttpClient

private HttpClient createHttpClient() {

HttpParams mDefaultHttpParams = new BasicHttpParams();

//設定連線超時

HttpConnectionParams.setConnectionTimeout(mDefaultHttpParams, 15000);

//設定請求超時

HttpConnectionParams.setSoTimeout(mDefaultHttpParams,

HttpConnectionParams.setTcpNoDelay(mDefaultHttpParams, true);

HttpProtocolParams.setVersion(mDefaultHttpParams, HttpVersion.HTTP_1_1);

HttpProtocolParams.setContentCharset(mDefaultHttpParams, HTTP.UTF_8);

//持續握手

HttpProtocolParams.setUseExpectContinue(mDefaultHttpParams, true);

HttpClient mHttpClient =

return mHttpClient;

}

接下來建立HttpGet和HttpClient，請求網路並得到HttpResponse，並對HttpResponse進行處理：

private void useHttpClientGet(String url) {

HttpGet mHttpGet = new HttpGet(url);

mHttpGet.addHeader("Connection", "Keep-Alive");

try {

HttpClient mHttpClient = createHttpClient();

HttpResponse mHttpResponse = mHttpClient.execute(mHttpGet);

HttpEntity mHttpEntity = mHttpResponse.getEntity();

int code = mHttpResponse.getStatusLine().getStatusCode();

if (null != mHttpEntity) {

InputStream mInputStream = mHttpEntity.getContent();

String respose = converStreamToString(mInputStream);

Log.i("wangshu", "請求狀態碼:" + code + "\n請求結果:\n" + respose);

mInputStream.close();

}

} catch (IOException e) {

e.printStackTrace();

}

}

converStreamToString方法將請求結果轉換成String型別：

private String converStreamToString(InputStream is) throws IOException {
      BufferedReader reader = new BufferedReader(new InputStreamReader(is));
      StringBuffer sb = new StringBuffer();
      String line = null;
      while ((line = reader.readLine()) != null) {
         sb.append(line + "\n");
      }
      String respose = sb.toString();
      return respose;
}

最後我們開啟執行緒訪問百度：

new Thread(new Runnable() {
@Override
public void run() {
      useHttpClientGet("http://www.baidu.com");
      }

}).start();

請求的返回結果，請求狀態碼為200，結果就是個html頁，這裡只截取了部分html程式碼：

GET請求的引數暴露在URL中，這有些不大妥當，而且URL的長度也有限制：長度在2048字元之內，在HTTP 1.1後URL長度才沒有限制。一般情況下POST可以替代GET，接下來我們來看看HttpClient的POST請求。

HttpClient的POST請求

post請求和get類似就是需要配置要傳遞的引數：

private void useHttpClientPost(String url) {
   HttpPost mHttpPost = new HttpPost(url);
   mHttpPost.addHeader("Connection", "Keep-Alive");
   try {
      HttpClient mHttpClient = createHttpClient();
      List<NameValuePair> postParams = new ArrayList<>();
      //要傳遞的引數
postParams.add(new BasicNameValuePair("username", "moon"));
      postParams.add(new BasicNameValuePair("password", "123"));
      mHttpPost.setEntity(new UrlEncodedFormEntity(postParams));
      HttpResponse mHttpResponse = mHttpClient.execute(mHttpPost);
      HttpEntity mHttpEntity = mHttpResponse.getEntity();
      int code = mHttpResponse.getStatusLine().getStatusCode();
      if (null != mHttpEntity) {
         InputStream mInputStream = mHttpEntity.getContent();
         String respose = converStreamToString(mInputStream);
         Log.i("wangshu", "請求狀態碼:" + code + "\n請求結果:\n" + respose);
         mInputStream.close();
      }
   } catch (IOException e) {
      e.printStackTrace();
   }
}

public static void postParams(OutputStream output,List<NameValuePair>paramsList) throws IOException{
   StringBuilder mStringBuilder=new StringBuilder();
   for (NameValuePair pair:paramsList){
      if(!TextUtils.isEmpty(mStringBuilder)){
         mStringBuilder.append("&");
      }
      mStringBuilder.append(URLEncoder.encode(pair.getName(),"UTF-8"));
      mStringBuilder.append("=");
      mStringBuilder.append(URLEncoder.encode(pair.getValue(),"UTF-8"));
   }
   BufferedWriter writer=new BufferedWriter(new OutputStreamWriter(output,"UTF-8"));
   writer.write(mStringBuilder.toString());
   writer.flush();
   writer.close();
}

private void useHttpUrlConnectionPost(String url) {
   InputStream mInputStream = null;
   HttpURLConnection mHttpURLConnection = UrlConnManager.getHttpURLConnection(url);
   try {
      List<NameValuePair> postParams = new ArrayList<>();
      //要傳遞的引數
postParams.add(new BasicNameValuePair("username", "moon"));
      postParams.add(new BasicNameValuePair("password", "123"));
      UrlConnManager.postParams(mHttpURLConnection.getOutputStream(), postParams);
      mHttpURLConnection.connect();
      mInputStream = mHttpURLConnection.getInputStream();
      int code = mHttpURLConnection.getResponseCode();
      String respose = converStreamToString(mInputStream);
      Log.i("wangshu", "請求狀態碼:" + code + "\n請求結果:\n" + respose);
      mInputStream.close();
   } catch (IOException e) {
      e.printStackTrace();
   }
}

最後開啟執行緒請求網路：

private void useHttpUrlConnectionGetThread() {
new Thread(new Runnable() {
@Override
public void run() {
      useHttpUrlConnectionPost("http://www.baidu.com");
      }
      }).start();
}