Android 网络请求

##HttpClient (Apache)
6.0中已经移除了这个方法，Google建议使用HttpUrlConnection 见Android 6.0 Changes

###GET 方法

• 新建一个HttpGet对象

  HttpGet httpGet = new HttpGet("https://baidu.com");

• 获取HtttpClient实例

  HttpClient httpClient = new DefaultHttpClient();

• 获取HttpResponse实例 并传入HttpGet对象

  HttpResponse response = httpClient.execute(httpGet);

• 判断是否请求成功

  if(response.getStatusLine().getStatusCode()==200)
  {//do something
  HttpEntity httpEntity = response.getEntity();
  String result = EntityUtils.toString(httpEntity);
  String result = EntityUtils.toString(response.getEntity(),"UTF-8");//带中文的话
  }

POST 方法

• 新建一个HttpGet对象

  HttpGet httpPost = new HttpPost("https://baidu.com");

• 获取HtttpClient实例

  HttpClient httpClient = new DefaultHttpClient();

• 设置POST参数(1)

  List<NameValuePair> params = new ArrayList<NameValuePair>();
  params.add(new BasicNameValuePair("username", "username"));
  params.add(new BasicNameValuePair("password", "password"));
  //添加内容到请求中
  UrlEncodedFormEntity entity = new UrlEncodedFromEntity(params,"UTF-8");
  httpPost.setEntity(entity);

• 设置POST参数(2)

  NameValuePair namePair = new BasicNameValuePair("username","username");
  NameValuePair pswPair = new BasicNameValuePair("password","password");
  List<NameValuePair> pairList = new ArrayList<NameValuePair>();
  pariList.add(namePair);
  //添加内容到请求中
  HttpEntity httpEntity = new UrlEncodedFormEntity(pairlist);
  httpPost.setEntity(httpEntity);

• 获取HttpResponse实例 并传入HttpGet对象

  HttpResponse response = httpClient.execute(httpPost);

• 判断是否请求成功

  if(response.getStatusLine().getStatusCode()==200)
  {//do something
  HttpEntity httpEntity = response.getEntity();
  String result = EntityUtils.toString(httpEntity);
  //String result = EntityUtils.toString(response.getEntity(),”UTF-8”);//带中文的话
  }

  ##HttpUrlConnection

GET 方法

• 先new一个Url 对象，并传入网址

  Url url = new Url("https://baidu.com");

• 打开一个HttpUrlConnection连接

  HttpUrlConnection httpUrlConnection = (HttpUrlConnection) url.openConnection();

• 设置get或者post方法

  httpUrlConnection.setRequestMethod(“GET”);

• 定制一些信息 比如超时时间，title等
• 调用getInputStream 获取服务器返回的输入流

  InputStream in = httpUrlConnection.getInputStream();
  //对获取到的输入流进行读取
  BufferedReader reader = new BufferedReader(new InputStreamReader(in));
  StringBuilder response = new StringBuilder();
  String line;
  while ((line = reader.readLine()) != null) {
      response.append(line);
  }

• 关闭连接

  httpUrlConnection.disconnect();

  POST 方法

• 前面都一样

  httpUrlConnection.setRequestMethod("POST");
  DataOutputStream dataOutputStream = new DataOutputStream(httpUrlConnection.getOutputStream);
  dataOutputStream.writeBytes("username=XXX&password=YYY");