Http:

1从网络获取数据

a从网络获取图片,以byte[]字节数组保存，并构建一个Bitmap

b.从网络获取为xml/Json，要解析，并封装成对象。

public byte[] getNetImage(String path) throws IOException{　　URL url = new URL(path);　　HttpURLConnection connection =(HttpURLConnection) url.openConnection();//基于HTTP协议连接对象　　connection.setConnectTimeout(5000);　　connection.setRequestMethod("GET");　　if(connection.getResponseCode() == HttpURLConnection.HTTP_OK){　　    InputStream in =connection.getInputStream();　　    return Utils.readStream(in);　　}　　return null;} //将流读取到字节数组public static byte[] readStream(InputStream in) throws IOException {　　ByteArrayOutputStream baos = new ByteArrayOutputStream();　　byte[] buffer = new byte[1024];　　int len = 0;　　while ((len = in.read(buffer)) != -1) {　　    baos.write(buffer, 0, len);　　}　　return baos.toByteArray();}

2 以GET/POST方式上传到服务器

a.通过HTTP发送参数到服务器

GET不适合传输大数据

　　组拼url路径后的参数

POST:Content-Type Content-Length

　　组拼将要发送的实体数据

 

HttpClient开源项目

　　使用UrlEncodedFormEntity类构造实体数据

　　内部做了很多封装，性能不如手写的GET/POST

　　操作HTTPS,Cookie编码简单些 

// 发送POST请求public static boolean sendPostRequest(String path, Map
      
        params, String encoding)throws IOException {　　StringBuilder builder = new StringBuilder();　　for (Map.Entry
       
         entry : params.entrySet()) {　　　　builder.append("?").append(entry.getKey()).append("=").append(entry.getValue()).append("&");　　}　　builder.deleteCharAt(builder.length() - 1);　　URL url = new URL(path);　　HttpURLConnection connection = (HttpURLConnection) url.openConnection();　　connection.setConnectTimeout(5000);　　connection.setRequestMethod("POST");　　connection.addRequestProperty("Content-Type", "");　　connection.addRequestProperty("Content-Length", String.valueOf(builder.length()));　　connection.setDoOutput(true);　　OutputStream os = connection.getOutputStream();　　os.write(builder.toString().getBytes());// 只有取得服务器响应消息，才真正发送除数据，现在仅放到内存　　if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {　　    return true;　　}　　return false;} // HttpClientpublic static boolean sendHttpClientRequest(String path, Map
        
          params,String encoding) throws IOException {　　List
         
           valuePairs = new ArrayList
          
           ();　　for (Map.Entry
           
             entry : params.entrySet()) {　　 valuePairs.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));　　}　　UrlEncodedFormEntity entity = new UrlEncodedFormEntity(valuePairs, encoding);// 构造实体数据　　HttpPost post = new HttpPost(path);// 构造POST请求　　post.setEntity(entity);　　DefaultHttpClient client = new DefaultHttpClient();// 构造一个浏览器　　HttpResponse response = client.execute(post);　　if (response.getStatusLine().getStatusCode() == 200) {　　 return true;　　}　　return false;}
           
          
         
        
       
      

b.通过Socket上传文件到服务器

先判断文件是否存在

HttpClient内部使用缓存，当上传文件超过1M，产生内存溢出Socket

实体数据长度= 文本类型长度+文件类型长度