android与服务器端数据交互 android 服务器

下面就几个小点做概要说明，另外，北风网的《零基础android课程》中对android平台中客户端与web服务器(课程中用到的是Tomcat)建立连接、请求网络资源的方式、大数据传输原理、断点续传等较为详细的讲解，建议你不妨购买学习。

1.android客户端和服务通信主要用http编程和socket编程

2.对于GET请求和POST请求，android平台有自己封装的AndroidHttpClient对象

3.Client和Web Server传递数据的格式一般用XML和JSON两种

4.由于和Web Server通信的过程中涉及到图片、访问Web端数据库等耗时的操作，android Client不会把这些操作放到主线程中去执行，以避免主线程阻塞、ANR等错误，当然在后台Service的中开启线程可以，但是android有自己的处理方式，handler机制、AsyncTask机制等。

5.因为你在问题中提到了“需要连接web服务器”，所以以下写两段android中的代码仅供参考：

/**
      * @author shengyp
      * @param urlString url地址
      * @param xml 传递xml数据
      * @param hashMap 设置头参数
      * @return 服务器返回结果
      * @throws Exception
      */
     public static String sendXml(String urlString, String xml, HashMap<String, String> hashMap)
             throws Exception {
         byte[] data = xml.getBytes();
         URL url = new URL(urlString);
         HttpURLConnection conn = (HttpURLConnection) url.openConnection();
         conn.setRequestMethod("POST");
         conn.setConnectTimeout(10000);
         hashMap.put("Content-Type", "text/xml; charset=UTF-8");
         hashMap.put("Content-Length", String.valueOf(data.length));
         conn.setDoOutput(true);
         conn.setDoInput(true);
         conn.setUseCaches(false);
         for (String key : hashMap.keySet()) {
             conn.setRequestProperty(key, hashMap.get(key));
             // System.out.println("key= " + key + "  and  value= " +
             // hashMap.get(key));
         }
         conn.connect();
         OutputStream outStream = conn.getOutputStream();
         outStream.write(data);
         outStream.flush();
         outStream.close();
         String returnXml = "";
         if (conn.getResponseCode() == 200)
         {
             InputStream inputStream = conn.getInputStream();
             BufferedReader dataInputStream = new BufferedReader(new InputStreamReader(inputStream, "utf-8"));
             String line = "";
             while ((line = dataInputStream.readLine()) != null) {
                 returnXml += line;
             }
             // Log.d(TAG, returnXml);
             return returnXml;
         }
         return null;
     }
     /**
      * 通过Httppost传递参数
      * 
      * @param urlString 地址
      * @param code 编码
      * @param heads 请求
      * @param xml 要传的参数
      * @return 
      * @throws Exception
      */
     public static String httpPost(String urlString, String code, HashMap<String, String> heads,
             String xml) throws Exception
     {
         DefaultHttpClient httpClient = new DefaultHttpClient();
         HttpPost post = new HttpPost(urlString);
         if (heads != null)
         {
             for (HashMap.Entry<String, String> entry : heads.entrySet())
             {
                 post.setHeader(entry.getKey(), entry.getValue());
             }
         }
         StringEntity entity = new StringEntity(xml, code);
         post.setEntity(entity);
         HttpResponse response = httpClient.execute(post);
         HttpEntity httpEntity = response.getEntity();
         InputStream is = httpEntity.getContent();
         StringBuffer sb = new StringBuffer();
         BufferedReader br = new BufferedReader(new InputStreamReader(is));
         String line = "";
         while ((line = br.readLine()) != null)
         {
             sb.append(line);
         }
         return sb.toString();
     }