一、项目背景
在Android开发中有一项非常广泛的应用:Android项目获取另一个web项目的资源或者返回的数据。
本文获取web项目返回的JSON数据。Android应用解析JSON比XML性能要好,但有许多项目仍然采用的是XML。
二、实例代码
Web项目
[java]
/**
* 新闻业务类
*
* @author 徐越
*
*/
public class VideoNewsServiceImpl implements VideoNewsService
{
public List<VideoNews> readNews()
{
List<VideoNews> lst = new ArrayList<VideoNews>();
lst.add(new VideoNews(1, "喜洋洋", 20));
lst.add(new VideoNews(2, "变形金刚", 10));
lst.add(new VideoNews(3, "功夫熊猫", 20));
return lst;
}
}
/**
* 新闻Servlet
*
* @author 徐越
*
*/
public class ListServlet extends HttpServlet
{
private static final long serialVersionUID = 1L;
private VideoNewsService vs = new VideoNewsServiceImpl();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
List<VideoNews> news = vs.readNews();
JSONArray jsonarr = JSONArray.fromObject(news);
response.setCharacterEncoding("UTF-8");
response.setContentType("text/plain;charset=UTF-8");
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.getWriter().print(jsonarr);
}
}
/**
* 新闻业务类
*
* @author 徐越
*
*/
public class VideoNewsServiceImpl implements VideoNewsService
{
public List<VideoNews> readNews()
{
List<VideoNews> lst = new ArrayList<VideoNews>();
lst.add(new VideoNews(1, "喜洋洋", 20));
lst.add(new VideoNews(2, "变形金刚", 10));
lst.add(new VideoNews(3, "功夫熊猫", 20));
return lst;
}
}
/**
* 新闻Servlet
*
* @author 徐越
*
*/
public class ListServlet extends HttpServlet
{
private static final long serialVersionUID = 1L;
private VideoNewsService vs = new VideoNewsServiceImpl();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
List<VideoNews> news = vs.readNews();
JSONArray jsonarr = JSONArray.fromObject(news);
response.setCharacterEncoding("UTF-8");
response.setContentType("text/plain;charset=UTF-8");
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.getWriter().print(jsonarr);
}
}
Android项目
[java] view plaincopyprint?
public class VideoNewsServiceImpl implements VideoNewsService
{
/**
* 获取最新视频资讯,从JSON文件中,解析效率高
*
* @return
* @throws Exception
*/
public List<VideoNews> getNewsFromJson() throws Exception
{
List<VideoNews> lst = new ArrayList<VideoNews>();
String path = "http://xxx.xxx.xxx.xxx:8080/web/ListServlet";
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(5000);
conn.setRequestMethod("GET");
if (200 == conn.getResponseCode())
{
InputStream instream = conn.getInputStream();
lst = parseJSON(instream);
}
return lst;
}
/**
* 解析JSON
*/
private List<VideoNews> parseJSON(InputStream instream) throws Exception
{
List<VideoNews> lst = new ArrayList<VideoNews>();
byte[] data = IOUtils.read(instream);
String jsonStr = new String(data);
JSONArray array = new JSONArray(jsonStr);
for (int i = 0; i < array.length(); i++)
{
JSONObject jsonObj = (JSONObject) array.getJSONObject(i);
VideoNews v = new VideoNews(jsonObj.getInt("id"),
jsonObj.getString("title"), jsonObj.getInt("timeLength"));
lst.add(v);
补充:移动开发 , Android ,