Android開發17——獲取網絡資源之XML數據

本文出自 “IT徐胖子的專欄” 博客，請務必保留此出處http://woshixy.blog.51cto.com/5637578/1088051

一、項目背景

在Android開發中有一項非常廣泛的應用：Android項目獲取另一個web項目的資源或者返回的數據。本文獲取web項目返回的XML數據。

二、實例代碼

Web項目

/**
 * 新聞業務類
 *
 * @author 徐越
 *
 */
publicclass 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, "變形金剛", 10));
        lst.add(new VideoNews(3, "功夫熊貓", 20));
return lst;
    }
}

/**
 * 新聞Servlet
 *
 * @author 徐越
 *
 */
publicclass ListServlet extends HttpServlet
{
privatestaticfinallong serialVersionUID = 1L;
private VideoNewsService vs = new VideoNewsServiceImpl();

protectedvoid doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
        doPost(request, response);
    }

protectedvoid doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
        List<VideoNews> news = vs.readNews();
        request.setAttribute("xmlnews", news);
        request.getRequestDispatcher("/WEB-INF/pages/newsxml.jsp").forward(request, response);
    }
}

<%@ page language="java"contentType="text/xml; charset=utf-8"pageEncoding="utf-8"%><%@ taglib prefix="c"uri="http://java.sun.com/jsp/jstl/core" %><?xmlversion="1.0"encoding="UTF-8"?>
<videoNews>
<c:forEachitems="${xmlnews}"var="n">
<newsid="${n.id }">
<title>${n.title }</title>
<length>${n.timeLength }</length>
</news>
</c:forEach>
</videoNews>

Android項目

publicclass VideoNewsServiceImpl implements VideoNewsService
{
/**
     * 獲取最新視頻資訊，從XML文件中，比較常用
     */
public List<VideoNews> getNewsFromXML() 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 = parseXML(instream);
        }
return lst;
    }

/**
     * 解析XML
     */
private List<VideoNews> parseXML(InputStream instream) throws Exception
    {
        List<VideoNews> lst = null;
        VideoNews vn = null;
// 利用ANDROID提供的API快速獲得pull解析器
        XmlPullParser pullParser = Xml.newPullParser();
// 設置需要解析的XML數據
        pullParser.setInput(instream, "UTF-8");
// 取得事件
int event = pullParser.getEventType();
// 若爲解析到末尾,文檔結束
while (event != XmlPullParser.END_DOCUMENT)
        {
            String nodeName = pullParser.getName();
switch (event)
            {
// 文檔開始
case XmlPullParser.START_DOCUMENT:
                    lst = new ArrayList<VideoNews>();
break;
// 標籤開始
case XmlPullParser.START_TAG:
if ("news".equals(nodeName))
                    {
                        vn = new VideoNews();
                        Integer id = Integer.valueOf(pullParser.getAttributeValue(0));
                        vn.setId(id);
                    }
if ("title".equals(nodeName))
                    {
                        String title = pullParser.nextText();
                        vn.setTitle(title);
                    }
if ("length".equals(nodeName))
                    {
                        Integer length = Integer.valueOf(pullParser.nextText());
                        vn.setTimeLength(length);
                    }
break;
// 標籤結束
case XmlPullParser.END_TAG:
if ("news".equals(nodeName))
                    {
                        lst.add(vn);
                        vn = null;
                    }
break;
            }
// 下一個標籤
            event = pullParser.next();
        }
return lst;
    }
}

最後把得到的數據綁定到ListView中即可。

本文出自 “IT徐胖子的專欄” 博客，請務必保留此出處http://woshixy.blog.51cto.com/5637578/1088051