Android之从网络中获取数据并返回客户端的两种方式:XML格式返回与Json格式返回

http://daimajishu.iteye.com/blog/1088626

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Android之从网络中获取数据并返回客户端的两种方式:XML格式返回与Json格式返回

jsonXMLAndroid网络协议资讯

1.服务器端代码样例：

public class VideoListAction extends Action
{
    private VideoService service = new VideoServiceBean();
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response)
            throws Exception
    {
        //得到最新的视频资讯
        List<Video> videos = service.getLastVideos();
        VideoForm formbean = (VideoForm)form;
        if("json".equals(formbean.getFormat()))
        {
            //构建json字符串
            StringBuilder json = new StringBuilder();
            json.append('[');
            for(Video video : videos)
            { // 需要构造的形式是{id:76,title:"xxxx",timelength:80}
                json.append('{');
                json.append("id:").append(video.getId()).append(',');
                json.append("title:\"").append(video.getTitle()).append("\",");
                json.append("timelength:").append(video.getTime());
                json.append('}').append(',');
            }
            json.deleteCharAt(json.length()-1);
            json.append(']');
            //把json字符串放置于request
            request.setAttribute("json", json.toString());
            return mapping.findForward("jsonvideo");
        }
        else
        {
            request.setAttribute("videos", videos);
            return mapping.findForward("video");
        }
    }
}

public class VideoServiceBean implements VideoService
{
    public List<Video> getLastVideos() throws Exception
    {
        //理论上应该查询数据库
        List<Video> videos = new ArrayList<Video>();
        videos.add(new Video(78, "喜羊羊与灰太狼全集", 90));
        videos.add(new Video(78, "实拍舰载直升东海救援演习", 20));
        videos.add(new Video(78, "喀麦隆VS荷兰", 30));
        return videos;
    }
}

public class VideoListAction extends Action
{
    private VideoService service = new VideoServiceBean();
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response)
            throws Exception
    {
        //得到最新的视频资讯
        List<Video> videos = service.getLastVideos();
        VideoForm formbean = (VideoForm)form;
        if("json".equals(formbean.getFormat()))
        {
            //构建json字符串
            StringBuilder json = new StringBuilder();
            json.append('[');
            for(Video video : videos)
            { // 需要构造的形式是{id:76,title:"xxxx",timelength:80}
                json.append('{');
                json.append("id:").append(video.getId()).append(',');
                json.append("title:\"").append(video.getTitle()).append("\",");
                json.append("timelength:").append(video.getTime());
                json.append('}').append(',');
            }
            json.deleteCharAt(json.length()-1);
            json.append(']');
            //把json字符串放置于request
            request.setAttribute("json", json.toString());
            return mapping.findForward("jsonvideo");
        }
        else
        {
            request.setAttribute("videos", videos);
            return mapping.findForward("video");
        }
    }
}

2.客户端：使用XML方式与JSON方式返回数据

public class VideoService
{
    /**
     * 以XML方式返回获取最新的资讯
     * @return
     * @throws Exception
     */
    public static List<Video> getLastVideos() throws Exception
    {
        //确定请求服务器的地址
        //注意在Android模拟器中访问本机服务器时不可以使用localhost与127字段
        //因为模拟器本身是使用localhost绑定
        String path = "http://192.168.1.100:8080/videoweb/video/list.do";
        //建立一个URL对象
        URL url = new URL(path);
        //得到打开的链接对象
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        //设置请求超时与请求方式
        conn.setReadTimeout(5*1000);
        conn.setRequestMethod("GET");
        //从链接中获取一个输入流对象
        InputStream inStream = conn.getInputStream();
        //对输入流进行解析
        return parseXML(inStream);
    }

    /**
     * 解析服务器返回的协议，得到资讯
     * @param inStream
     * @return
     * @throws Exception
     */
    private static List<Video> parseXML(InputStream inStream) throws Exception
    {
        List<Video> videos = null;
        Video video = null;
        //使用XmlPullParser
        XmlPullParser parser = Xml.newPullParser();
        parser.setInput(inStream, "UTF-8");
        int eventType = parser.getEventType();//产生第一个事件
        //只要不是文档结束事件
        while(eventType!=XmlPullParser.END_DOCUMENT)
        {
            switch (eventType)
            {
                case XmlPullParser.START_DOCUMENT:
                    videos = new ArrayList<Video>();
                    break;

                case XmlPullParser.START_TAG:
                    //获取解析器当前指向的元素的名称
                    String name = parser.getName();
                    if("video".equals(name))
                    {
                        video = new Video();
                        //把id属性写入
                        video.setId(new Integer(parser.getAttributeValue(0)));
                    }
                    if(video!=null)
                    {
                        if("title".equals(name))
                        {
                            //获取解析器当前指向元素的下一个文本节点的值
                            video.setTitle(parser.nextText());
                        }
                        if("timelength".equals(name))
                        {
                            //获取解析器当前指向元素的下一个文本节点的值
                            video.setTime(new Integer(parser.nextText()));
                        }
                    }
                    break;

                case XmlPullParser.END_TAG:
                    if("video".equals(parser.getName()))
                    {
                        videos.add(video);
                        video = null;
                    }
                    break;
            }
            eventType = parser.next();
        }
        return videos;
    }

    /**
     * 以Json方式返回获取最新的资讯，不需要手动解析，JSON自己会进行解析
     * @return
     * @throws Exception
     */
    public static List<Video> getJSONLastVideos() throws Exception
    {
        //
        List<Video> videos = new ArrayList<Video>();
        //
        String path = "http://192.168.1.100:8080/videoweb/video/list.do?format=json";
        //建立一个URL对象
        URL url = new URL(path);
        //得到打开的链接对象
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        //设置请求超时与请求方式
        conn.setReadTimeout(5*1000);
        conn.setRequestMethod("GET");
        //从链接中获取一个输入流对象
        InputStream inStream = conn.getInputStream();
        //调用数据流处理方法
        byte[] data = StreamTool.readInputStream(inStream);
        String json = new String(data);
        //构建JSON数组对象
        JSONArray array = new JSONArray(json);
        //从JSON数组对象读取数据
        for(int i=0 ; i < array.length() ; i++)
        {
            //获取各个属性的值
            JSONObject item = array.getJSONObject(i);
            int id = item.getInt("id");
            String title = item.getString("title");
            int timelength = item.getInt("timelength");
            //构造的对象加入集合当中
            videos.add(new Video(id, title, timelength));
        }
        return videos;
    }
}

public class StreamTool
{
    /**
     * 从输入流中获取数据
     * @param inStream 输入流
     * @return
     * @throws Exception
     */
    public static byte[] readInputStream(InputStream inStream) throws Exception{
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while( (len=inStream.read(buffer)) != -1 ){
            outStream.write(buffer, 0, len);
        }
        inStream.close();
        return outStream.toByteArray();
    }
}

public class MainActivity extends Activity
{
    private ListView listView;
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //获取到ListView对象
        listView = (ListView)this.findViewById(R.id.listView);
        try
        {
            //通过
            List<Video> videos = VideoService.getLastVideos();
            //通过Json方式获取视频内容
            //List<Video> videos2 = VideoService.getJSONLastVideos();
            //
            List<HashMap<String, Object>> data = new ArrayList<HashMap<String,Object>>();
            //迭代传入
            for(Video video : videos)
            {
                //把video中的数据绑定到item中
                HashMap<String, Object> item = new HashMap<String, Object>();
                item.put("id", video.getId());
                item.put("title", video.getTitle());
                item.put("timelength", "时长:"+ video.getTime());
                data.add(item);
            }
            //使用SimpleAdapter处理ListView显示数据
            SimpleAdapter adapter = new SimpleAdapter(this, data, R.layout.item,
                    new String[]{"title", "timelength"}, new int[]{R.id.title, R.id.timelength});
            //
            listView.setAdapter(adapter);
        }
        catch (Exception e)
        {
            Toast.makeText(MainActivity.this, "获取最新视频资讯失败", 1).show();
            Log.e("MainActivity", e.toString());
        }
    }
}