Communication between Android and server in JSON format

Communication between Android and server in JSON format
Network Communication Json version
After adding a parameter to the path, return Json format data to the Android app.
Http: // 192.168.1.100: 8080/videonews/ListServlet? Format = json
If no parameter is added, xml format data is returned by default.
Public class VideoNewsService
{
/* Obtain server information */
Public static List GetJSONLastNews () throws Exception {
String path = "http: // 192.168.1.100: 8080/videonews/ListServlet? Format = json ";
URL url = new URL (path );
HttpURLConnection conn = (HttpURLConnection) url. openConnection ();
Conn. setConnectionTimeout (5000 );
Conn. setRequestMethod ("GET ");
If (conn. getResponseCode () = 200)
{
InputStream inStream = conn. getInputStream ();
Return parseJSON (inStream );


}
Return null;
}
/* Parse the JSON data returned by the server */
Private static List ParseXML (InputStream inStream)
{
List Newses = new ArrayList ();
Byte [] data = StreamTool. read (inStream );
String json = new String (data );
JSONArray array = new JSONArray (json );
For (int I = 0; I {
// Obtain the Json object
JSONObject jsonObject = array. getJSONObject (I );
News news = new News (jsonObject. getInt ("id"), jsonObject. getString ("title"), jsonObject. getInt ("timelength "));
Newses. add (news );
}
Return newses;

}



Main. xml
Android: layout_width = "fill_parent ";
Android: layout_height = "wrap_content"
Android: id = "@ + id/listView"
/>
Item. xml
Android: id = "@ + id/title"
>
Android: id = "@ + id/timelength"
>





Android mainActivity:
Super. onCreate (savedInstanceState );
SetContentView (R. layout. main );
ListView listview = (ListView) this. findViewById (R. id. listview );
List Videos = VideoNewsService. getJSONLastNews ();
List > Data = new ArrayList > ();
For (News news: videos)
{
HashMap Item = new HashMap ();
Item. put ("id", news. getId ());
Item. put ("title", news. getTitle ());
Item. put ("timelength", news. getTimelength ());
Data. add (item );
}
SimpleAdapter adapter = new SimpleAdapter (this, data, R. layout. item, new String [] {"title", "timelength"}, new int [] {R. id. title, R. id. timelength });
ListView. setAdapter (adapter );


Server
Web technology
1. Create a servlet
Json format
[{Id: 56, title: "XXX", timelength: 90}, {id: 16, title: "XXb", timelength: 30}]
Public class ListServlet extends HttpServlet
{
Private static final long serialVersionUID = 1L;
Private VideoNewsService service = new VideoNewsServiceBean ();
Protected void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
List Videos = service. getLastNews ();
String format = request. getParameter ("format ");
If ("json". equals (format ))
{
StringBuilder builder = new StringBuilder ();
Builder. append ('[');
For (News news: videos)
{
Builder. append ('{');
Builder. append ("id:"). append (news. getId (). append (',');
Builder. append ("title: \" "). append (news. getTitle (). append (" \ ","); // backslash escape
Builder. append ("timelength:"). append (news. getTimelength ());
Builder. append ("},");
}
Builder. deleteChatAt (builder. length ()-1 );
Builder. append (']');
Request. setAttribute ("json", builder. toString ());
Request. getRequestDispather ("/WEB-INF/page/jsonvideonews. jsp"). forward (request, response );
} Else
{
Request. setAttribute ("videos", videos );
Request. getRequestDispather ("/WEB-INF/page/videonews. jsp"). forward (request, response );
}
}
News class
Public class News
{
Private Integer id;
Private String title;
Private Integer timelength;
Public News (){}
Public News (Integer id, String title, Integer timelength)
{
This. id = id;
This. title = title;
This. timelength = timelength;
}
Public Integer getId ()
{
Return id;
}
Public void setId (Integer id)
{
This. id = id;
}
Public String getTitle ()
{
Return title;
}
Public void setTitle (String title)
{
This. title = title;
}
Public Integer getTimelength ()
{
Return timelength;
}
Public void setTimelength (Integer timelength)
{
This. timelength = timelength;
}
}
VideoNewsServiceBean // implementation class
Public class VideoNewsServiceBean implements VideoNewsService
{
Public List GetLastNews ()
{
List Newses = new ArrayList ();
Newses. add (new News (35, "Xi Yang", 90 ));
Newses. add (new News (12, "grey Wolf", 30 ));
Newses. add (new News (56, "Red Wolf", 40 ));
Return newses;
}
}
Public interface VideoNewsService
{
/* Obtain video information */
Public List GetLastNews ();
}

Jsonvideonews. jsp
<% @ Page language = "java" contentType = "text/plain; charset = UTF-8" pageEncoding = "UTF-8" % >$ {json}