Page 1/2 of a JSP + Ajax comment System

This is a simple comment system, using the JDOM (here using Jdom-b9), the instance uses JSP as the view, combined with Ajax (using prototype-1.4), Servlet and JavaBean as the background processing, use an XML file to store data.
1. The application directory structure is as follows:
Data
| -- Comment. xml
JS
| -- Prototype. js
| -- UFO. js (UTF-8 format)
CSS
| --Ufo.css
Images
| --Loading.gif
UFO. jsp (UTF-8 format)
WEB-INF
|-Lib
|-JDOM. Jar
|-Classes
...
|-Web. xml

/*************************************** ******
* Author: java619
* Time: 2007-02-14
**************************************** ******/

2. Background JavaBean commentbean. Java

/***//**
* <P> presence of aliens in the comment System </P>
* @ Author ceun
* Contact Author: <br>
* <A href = "mailto: ceun@163.com"> ceun </a> <br>
* @ Version 1.0 basic functions <br>
* Commentbean. Java
* Created on Jan 30,200 7 9:39:19 AM
*/
Package com. ceun. Bean;

Import java. Io. filewriter;
Import java. Io. ioexception;
Import java. Text. simpledateformat;
Import java. util. arraylist;
Import java. util. date;
Import java. util. List;
Import java. util. Random;

Import org. JDOM. CDATA;
Import org. JDOM. Document;
Import org. JDOM. element;
Import org. JDOM. jdomexception;
Import org. JDOM. text;
Import org. JDOM. Input. saxbuilder;
Import org. JDOM. Output. xmloutputter;

/***//**
* <P> encapsulate XML Operations </P>
* @ Author ceun
* Contact Author: <br>
* <A href = "mailto: ceun@163.com"> ceun </a> <br>
* @ Version 1.0 basic functions <br>
*/
Public class commentbean ...{
Private string filepath;

Private saxbuilder builder = NULL;

Private document DOC = NULL;

Public commentbean ()...{

}
/***//**
* Initialize the XML file path and load the file
**/
Public commentbean (string path )...{
This. filepath = path;
Builder = new saxbuilder ();
Try ...{
Doc = builder. Build (filepath );
} Catch (jdomexception e )...{
System. Out. Print ("the specified XML file cannot be found ");
E. printstacktrace ();
} Catch (ioexception e )...{
System. Out. Print ("the specified file cannot be found ");
E. printstacktrace ();
}
}
/***//**
* Add comments
* @ Param nikename comments nickname
* @ Param Comment comment
* @ Param attitude comments conclusion (yes-yes, no-No)
**/
Public String addcomment (string nikename, string comment, string attitude )...{
Element root = Doc. getrootelement ();

Element El = new element ("comment ");
Random Rand = new random ();
Int id = Rand. nextint (10000 );
El. setattribute ("ID", "comment _" + id );
El. setattribute ("attitude", attitude );

Element name = new element ("nikename ");
CDATA cname = new CDATA (nikename );
Name. addcontent (cname );

Element Data = new element ("data ");
CDATA ctext = new CDATA (comment );
Data. addcontent (ctext );

Simpledateformat format = new simpledateformat ("yyyy-mm-dd hh: mm: SS ");
Date = new date ();
Text tdate = new text (format. Format (date ));
Element pubdate = new element ("pubdate ");
Pubdate. addcontent (tdate );

El. addcontent (name );
El. addcontent (data );
El. addcontent (pubdate );
Root. addcontent (EL );
Xmloutputter outputter = new xmloutputter ("", true, "gb2312 ");
// Clear spaces between comment Elements
Outputter. settrimallwhite (true );
Try ...{
Outputter. Output (Doc, new filewriter (filepath ));
} Catch (ioexception e )...{
System. Out. println ("the specified path is incorrect ");
E. printstacktrace ();
}
Return tdate. gettext ();
}
/***//**
* Delete A comment with a specified ID
* @ Param commentid comment ID
* @ Return returns the operation result string (successful or failed)
**/
Public String removecomment (string commentid )...{
Element root = Doc. getrootelement ();
List comments = root. getchildren ();
Int size = comments. Size ();
Element Dist = NULL;
For (INT I = 0; I <size; I ++ )...{
Element comment = (element) comments. Get (I );
String id = comment. getattributevalue ("ID ");
If (Id. Equals (commentid ))...{
Dist = comment;
Break;
}
}
If (Dist! = NULL )...{
Root. removecontent (DIST );
Xmloutputter outputter = new xmloutputter ("", true, "gb2312 ");
// Clear spaces between comment Elements
Outputter. settrimallwhite (true );
Try ...{
Outputter. Output (Doc, new filewriter (filepath ));
} Catch (ioexception e )...{
System. Out. println ("An error occurred while rewriting the file ");
E. printstacktrace ();
}
Return "the specified element is deleted successfully! ";
} Else
Return "the specified element does not exist! ";
}
/***//**
* Batch delete comments
* @ Param commentidargs comment ID Array
* @ Return returns the operation result string (successful or failed)
**/
Public String removecomments (string [] commentidargs )...{
Element root = Doc. getrootelement ();
List comments = root. getchildren ();
Int size = comments. Size ();
Int Len = commentidargs. length;
List <element> Dist = new arraylist <element> ();
Outer: For (INT I = 0; I <size; I ++ )...{
Element comment = (element) comments. Get (I );
String id = comment. getattributevalue ("ID ");

For (Int J = 0; j <Len; j ++)
If (Id. Equals (commentidargs [J])... {
Dist. Add (comment );
Continue outer;
}
}
Int dist_size = DIST. Size ();
If (dist_size! = 0 )...{
For (INT I = 0; I <dist_size; I ++)
Root. removecontent (Dist. Get (I ));
Xmloutputter outputter = new xmloutputter ("", true, "gb2312 ");
// Clear spaces between comment Elements
Outputter. settrimallwhite (true );
Try ...{
Outputter. Output (Doc, new filewriter (filepath ));
} Catch (ioexception e )...{
System. Out. println ("An error occurred while rewriting the file ");
E. printstacktrace ();
}
Return "the specified Element Set is deleted successfully! ";
} Else
Return "the specified Element Set does not exist! ";
}

/***//**
* @ Return the filepath
*/
Public String getfilepath ()...{
Return filepath;
}

/***//**
* @ Param filepath
* The filepath to set
*/
Public void setfilepath (string filepath )...{
This. filepath = filepath;
}

/***//**
* @ Return the Builder
*/
Public saxbuilder getbuilder ()...{
Return builder;
}

/***//**
* @ Param Builder
* The builder to set
*/
Public void setbuilder (saxbuilder builder )...{
This. Builder = builder;
}
}

3. servlet addcommentservlet. Java for processing Ajax requests

Package com. ceun. servlet;

Import java. Io. ioexception;
Import java. Io. printwriter;

Import javax. servlet. servletexception;
Import javax. servlet. http. httpservlet;
Import javax. servlet. http. httpservletrequest;
Import javax. servlet. http. httpservletresponse;

Import com. ceun. Bean. commentbean;
/***//**
* <P> backend processing servlet </P>
* 2007-01-30
** @ Author ceun
* Contact Author: <br>
* <A href = "mailto: ceun@163.com"> ceun </a> <br>
* @ Version 1.0 basic functions <br>
**/
Public class addcommentservlet extends httpservlet ...{

/***//**
* Serialversionuid long
*/
Private Static final long serialversionuid = 1l;

/***//**
* The doget method of the servlet. <br>
*
* This method is called when a form has its tag Value Method equals to get.
*
* @ Param request
* The request send by the client to the server
* @ Param response
* The response send by the server to the client
* @ Throws servletexception
* If an error occurred
* @ Throws ioexception
* If an error occurred
*/
Public void doget (httpservletrequest request, httpservletresponse response)
Throws servletexception, ioexception ...{
Request. setcharacterencoding ("UTF-8 ");
Response. setcontenttype ("text/html; charset = UTF-8 ");
Response. setheader ("cache-control", "No-Cache ");

Printwriter out = response. getwriter ();
String nikename = request. getparameter ("Nn ");

String comment = request. getparameter ("RSN ");
String attitude = request. getparameter ("atti ");
String filepath = request. getsession (). getservletcontext (). getrealpath (
"Data/comment. xml ");
Commentbean bean = new commentbean (filepath );
String STR = bean. addcomment (nikename, comment, attitude );
Out. println (STR );
}

/***//**
* The dopost method of the servlet. <br>
*
* This method is called when a form has its tag Value Method equals
* Post.
*
* @ Param request
* The request send by the client to the server
* @ Param response
* The response send by the server to the client
* @ Throws servletexception
* If an error occurred
* @ Throws ioexception
* If an error occurred
*/
Public void dopost (httpservletrequest request, httpservletresponse response)
Throws servletexception, ioexception ...{

Doget (request, response );
}

}