这是一个简单的评论系统,使用了JDOM(这边使用Jdom-b9),实例使用JSP作为视图,结合使用AJAX(用到prototype-1.4),Servlet和JavaBean作为后台处理，使用xml文件存储数据。
1.应用目录结构如下:
data
|--comment.xml
js
|--prototype.js
|--ufo.js(UTF-8格式)
css
|--ufo.css
images
|--loading.gif
ufo.jsp(UTF-8格式)
WEB-INF
|-lib
|-jdom.jar
|-classes
...
|-web.xml
/*********************************************
*Author:Java619
*Time:2007-02-14
**********************************************/

2.后台JavaBean CommentBean.java
/** *//**
* <P>外星人是否存在评论系统</p>
* @author ceun
* 联系作者:<br>
* <a href="mailto:[email protected]">ceun</a><br>
* @version 1.0 2007-01-30 实现基本功能<br>
* CommentBean.java
* Created on Jan 30, 2007 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> 封装对XML的操作</p>
* @author ceun
* 联系作者:<br>
* <a href="mailto:[email protected]">ceun</a><br>
* @version 1.0 2007-01-30 实现基本功能<br>
*/
public class CommentBean ...{
private String filepath;
private SAXBuilder builder = null;
private Document doc = null;
public CommentBean() ...{
}
/** *//**
* 初始化XML文件路径,加载文件
* */
public CommentBean(String path) ...{
this.filepath = path;
builder = new SAXBuilder();
try ...{
doc = builder.build(filepath);
} catch (JDOMException e) ...{
System.out.print("找不到指定的XML文件");
e.printStackTrace();
} catch (IOException e) ...{
System.out.print("找不到指定的文件");
e.printStackTrace();
}
}
/** *//**
* 添加评论
* @param nikename 评论者昵称
* @param comment 评论内容
* @param attitude 评论者的结论(yes-存在,no-不存在)
* */
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 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");
// 清除comment元素间的空格
outputter.setTrimAllWhite(true);
try ...{
outputter.output(doc, new FileWriter(filepath));
} catch (IOException e) ...{
System.out.println("指定路径有错");
e.printStackTrace();
}
return tdate.getText();
}
/** *//**
* 删除指定ID的评论
* @param commentId 评论ID
* @return 返回操作结果字符串(成功或失败)
* */
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");
// 清除comment元素间的空格
outputter.setTrimAllWhite(true);
try ...{
outputter.output(doc, new FileWriter(filepath));
} catch (IOException e) ...{
System.out.println("重写文件有出错");
e.printStackTrace();
}
return "成功删除指定元素!";
} else
return "指定元素不存在!";
}
/** *//**
* 批量删除评论
* @param commentIdArgs 评论ID数组
* @return 返回操作结果字符串(成功或失败)
* */
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");
// 清除comment元素间的空格
outputter.setTrimAllWhite(true);
try ...{
outputter.output(doc, new FileWriter(filepath));
} catch (IOException e) ...{
System.out.println("重写文件有出错");
e.printStackTrace();
}
return "成功删除指定的元素集合!";
} else
return "指定元素集合的不存在!";
}
/** *//**
* @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.处理AJAX请求的Servlet AddCommentServlet.java
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>后台处理Servlet</p>
*2007-01-30
* * @author ceun
* 联系作者:<br>
* <a href="mailto:[email protected]">ceun</a><br>
* @version 1.0 2007-01-30 实现基本功能<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(
"/upload/tech/20091011/20091011155513_854d9fca60b4bd07f9bb215d59ef5561.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 to
* 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);
}
}

4.JSP视图 ufo.jsp
<%...@ page contentType="text/html;charset=UTF-8"%>
<%...
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh_CN" lang="zh_CN">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta http-equiv="pragma" content="no-cache" />
<meta http-equiv="cache-control" content="no-cache" />
<meta http-equiv="expires" content="0" />
<title>ufo</title>
<link rel="stylesheet" type="text/css" href="css/ufo.css"/>
<script src="<%=basePath%>js/prototype.js" type="text/javascript"></script>
<script src="<%=basePath%>js/ufo.js" type="text/javascript"></script>
</head>
<SCRIPT type="text/javascript">...
<!--
window.onload=function()...{
getComments("<%=basePath%>/upload/tech/20091011/20091011155513_854d9fca60b4bd07f9bb215d59ef5561.xml");
}
//-->
</SCRIPT>
<body>
<div id="cinfoDiv" style="display:none;">
<h2>
信息提示
</h2>
<p id="cinfomsg">
</p>
</div>
<table id="process-indicator"
style="display:none;z-index:100;width:300px;">
<tr>
<td>
<img src="/upload/tech/20091011/20091011155514_23ce1851341ec1fa9e0c259de10bf87c.gif" />
<p>
正在处理中...
</p>
</td>
</tr>
</table>
<center>
<div id="comment-lists">
</div>
<div id="comment">
<div style="display:none;top:100px;left:200px;" id="locateDiv1">
</div>
<div id="comment-bar">
你认为外星人存在吗?
</div>
<div id="comment-form">
<form onsubmit="return false;" name="cform">
昵称:
<input type="text" id="nn" name="nn" />
<input type="radio" id="exist" name="exist" value="yes" />
存在
<input type="radio" id="exist" name="exist" value="no" />
不存在
<br />
<textarea name="reason" style="width: 480px;height:200px;"
id="reason"></textarea>
<button id="btnsubmit" class="button"
onclick="addComment('<%=path%>/addCommentServlet');">
发表你的看法
</button>
<input type="reset" id="btnreset" class="button" />
</form>
</div>
</div>
</center>
</body>
</html>
5.前台脚本 ufo.js
var Browser = ...{};
Browser.isMozilla = (typeof document.implementation !=
"undefined") && (typeof document.implementation.createDocument != "undefined") && (typeof HTMLDocument != "undefined");
Browser.isIE = window.ActiveXObject ? true : false;
Browser.isFirefox = (navigator.userAgent.toLowerCase().indexOf("firefox") != -1);
Browser.isSafari = (navigator.userAgent.toLowerCase().indexOf("safari") != -1);
Browser.isOpera = (navigator.userAgent.toLowerCase().indexOf("opera") != -1);
String.prototype.trim=function()...{return this.replace(/^s+|s+$/g,"");};
function addComment(url)...{
var nn=$F("nn");
var rsn=$F("reason");
var atti=false;
var rbgroup=document.cform.elements["exist"];
for(i=0;i<rbgroup.length;i++)...{
if(rbgroup[i].checked) ...{atti=rbgroup[i].value;break;};
}
var locateTop=$("locateDiv1").parentNode.offsetTop-50;
var locateLeft=$("locateDiv1").parentNode.offsetLeft+150;
var alertMsg="";
if(!atti)
alertMsg+="<br/>请表明你的态度!";
if(nn.trim()=="")
alertMsg+="<br/>昵称不能为空!"
if(rsn.trim()=="")
alertMsg+="<br/>请写下你的理由!";
var cinfomsg=$("cinfomsg");
if(alertMsg!="")...{
cinfomsg.className="failure";
cinfomsg.innerHTML=alertMsg;
showDialog($("cinfoDiv"),locateTop,locateLeft);
return;
}else...{
cinfomsg.className="success";
cinfomsg.innerHTML="正处理数据中...";
showDialog($("cinfoDiv"),locateTop,locateLeft);
}
var pars="nn="+nn+"&atti="+atti+"&rsn="+rsn;
var http=Ajax.getTransport();
var contentType = "application/x-www-form-urlencoded; charset=utf-8";
http.open("POST",url,true);
http.setRequestHeader("Content-Type", contentType);
http.onreadystatechange=function()...{
if (http.readyState == 4)...{
if (http.status==200)...{
afterAdd(http);
}
}
}
http.send(pars);
}
function afterAdd(request)...{
hideDialog();
var atti=false;
var rbgroup=document.cform.elements["exist"];
for(i=0;i<rbgroup.length;i++)...{
if(rbgroup[i].checked) ...{atti=rbgroup[i].value;break;};
}
var nn=$F("nn");
var rsn=$F("reason");
generateCommentList(atti,nn,request.responseText,rsn)
$("nn").value="";
$("reason").value="";
}
function generateCommentList(atti,nn,date,rsn)...{
var commentLists=$("comment-lists");
var commentlist=document.createElement("div");
commentlist.className="comment-list";
var observerInfo=document.createElement("div");
observerInfo.className="observer-info";
var attitude=(atti=="yes")?"认为存在":"认为不存在";
var info=document.createTextNode("评论者:"+nn+" 观点:"+attitude+" "+date);
observerInfo.appendChild(info);
var observerComment=document.createElement("div");
observerComment.className="observer-comment";
var reason=document.createTextNode(rsn);
observerComment.appendChild(reason);
commentlist.appendChild(observerInfo);
commentlist.appendChild(observerComment);
if(commentLists.hasChildNodes())...{
var tmp=commentLists.firstChild;
commentLists.insertBefore(commentlist,tmp);
}else
commentLists.appendChild(commentlist);
}
function getComments(url)...{
Element.show("process-indicator");
Element.makePositioned("process-indicator");
var top = document.body.scrollTop + 200;
var left = "";
if ($("process-indicator").style.width) ...{
left =window.document.body.scrollWidth/2-100;
} else ...{
left = parseInt(document.body.clientWidth / 2);
}
var style = ...{top:top + "px", left:left + "px"};
Element.setStyle("process-indicator", style);
//加个随机数,去除缓存影响
var pars="rd=rd_"+parseInt(Math.random()*10000);
var http=Ajax.getTransport();
var contentType = "application/x-www-form-urlencoded; charset=utf-8";
http.open("POST",url,true);
http.setRequestHeader("Content-Type", contentType);
http.onreadystatechange=function()...{
if (http.readyState == 4)...{
if (http.status==200)...{
afterGetComments(http);
}
}
}
http.send(pars);
}
function afterGetComments(request)...{
//提示框
Element.hide("process-indicator");
var xmldata=request.responseXML;
var comments=xmldata.getElementsByTagName("comment");
if(!comments)...{alert("暂无评论");return;}
var len=comments.length;
for(var i=0;i<len;i++)...{
var atti=comments[i].getAttribute("attitude");
var nn=comments[i].getElementsByTagName("nikename")[0].firstChild.nodeValue;
var rsn=comments[i].getElementsByTagName("data")[0].firstChild.nodeValue;
var date=comments[i].getElementsByTagName("pubdate")[0].firstChild.nodeValue;
generateCommentList(atti,nn,date,rsn)
}
}
//对话框模块
var lastDialog=null;
function showDialog(dialog,offsetTop,offsetLeft)...{
if (lastDialog) lastDialog.style.display="none";
dialog.style.top=offsetTop+"px";
dialog.style.left=offsetLeft+"px";
dialog.style.display="";
lastDialog=dialog;
document.onmousedown=toHideDialog
}
function toHideDialog(event)...{
if (!lastDialog) ...{document.onclick=null;return;}
var obj=null;
if(Browser.isIE) obj=window.event.srcElement;
else obj=event.target;
hideDialog();
}
function hideDialog()...{
if (lastDialog) lastDialog.style.display="none";
lastDialog=null
document.onmousedown=null;
}
6.CSS ufo.css
#comment{...}{
background-color: InactiveCaptionText;
width: 550px;
height:300px;
margin-top:10px;
}
#comment-bar{...}{
color:white;
padding-top: 5px;
padding-bottom: 5px;
text-align: center;
background-color: ActiveCaption;
}
#comment-form{...}{
padding-left:20px;
}
.button{...}{
BORDER-RIGHT: #283043 1px solid; PADDING-RIGHT: 1px; BORDER-TOP: #9097a2 1px solid;
PADDING-LEFT: 1px; BACKGROUND: ActiveCaption;; PADDING-BOTTOM: 1px;
BORDER-LEFT: #9097a2 1px solid; COLOR: #fff;
PADDING-TOP: 1px; BORDER-BOTTOM: #283043 1px solid;
margin: 10px;
}
#comment-lists{...}{
background-color: InactiveCaptionText;
width: 550px;
margin-bottom:10px;
}
div.comment-list{...}{
text-align: left;
border:1px solid ActiveCaption;
margin: 5px;
}
div.observer-info{...}{
color:white;
padding-top: 5px;
padding-bottom: 5px;
padding-left: 5px;
text-align: left;
background-color: ActiveCaption;
font-size: 14px;
}
div.observer-comment{...}{
padding-top: 5px;
padding-bottom: 5px;
text-align: left;
}
#process-indicator{...}{
margin:10px;padding-top:15px;padding-right:5px;padding-left:5px;
background-color:cyan;position:absolute;border:2px solid ActiveCaption;
}
.success {...}{
COLOR: Blue;
}
.failure {...}{
COLOR: #ff665b
}
#cinfoDiv {...}{
position:absolute;
top:10px;
width:200px;
height:120px;
z-index:1000;
background-color:#F0F8FF;
border:1px solid #009999
}
#cinfoDiv h2{...}{
background-color:#483D8B;
font-size:14px;
color:#fff;
text-align:center;
margin-top:0px;
}
#cinfoDiv p{...}{
margin:5px;
text-align:center;
vertical-align: top;
font-size:14px;
}
7.comment.xml

<?xml version="1.0" encoding="GB2312"?>
<comments>
<comment id="comment_4119" attitude="yes">
<nikename><![CDATA[薜荔女萝衣]]></nikename>
<data><![CDATA[这个问题要全面分析。
外星很简单，相对于地球之外而言。
人吗，就给这个生物一个限定性标准了，至少要像人啊。
存在本身就是一个问题。谁能证明存在是存在的呢？
谁又能全面地证明存在是不存在的呢？类似高尔吉亚的智者派的方法就不要再用了。
之后才要探讨是与否的问题。
]]></data>
<pubdate>2007-01-31 20:53:33</pubdate>
</comment>
<comment id="comment_5953" attitude="yes">
<nikename><![CDATA[ぁあ宇宙过客]]></nikename>
<data><![CDATA[肯定会存在，难道真么大一个宇宙就只有地球有生物？
]]></data>
<pubdate>2007-01-31 20:56:17</pubdate>
</comment>
<comment id="comment_2199" attitude="yes">
<nikename><![CDATA[匿名]]></nikename>
<data><![CDATA[存在。如果没有的话怎么会在恐龙的肚子中找到一个相似外星化石呢？]]></data>
<pubdate>2007-01-31 21:00:43</pubdate>
</comment>
<comment id="comment_8637" attitude="yes">
<nikename><![CDATA[互相帮助小组]]></nikename>
<data><![CDATA[有高等智慧生物吧，但不一定是人的形势啊！我坚信它们的存在。]]></data>
<pubdate>2007-01-31 21:03:21</pubdate>
</comment>
<comment id="comment_237" attitude="yes">
<nikename><![CDATA[秦国园林]]></nikename>
<data><![CDATA[我就是外星人,我乘坐的大型飞行器----地球,不知什么时侯回到我的家乡----宇宙的起点.
自从人类产生就和那失去了联系,你能告诉我航行的方向吗?船长先生.
]]></data>
<pubdate>2007-01-31 21:11:06</pubdate>
</comment>
</comments>

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