一个jsp+AJAX评论系统第1/2页

答案：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=> * @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=> * @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.s

上一个：java去掉html标签 必须首先去掉双引号的正则
下一个：下载完成后页面不自动关闭的方法