commentaction.java

Ajax评论系统(结合Prototype+Freemarker分页)

package ajax.web.action;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.jsp.JspFactory;
import javax.servlet.jsp.PageContext;
import ajax.web.po.Comment;
import ajax.web.service.CommentService;
import ajax.util.Function;
import ajax.util.freemarker.FreemarkerTool;
import ajax.util.Page;

/**
 * 评论控制器
 * 路径: /comment
 * 
 * @author  陈智聪(<a href="mailto:[e-mail]">[e-mail]</a>)
 * @version 2.0 - 2009/02/10
 */
@SuppressWarnings("unused")
public class CommentAction extends HttpServlet {

	private static final long serialVersionUID = 1L;
	private Comment comment;
	private CommentService service;
	private static FreemarkerTool tool;
	private static Map<String, Object> map;
	private static JspFactory factory;
	private static PageContext pageContext;
	
	/**
	 * 构造方法
	 */
	public CommentAction() {
		super();
	}

	/**
	 * 初始化
	 */
	public void init() throws ServletException {
		tool = new FreemarkerTool();
		map = new HashMap<String, Object>();
		factory = JspFactory.getDefaultFactory();
		comment = new Comment();
		service = new CommentService();
	}
	
	/**
	 * destroy方法
	 */
	public void destroy() {
		super.destroy();
	}

	/**
	 * 发表评论
	 * @param request
	 * @param response
	 * @throws ServletException
	 * @throws IOException
	 */
	public void save(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		
		//简单判断
		String nickname = Function.toHTML(request.getParameter("nickname"));
		String content = Function.toHTML(request.getParameter("content"));
		if (nickname == null || "".equals(nickname) || content == null || "".equals(content)) {
			out.print("请填写昵称和内容!");
			out.flush();
			out.close();
			return;
		}
		
		//设置Comment对象
		comment.setNickname(nickname);
		comment.setContent(content);
		comment.setPostTime(Function.getDateTime());
		comment.setClientIP(request.getRemoteAddr());
		
		long timeMillis_Now = System.currentTimeMillis();
		//首先判断是否已经提交过评论，如果是，则10s后才允许再次评论
		Cookie[] allCookie=request.getCookies();//取出所有的Cookie   
		for(int i=0;i<allCookie.length;i++) {   
			if(allCookie[i].getName().equals("comment_freq")) {//得到所要的Cookie
				long time = new Long(allCookie[i].getValue());
				System.out.println(timeMillis_Now - time);
				if(timeMillis_Now - time < 10000) {//10s
					out.print("留言过于频繁");
					out.flush();
					out.close();
					return;
				}
			}
		}
		
		//插入数据库
		if (!service.addComment(comment)) {
			out.print("留言失败!");
			out.flush();
			out.close();
			return;
		}
		
		//记录访客IP入Cookie
		Cookie comment_freq = new Cookie("comment_freq", System.currentTimeMillis()+"");
		response.addCookie(comment_freq);
	}
	
	/**
	 * 删除评论
	 * @param request
	 * @param response
	 * @throws ServletException
	 * @throws IOException
	 */
	public void del(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		
		String id = request.getParameter("id");
		
		//防止机器攻击
		if(!"127.0.0.1".equals(request.getRemoteAddr())) {
			out.print("false");
			out.flush();
			out.close();
			System.out.print(request.getRemoteAddr() + "您无权删除，仅能在本地(127.0.0.1)删除！");
			return;
		}
		if(id == null || "".equals(id)) {
			out.print("false");
			out.flush();
			out.close();
			return;
		}
		
		int ID = 0;
		try {
			ID = Integer.parseInt(id);
		} catch (NumberFormatException e) {
			ID = -1;
		}
		
		//删除失败
		if (!service.delComment(ID)) {
			out.print("false");
			out.flush();
			out.close();
		}
	}
	
	/**
	 * 评论列表
	 * @param request
	 * @param response
	 * @throws ServletException
	 * @throws IOException
	 */
	public void list(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setHeader("Pragma","No-cache");
		response.setHeader("Cache-Control","no-cache");
		response.setDateHeader("Expires", 0);
		pageContext = factory.getPageContext(this, request, response, null, false, 2048, true);
		String path = request.getContextPath();
		
		int resultSize = service.getCommentRowCount();//记录总数
		String p = request.getParameter("p");//分页参数
		int curPage = 1;
		try {
			curPage = (p == null) ? 1  : Integer.parseInt(p);//取得页面中的参数--当前页
		} catch (NumberFormatException e) {
			curPage = -1;
			return;
		}
		Page page = new Page();//分页类模型
        page.setCurPage(curPage);//设置当前页
        page.setRowCount(resultSize);//设置记录总数
        page.countMaxPage();//计算总页数
        
        //取得相应的结果集（部分记录）
        List<Comment> commentList = service.getCommentList((curPage - 1)*page.getRowSize(), page.getRowSize());
        map.put("path", path);
        map.put("page", page);//设置分页属性
        map.put("commentList", commentList);
		tool.mergeFile("/comment_list.html", map, pageContext);
	}
	
	/**
	 * Get方法
	 * @param request
	 * @param response
	 * @throws ServletException
	 * @throws IOException
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		PrintWriter out = response.getWriter();
		response.setContentType("text/html");
		
		String act = request.getParameter("act");
		if (act == null || "".equals(act)) {
			return;
		} else if ("del".equals(act)) {
			del(request, response);
		} else if ("list".equals(act)) {
			list(request, response);
		} else {
			out.print("非法Get请求!");
			out.flush();
			out.close();
		}
	}

	/**
	 * Post方法
	 * @param request
	 * @param response
	 * @throws ServletException
	 * @throws IOException
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		PrintWriter out = response.getWriter();
		response.setContentType("text/html");
		
		String act = request.getParameter("act");
		if (act == null || "".equals(act)) {
			return;
		} else if ("save".equals(act)) {
			save(request, response);
		} else {
			out.print("非法Post请求!");
			out.flush();
			out.close();
		}
	}
}