showboard.java

在学校做的第一个jsp专周论坛,用了些ajax技术.

package com.service;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.dao.*;
import com.data.*;

public class showboard extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public showboard() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}


	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	    
		response.setContentType("text/xml;charset=utf-8");
		response.setHeader("Cache-Control","no-cache"); 
		PrintWriter out = response.getWriter();
		request.setCharacterEncoding("UTF-8");
		StringBuffer backInf=new StringBuffer();
		HttpSession sess=request.getSession(true);
		
		String indentity=null;
		indentity=(String)sess.getAttribute("indentity");
		if(indentity==null){
			indentity="yonghu";
		}
		
		
		String order=request.getParameter("order");//读取排行方式
		StringBuffer sql=new StringBuffer();
        sql.append("select * from board ");
        if(order.equals("boardhits")){//版面点击率
        	sql.append("order by boardhits desc");
        }else
        if(order.equals("boardtopics")){//版面主题目数
        	sql.append("order by boardtopics desc");
        }
       //分页处理
        int page=Integer.parseInt(request.getParameter("page"));
        //int pageSize=Integer.parseInt((String)sess.getAttribute("pageSize"));
        int cupage=0;
        if(page==-2||page==-3){
        	
        	cupage=(Integer)sess.getAttribute("currentPage");
        	
        }
        int pageSize=15;
        
        System.out.println("sql:"+sql.toString());
        List rs=BoardDao.getBoardDao(sql.toString(), page, pageSize,cupage);
		System.out.println("获取的记录为："+rs.size());
		Boards board=new Boards();
		//将结果表示成xml格式，客户端用js解析
		backInf.append("<boards>");
		backInf.append("<indentity>"+indentity+"</indentity>");	//用户身份
		Iterator it=rs.iterator();
		int totalpages=(Integer)it.next();
		backInf.append("<totalpages>"+totalpages+"</totalpages>");	//总页数目
		int currentpage=(Integer)it.next();
		setCurrentPage(sess,currentpage);
		backInf.append("<currentpage>"+currentpage+"</currentpage>");//当前页数
		int pagecounts=(Integer)it.next();
		backInf.append("<pagecounts>"+pagecounts+"</pagecounts>");//当前页的数量
		
		System.out.println("totalpages:"+totalpages+"currentpage:"+currentpage+"pagecounts:"+pagecounts);
		
		while(it.hasNext()){
			board=(Boards)it.next();
			//版面信息
			backInf.append("<bbs>");
			backInf.append("<board_id>"+board.getBoard_id()+"</board_id>");			
		    backInf.append("<boardname>"+board.getBoardname()+"</boardname>");//版名
		    backInf.append("<boardmaster>"+board.getBoardmaster()+"</boardmaster>");//版主名;
		    backInf.append("<masterword>"+board.getMasterword()+"</masterword>");//版主格言
		    backInf.append("<masteremail>"+board.getMasteremail()+"</masteremail>");//版主email
		    backInf.append("<boardhits>"+board.getBoardhits()+"</boardhits>");//版主点击率
		    backInf.append("<boardtopics>"+board.getBoardtopics()+"</boardtopics>");//主题
		    backInf.append("</bbs>");  
		    System.out.print("board.getBbs_id()"+board.getBoardname());
		    
		}
		backInf.append("</boards>");
        out.print(backInf.toString());
        out.flush();
		out.close();
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occure
	 */ 
	//保存当前页到session中
	public  void setCurrentPage(HttpSession sess,int boardPage){
		if(sess.getAttribute("boardPage")!=null){
			sess.removeAttribute("boardPage");
		}
		sess.setAttribute("boardPage", boardPage);
		System.out.print(boardPage+"设置当前页 ");
	}
	
	public void init() throws ServletException {
		// Put your code here
	}

}