showbbs.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.ArrayList;
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.BbsDao;
import com.data.Bbs;

public class showbbs extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public showbbs() {
		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";
		}
		System.out.println("indentity:"+indentity);
		
		String condition=request.getParameter("condition");
		
        String order=request.getParameter("order");
        StringBuffer sql=new StringBuffer();
        sql.append("select * from bbs ");
        //选择条件
        System.out.println(condition+order);
        boolean a=false;
        if(condition.equals("shot")){
        	sql.append("where bbshot=1 ");//精帖
        	a=true;
        }else
        if(condition.equals("putong")){
        	sql.append("where bbshot=0 ");//普通帖
            a=true;
        }
        
        //条件二
       int con;
       con=Integer.parseInt(request.getParameter("con2"));
       System.out.println("con:"+con); 
       
       if(con!=-1){
        	if(a){
        	 sql.append("and board_id="+con+" " );
            }else{
             sql.append("where board_id="+con+" ");	
            }
        }
        //排序方式
        if(order.equals("bbshits")){
        	sql.append("order by bbshits desc");//点击率
        }else
        if(order.equals("bbsrecount")){
        	sql.append("order by bbsrecount desc");//回复数量
        }else
        if(order.equals("bbsdata")){
        	sql.append("order by bbsdata desc");//发表时间
        }else
        if(order.equals("bbsredata")){
        	sql.append("order by bbsredata desc");//回复时间
        }
        
        //获取显示的页数
        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=10;
        
        //查询数据
        List rs=BbsDao.getBbsDao(sql.toString(), page, pageSize,cupage);
		//生成xml
		Bbs bbs=new Bbs();
		backInf.append("<bbss>");
		backInf.append("<indentity>"+indentity+"</indentity>");	
		Iterator it=rs.iterator();
		int totalpages=(Integer)it.next();
		backInf.append("<totalpages>"+totalpages+"</totalpages>");	
		int currentpage=(Integer)it.next();
		setCurrentPage(sess,currentpage);
		backInf.append("<currentpage>"+currentpage+"</currentpage>");
		int pagecounts=(Integer)it.next();
		backInf.append("<pagecounts>"+pagecounts+"</pagecounts>");
		
		//帖子信息的xml
		while(it.hasNext()){
			bbs=(Bbs)it.next();
			backInf.append("<bbs>");
			backInf.append("<bbs_id>"+bbs.getBbs_id()+"</bbs_id>");	//id		
		    backInf.append("<bbshot>"+bbs.getBbshot()+"</bbshot>");//点击率
		    backInf.append("<bbstopic>"+bbs.getBbstopic()+"</bbstopic>");//主题
		    backInf.append("<bbscontent>"+bbs.getBbscontent()+"</bbscontent>");//内容
		    backInf.append("<username>"+bbs.getUsername()+"</username>");//用户名
		    backInf.append("<bbsdata>"+bbs.getBbsdata()+"</bbsdata>");//发表日期
		    backInf.append("<bbsrecount>"+bbs.getBbsrecount()+"</bbsrecount>");//回复数量
		    backInf.append("<bbshits>"+bbs.getBbshits()+"</bbshits>");//点击率
		    backInf.append("<bbsrename>"+bbs.getBbsrename()+"</bbsrename>");//回复人
		    backInf.append("<board_id>"+bbs.getBoard_id()+"</board_id>");//版面id
		    backInf.append("<bbsredata>"+bbs.getBbsredata()+"</bbsredata>");//回复时间
		    backInf.append("</bbs>");  
		  
		    
		}
		backInf.append("</bbss>");
        out.print(backInf.toString());
		out.flush();
		out.close();
	}
//	保存当前页到session中
	public  void setCurrentPage(HttpSession sess,int currentPage){
		if(sess.getAttribute("currentPage")!=null){
			sess.removeAttribute("currentPage");
		}
		sess.setAttribute("currentPage", currentPage);
		System.out.print(currentPage+"设置当前页 ");
	}
	
	public void init() throws ServletException {
		// Put your code here
	}

}