在JSP页面中实现检索数据的分页显示

querymedicine. java (Medicine. querymedicine) 

package Medicine; 

import javax.servlet.*; 

import javax.servlet.http.*; 

import java.io.*; 

import java.util.*; 

import java.sql.*; 

import Medicine.medicinelist; 

import Medicine.searchData; 

//////////////////////////////////////////////////// 

// 接---mutiquery.jsp页面，并从request中得到5条查询条件 /// 

// 按条件查询药品，并将结果存进session的“medicinelist”中。 /// 

// 张乾 2000年3月15日 /// 

//////////////////////////////////////////////////// 

public class querymedicine extends HttpServlet { 

private DBConnectionManager connMgr; 

//Initialize global variables 

public void init(ServletConfig config) throws ServletException { 

super.init(config); 

connMgr = DBConnectionManager.getInstance(); 

} 

//========================处理 HTTP Get 请求============================ 

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

Statement stmt=null; 

Connection con = connMgr.getConnection("medicine"); 

if (con == null) { 

response.sendRedirect("/medicine/con_error.html"); 

return; 

} 

// ==================== 创建数据库Statement ============================= 

try { 

stmt=con.createStatement(); 

} 

catch (Exception e) 

{ 

connMgr.freeConnection("medicine",con); 

response.sendRedirect("/medicine/stmt_error.html"); 

return; 

} 

//------------------------------------------------------------- 

long all_count=0; //存满足条件的药品总数 

//===================从request中得到session====================== 

try{ 

HttpSession session = request.getSession(false); 

if (session == null) { 

connMgr.freeConnection("medicine",con); 

response.sendRedirect("/medicine/session_error.html"); 

return; 

} 

//----------------------------------------------------------- 

//======从“下一页”提交来的参数取得前页最后一条数据的药品编码======= 

String ll_pos=request.getParameter("pos"); 
//如果pos=-1则表示要从头开始查 

//---------------------------------------------------------- 

//=====================查询用的SQL语句串========================== 

String sqlstatment="SELECT medicines.ypbm, medsmalltypes.zlmc, 
medsupertypes.clmc, 
medtypes.dlmc, medicines.ypm, medicines.zyyx, medicines.ypzy 
FROM medicines, 
medsmalltypes,medsupertypes,medtypes WHERE medicines.ypbm>"+ll_pos+" 
and (( medsmalltypes.zlbm = medicines.zlbm ) and 
( medsupertypes.clbm = medicines.clbm ) 
and ( medtypes.dlbm = medicines.dlbm ) and ( ( medicines.del_flag = 0 ) "; 

//----------------------------------------------------- 

String zlbm; 

String dlbm; 

String clbm; 

String zyyx; 

String ypm; 

searchData slist=new searchData(); 

synchronized (session) { 

slist=(searchData)session.getAttribute("searchList"); 

} 

if(ll_pos.equals("-1")){ 

//===表示不是由“下一页”过来要从头开始查数据========== 

if(slist!=null){ 

synchronized (session) { 

session.removeAttribute("searchList"); 

} 

} 

slist=new searchData(); 

//=============从设置查询条件页面取得查询条件的参数=================== 

zlbm=request.getParameter("zlbm"); 

dlbm=request.getParameter("dlbm"); 

clbm=request.getParameter("clbm"); 

zyyx=request.getParameter("zyyx"); 

ypm=request.getParameter("ypm"); 

//------------------------------------------------------ 

//=================将查询条件参数通过Vector存到session中========== 

slist.setZlbm (zlbm); 

slist.setDlbm (dlbm); 

slist.setClbm (clbm); 

slist.setZyyx (zyyx); 

slist.setYpm (ypm); 

synchronized (session) { 

session.setAttribute ("searchList",slist); 

} 

//--------------------------------------------------------- 

} 

//-------------------------------------------------------- 

else 

{ 

//============================取出查询条件参数==================== 

if(slist!=null){ 

zlbm=slist.getZlbm(); 

dlbm=slist.getDlbm(); 

clbm=slist.getClbm(); 

zyyx=slist.getZyyx(); 

ypm=slist.getYpm(); 

} 

else{ 

if(stmt!=null) stmt.close(); 

stmt.setMaxRows(0); 

connMgr.freeConnection("medicine",con); 

response.sendRedirect("/medicine/session_error.html"); 

return; 

} 

//------------------------------------------------- 

} 

String sql2="select count(*) from medicines where del_flag=0"; 

//=====================根据条件参数设置SQL语句======================= 

if(!(zlbm.trim().equals("0"))) { 

sqlstatment+=(" and ( medicines.zlbm='"+zlbm.trim()+"' ) "); 

sql2+=(" and zlbm='"+zlbm.trim()+"'"); 

} 

if(!(dlbm.trim().equals("0"))) { 

sqlstatment+=(" and ( medicines.dlbm='"+dlbm.trim()+"' )"); 

sql2+=(" and dlbm='"+dlbm.trim()+"'"); 

} 

if(!(clbm.trim().equals("0"))) { 

sqlstatment+=(" and ( medicines.clbm='"+clbm.trim()+"' ) "); 

sql2+=(" and clbm='"+clbm.trim()+"'"); 

} 

if(!(zyyx.trim().length ()==0)) { 

sqlstatment+=(" and ( medicines.zyyx like '%"+zyyx.trim()+"%' ) "); 

sql2+=(" and zyyx like '%"+zyyx.trim()+"%'"); 

} 

if(!(ypm.trim().length ()==0)) { 

sqlstatment+=(" and ( medicines.ypm like '%"+ypm.trim()+"%' ) "); 

sql2+=(" and ypm like '%"+ypm.trim()+"%'"); 

} 

sqlstatment+=" )) ORDER BY medicines.ypbm ASC "; 

//------------------------------------------------------------- 

Vector list = new Vector(); 

//================= 设置一页显示的数据条数（一次检索出的数据条数）=========== 

stmt.setMaxRows(25); 

//---------------------------------------------------------------------- 

//===================执行查询将结果放到ResultSet中================ 

ResultSet rs = stmt.executeQuery(sqlstatment); 

ResultSet rs2 = stmt.executeQuery(sql2); 

//------------------------------------------------ 

if(rs==null){ //如果没有查询结果数据 

if(stmt!=null) stmt.close(); 

stmt.setMaxRows(0); 

connMgr.freeConnection("medicine",con); 

response.sendRedirect("/medicine/no_medicine.html"); //定向到一个页面 

return; 

} 

//====================将药品信息填入数据对象并存入Vector中================ 

if(rs2.next()){ 

all_count=rs2.getLong(1); //取得总条数 

} 

if(rs2!=null)rs2.close(); 

while(rs.next()){ 

medicinelist m = new medicinelist(); 

m.setYpbm(rs.getInt("ypbm")); 

m.setZlmc(rs.getString("zlmc")); 

m.setClmc(rs.getString("clmc")); 

m.setDlmc(rs.getString("dlmc")); 

m.setYpm(rs.getString("ypm")); 

m.setZyyx(rs.getString("zyyx")); 

m.setYpzy(rs.getString("ypzy")); 

m.setClbm(clbm); 

m.setDlbm(dlbm); 

m.setZlbm(zlbm); 

list.addElement(m); 

} 

//---------------------------------------------------------- 

if(rs!=null)rs.close(); 

stmt.setMaxRows(0); 

if(stmt!=null)stmt.close(); 

connMgr.freeConnection("medicine",con); 

//========================存入session中=========================== 

synchronized (session) { 

session.setAttribute("medicinelist",list); 

} 

//----------------------------------------------- 

}catch (SQLException e){ 

connMgr.freeConnection("medicine",con); 

response.sendRedirect("/Medicine/sql_error.html"); 

return;} 

//=======================重定向到一个JSP页面========================== 

String url="/medicine/querymedicine.jsp?all_count="+all_count; 

ServletContext sc = getServletContext(); 

RequestDispatcher rd = sc.getRequestDispatcher(url); 

rd.forward(request, response); 

//------------------------------------------------------- 

} 

public void destroy() { 

// =================== 在Servlet退出时终止数据库连接,取消Statement对象 

if(connMgr!=null) connMgr.release(); 

//------------------------------------------------------------------------ 

} 

//========================处理HTTP Post 请求 ============================ 

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

doGet(request,response); 

} 

//==========================取得 Servlet 信息 ============================ 

public String getServletInfo() { 

return "medicine.querymedicine Information"; 

} 

} 

l querymedicine.jsp 

<%@ page language="java" session="true" import="java.util.*, 
Medicine.method, Medicine.medicinelist"contentType="text/html;charset=gbk" %> 

<script language="javascript"> 

function next(){ 

var ls_pos=document.form2.maxpos.value; 

document.location="/servlet/Medicine.querymedicine?pos="+ls_pos; 

} 

function detail(ypbm){ 

document.location="/servlet/Medicine.Detail?ypbm="+ypbm; 

} 

</script> 

<!--add head--> 

<div align="center"> 

<body topmargin="0" leftmargin="10" rightmargin="10” bgcolor="#FFFFFF"> 
<div align="center"> 

<center><IFRAME WIDTH=760 height=130
NORESIZE SCROLLING=no FRAMEBORDER=0 
MARGINHEIGHT=0 MARGINWIDTH=0 SRC="..medicinetitle.html"></iframe> 

</div> 

<!--finish--> 

<title>商品列表</title> 

<% 

method md = new method(); 

Vector sklist; 

synchronized (session) { 

sklist = (Vector) session.getAttribute("medicinelist"); 

} 

%>