本文目录一览：
- 1、连接数据库进行查询，怎样把查询到的结果在jsp中显示，在servlet使用Dao中的方法是什么？
- 2、jsp查询数据库代码
- 3、jsp页面调用dao方法问题
- 4、JSP连接数据库的代码
- 5、写了一个Dao，连接数据库进行查询，怎样把查询到的结果在jsp中显示，在servlet在使用Dao中的方法，
连接数据库进行查询，怎样把查询到的结果在jsp中显示，在servlet使用Dao中的方法是什么？
servlet配置到你的wed.xml中。
从数据库中获取到的数据放进响应中然后通过%=request.getAttribute("bookId1") %获取对应的值当然仅仅有servlet和jsp页面是不够的还须要的是servlet配置到你的wed.xml中。这样servlet才干够使用。
具体代码如下：
package bookConnUtil;
import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class selectBook extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
jsp查询数据库代码
这种方法并不是很常用,只是页面的相关操作，代码太多,所以中间省略了部分%
Object userUID=session.getAttribute("USERID");
String uid="";
if(userUID!=null)
{
uid=(String)userUID;
}
else
{ response.sendRedirect("../Public/loseSession.jsp");}
try
{
String today=DateUtils.getInstance().getToday();
String userIP=request.getRemoteAddr();
String sql="";
String getPage=request.getParameter("toPage");
sql=cu.exchange(request.getParameter("sql")); if (sql==null||sql.equals("")){
String getDepId="";
String getPoliticalPosition="";
String getTechnicalPosition="";
String getPoliticalLevel="";
String getTechnicalLevel="";
String getDegreeCode="";
String getGrade="";
String getLongevity="";String getAllowance="";
long depId=0;
long degreeCode=0;
long politicalPosition=0;
long technicalPosition=0;
long politicalLevel=0;
long technicalLevel=0;
long grade=0;
long longevity=0;
long allowance=0;
String[] postID=null;
String post="";
String userID="";
String userName="";
String address="";
getDepId=request.getParameter("depId");
depId=Long.parseLong(getDepId.trim());getDegreeCode=request.getParameter("degreeCode");
if (getDegreeCode!=null) {
degreeCode=Long.parseLong(getDegreeCode.trim());
}
getPoliticalPosition=request.getParameter("politicalPosition");
if (getPoliticalPosition!=null) {
politicalPosition=Long.parseLong(getPoliticalPosition.trim());
}
post=request.getParameter("post");
if(post!=nullpost.trim().equals("1"))
postID=request.getParameterValues("dyourlocation");
getTechnicalPosition=request.getParameter("technicalPosition");if (getTechnicalPosition!=null) {
technicalPosition=Long.parseLong(getTechnicalPosition.trim());
}
getPoliticalLevel=request.getParameter("politicalLevel");if (getPoliticalLevel!=null) {politicalLevel=Long.parseLong(getPoliticalLevel.trim());
}getTechnicalLevel=request.getParameter("technicalLevel");if (getTechnicalLevel!=null) {
technicalLevel=Long.parseLong(getTechnicalLevel.trim());
}getGrade=request.getParameter("grade");if (getGrade!=null) {
grade=Long.parseLong(getGrade.trim());
}getLongevity=request.getParameter("longevity");if (getLongevity!=null) {
longevity=Long.parseLong(getLongevity.trim());
}getAllowance=request.getParameter("allowance");
if (getAllowance!=null) {
allowance=Long.parseLong(getAllowance.trim());
}
userID=ParamUtils.getParameter(request,"userID");//用户代码
userName=ParamUtils.getParameter(request,"userName");
//用户名称
address=ParamUtils.getParameter(request,"address");
//得到要转入的页面sql="select org_user.* from org_user,org_detail where org_user.user_id=org_detail.user_id";
if (depId!=0)
{
sql=sql+" and org_user.department_id="+depId+"";
}if (userID!=nulluserID!=""){
sql=sql+" and org_user.user_id='"+userID+"'";
}
if (userName!=nulluserName!="")
{
sql=sql+" and org_user.name like '%"+userName+"%'";
}if (address!=nulladdress!="")
{
sql=sql+" and org_user.address like '%"+address+"%'";
}
if(post!=null!post.trim().equals("0"))
{
sql=sql+" and org_detail.post in (";
for(int i=0;ipostID.length;i++)
{
sql=sql+postID[i];
if(i!=(postID.length-1))
sql=sql+",";
}
sql=sql+")";
}
if (degreeCode!=0)
{
sql=sql+" and org_detail.degree="+degreeCode+"";
}
if (politicalPosition!=0)
{
sql=sql+" and org_detail.politicalPosition="+politicalPosition+"";
}
if (technicalPosition!=0)
{
sql=sql+" and org_detail.technicalPosition="+technicalPosition+"";
}
if (technicalPosition!=0)
{
sql=sql+" and org_detail.politicalLevel="+politicalLevel+"";
}
if (grade!=0)
{
sql=sql+" and org_detail.grade="+grade+"";
}
if (longevity!=0)
{
sql=sql+" and org_detail.longevity="+longevity+"";
}
if(getAllowance!=null)
{
if (allowance==0||allowance==1)
{
sql=sql+" and org_detail.allowance="+allowance+"";
}
}
}
User[] userList =null;
userList=ur.complexSearch(sql);
log.addLog(1,1,1,uid,userIP,uid+"于("+today+")查询员工");int cnt=userList.length;//总记录数
int pageSize=10;//每页显示记录数
int curPage=1;//当前页
int cntPage;//总页数
int m=1; if (cnt0)
{
if (cnt%pageSize==0)
cntPage=cnt/pageSize;
else
cntPage=cnt/pageSize+1;
}
else
cntPage=0; if (getPage==null)
{
getPage="1";
curPage=1;
}
else
curPage=Integer.parseInt(getPage.trim());
%form name="thisform" action="userSearchDel.jsp" method="post"
table bgColor="#FFFFFF" border="1" borderColorDark="#ffffff" borderColorLight="#c0c0c0" cellSpacing="0" width="95%" cellpadding="4"
tr height="25" align="center" bgcolor="#959595"
td /td
tdfont color="#FFFFFF"姓名/font/td
tdfont color="#FFFFFF"性别/font/td
td font color="#FFFFFF"所在部门/font/td
td font color="#FFFFFF"办公地址/font/td
tdfont color="#FFFFFF"联系电话/font/td
/tr
%
int u=1;
for(int i=0;icnt;i++)
{
//显示记录的起始位置
int j=(curPage-1)*pageSize;
//显示记录的末位置
int k=curPage*pageSize;
//只显示page_size条数据
if(mjm=k)
{
String userId=userList[i].getUserID();
String gender=userList[i].getGender();
String name=userList[i].getName();
String tel=userList[i].getTel();
String useAddress=userList[i].getAddress();
long dep_id=userList[i].getDepID();
String dname=dep.getName(userList[i].getDepID());
if(tel==null||tel.equals("null"))
tel="";
if(useAddress==null||useAddress.equals("null"))
useAddress="";
//判断没一行该输出的颜色
if((u%2)==0)
{
out.println("tr bgcolor=#D7D7D7 onMouseOver=this.style.backgroundColor='#fcd4d7'; onMouseOut=if(selectedItem!=this.id){this.style.backgroundColor='#D7D7D7';}");
}
else
{
out.println("tr onMouseOver=this.style.backgroundColor='#fcd4d7'; onMouseOut=if(selectedItem!=this.id){this.style.backgroundColor='#FFFFFF';}");
}
u++;
%
td align=centerinput type="checkbox" name="checkbox" id="CHK_+%=userId%" value="%=userId%"/td
td align=center
%
long departmentID=ur.getDepID(uid);
if(up.haveRight(uid,"USER_COMPLEXQUERY")==true)
{
%
a href="userAnalyze.jsp?userId=%=userId%dep_id=%=dep_id%toPage=%=curPage%"font color="#330099"
%
}
else if(up.haveRight(uid,"DEPARTMENT_PLATFORM")==truedep_id==departmentID)
{
%
a href="userAnalyze.jsp?userId=%=userId%dep_id=%=dep_id%toPage=%=curPage%"font color="#330099"
%
}
%
%=name%/font/a/td
%
if(gender.trim().equals("0"))
out.println("td align=center男/td");
else
out.println("td align=center女/td");
%
td align=centera href="depintro.jsp?id=%=dep_id%toPage=%=curPage%"font color="#330099"%=dname%/font/a/td
td align=center %=useAddress%/td
td align=center %=tel%/td
/tr
%
}//end if m++;
}//end for
%
input type=hidden name="sql" value="%=sql%"
input type=hidden name="page" value="%=curPage%"
/table
/form
form name=pageform action="searchAction.jsp" method="post"
table border="0" width="95%"
tr
td align="center"第%=curPage%页/共%=cntPage%页/td
td align="left"
img name="firstpage" src="../Image/btn_firstpage.gif" style="cursor:hand" onclick="pageClick(1)" %=curPage1?" ":"disabled"%
img name="prepage" src="../Image/btn_prepage.gif" style="cursor:hand" onclick="pageClick(%=curPage-1%)" %=curPage1?" ":"disabled"%
img name="nextpage" src="../Image/btn_nextpage.gif" style="cursor:hand" onclick="pageClick(%=curPage+1%)" %=curPagecntPage?" ":"disabled"%
img name="lastpage" src="../Image/btn_lastpage.gif" style="cursor:hand" onclick="pageClick(%=cntPage%)" %=curPagecntPage?" ":"disabled"%
/td
td align=left width=55%
到第input type="text" name="goPage" size="4"页
img border="0" src="../Image/icon_search.gif" style="cursor:hand" onclick="aPage()"
/td
/trtr
td colspan="3" valign="middle" width="23%" align="right"
%
if(up.haveRight(uid,"USER_MANAGE")==true)
{
%
img border="0" src="../Image/btn_delete.gif" style="cursor:hand" onclick="delUser()"
%}%
img border="0" src="../Image/btn_return.gif" style="cursor:hand" onclick="back()"
/td
input type=hidden name="sql" value="%=sql%"
input type=hidden name="toPage"
/td
/tr
/table
/form
br
br
/td
/tr
/table
/td
/tr
/table
%
}//end else
}//end try
catch(Exception e)
{
out.println(e.getMessage());
}
%
/td
/tr
/table
jsp页面调用dao方法问题
jsp没办法直接调用到DAO层的。
解释：
因为根据三层结构，jsp属于view层，之后是controler层，最好才是model层。或者是jsp为action，之后是server层，之后是dao层。不管怎么算，都没办法直接调用的。
备注：
上面的只是代码规范，但是提问非要这么干的话，也没问题，直接在java类中action方法下，调用Dao方法即可。
JSP连接数据库的代码
Class.forName("com.mysql.jdbc.Driver");
Connection conn=DriverManager.getConnection("jdbc:mysql://"+host+"/"+dbname,username,password);
Statement Stmt=conn.createStatement();
ResultSet rs=Stmt.executeQuery(sql);
这是基本的数据库操作方法
大概流程就是加载驱动类，创建连接，执行数据库操作，关闭
写了一个Dao，连接数据库进行查询，怎样把查询到的结果在jsp中显示，在servlet在使用Dao中的方法，
jsp 直接写代码好了 记得把dao倒进来就行了
%@page import="entity.*" %
%
UserDao dao =.....
ListUser users = dao.getUser.......
for( int i =0 ;iusers.size();i++){
User user = users.get(i);
%
