关于jsp连表查询dao代码的信息

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);

%