jsp中的一个下拉列表实例
最近在写一个网站后台，用到了一个下拉列表，在这将代码贴出来供大家参考！（水平有限）实现的效果如下：
代码只要涉及三个文件，两个servlet文件：UserListServlet.java （负责在数据库中查询全部用户记录）和UserListByPowerServlet.java(主要根据权限来查询相关记录，当权限是“全部”时，会从此文件跳转到UserListServlet文件让其执行),还有一个jsp文件，UserList.jsp（负责显示查询的数据）
UserListServlet.java
public class UserListServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request ,response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("utf-8");
request.setCharacterEncoding("utf-8");
String pNo=request.getParameter("pNo");
if(pNo==null || pNo.equals("") || pNo.trim().equals("0")){
pNo="1";
}
oj_UserDao ud=new oj_UserDaoImpl();
int pageSize=10;
List list=ud.getUserList(Integer.parseInt(pNo), pageSize);
int totalCount=ud.totalCount();
int pageCount=totalCount%pageSize==0?totalCount/pageSize:totalCount/pageSize+1;
request.setAttribute("pNo", pNo);
request.setAttribute("totalCount", totalCount);
request.setAttribute("pageCount" ,pageCount);
request.setAttribute("userList", list);
request.setAttribute("power","全部");
request.getRequestDispatcher("tab/UserList.jsp").forward(request, response);
}
}
UserListByPowerServlet.java
public class UserListByPowerServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request,response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("utf-8");
request.setCharacterEncoding("utf-8");
String power=request.getParameter("power");
if(power.equals("全部")){
request.getRequestDispatcher("userListServlet").forward(request, response);
}
String pNo=request.getParameter("pNo");
if(pNo==null || pNo.equals("") || pNo.trim().equals("0")){
pNo="1";
}
oj_UserDao ud=new oj_UserDaoImpl();
int pageSize=10;
List list=ud.getUserList2(power,Integer.parseInt(pNo), pageSize);
int totalCount=ud.totalCount2(power);
int pageCount=totalCount%pageSize==0?totalCount/pageSize:totalCount/pageSize+1;
request.setAttribute("pNo", pNo);
request.setAttribute("totalCount", totalCount);
request.setAttribute("pageCount" ,pageCount);
request.setAttribute("userList", list);
request.setAttribute("power", power);
request.getRequestDispatcher("tab/UserList.jsp").forward(request, response);
}
}
public class UserListByPowerServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request,response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("utf-8");
request.setCharacterEncoding("utf-8");
String power=request.getParameter("power");
if(power.equals("全部")){
request.getRequestDispatcher("userListServlet").forward(request, response);
}
String pNo=request.getParameter("pNo");
if(pNo==null || pNo.equals("") || pNo.trim().equals("0")){
pNo="1";
}
oj_UserDao ud=new oj_UserDaoImpl();
int pageSize=10;
List list=ud.getUserList2(power,Integer.parseInt(pNo), pageSize);
int totalCount=ud.totalCount2(power);
int pageCount=totalCount%pageSize==0?totalCount/pageSize:totalCount/pageSize+1;
request.setAttribute("pNo", pNo);
request.setAttribute("totalCount", totalCount);
request.setAttribute("pageCount" ,pageCount);
request.setAttribute("userList", list);
request.setAttribute("power", power);
request.getRequestDispatcher("tab/UserList.jsp").forward(request, response);
}
}
UserList.jsp(没必要看所有的，只看与下拉列表相关的mygetmoredata（）js函数，和select下拉列表)
<%@ page language="java" import="java.util.*,model.oj_user" pageEncoding="utf-8"%>
<%
List userList=(List)request.getAttribute("userList");
int totalCount=Integer.parseInt(request.getAttribute("totalCount").toString());
String s=request.getAttribute("pageCount").toString();
int pageCount=Integer.parseInt(s);
String power=request.getAttribute("power").toString();
int pNo=Integer.parseInt(request.getAttribute("pNo").toString());
%>
全选 
添加 
删除
序号
用户名
用户角色
密码
总提交数
通过数
基本操作
<%
if(userList!=null){
for(int i=0;i
οnclick="checkItem(this, 'mmAll')">
<%=i+1%>
<%= user.getName()%>
<%=user.getPower() %>
<%=user.getPassword() %>
<%=user.getTotal() %>
<%=user.getAccept() %>
删除 | 编辑 | 查看
<%
}}
%>
共有 <%=totalCount %> 条记录，当前第 <%=pNo %> 页，共 <%=pageCount %> 页
他们之间的关系大致为，当第一次从别的网页要跳到userList.jsp时，首先跳到UserListServlet.jsp查询全部的数据，当在jsp页面按权限查找时，跳到UserListByPowerServlet之后，查询数据，再将数据返回到jsp页面进行显示，当在UserlistByPower遇到的权限是“全部”时，此servlet不进行查询，跳到userlistservlet后，再查询！！！