Question

我还在学习开发webapps。我遇到了这个教程。

EmpBean.java

package form;
import java.sql.*;
import java.util.*;
public class EmpBean {

public List dataList(){
ArrayList list=new ArrayList();
try{
     Class.forName("com.mysql.jdbc.Driver");
           Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root");
           Statement st=con.createStatement();
           ResultSet rs=st.executeQuery("select * from employee");
           while(rs.next()){
               list.add(rs.getString("name"));
               list.add(rs.getString("address"));
               list.add(rs.getString("contactNo"));
               list.add(rs.getString("email"));

}
}
catch(Exception e){}
return list;

}
}

BeanInServlet.java

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class BeanInServlet extends HttpServlet{
    protected void doGet(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException{
        form.EmpBean p = new form.EmpBean();
        List list=p.dataList();

        req.setAttribute("data", list);
        RequestDispatcher rd = req.getRequestDispatcher("/jsp/beandata.jsp");
        rd.forward(req, res);
    }
}

beandata.jsp

<%@page language="java" import="java.util.*" %>
<html>
<body> 
<table border="1" width="303">
<tr>
<td width="119"><b>Name</b></td>
<td width="168"><b>Address</b></td>
<td width="119"><b>Contact no</b></td>
<td width="168"><b>Email</b></td>
</tr>
<%Iterator itr;%>
<% List data= (List)request.getAttribute("data");
for (itr=data.iterator(); itr.hasNext(); ){
%>
<tr>
<td width="119"><%=itr.next()%></td>
<td width="168"><%=itr.next()%></td>
<td width="168"><%=itr.next()%></td>
<td width="168"><%=itr.next()%></td>
</tr>
<%}%>
</table>
</body>
</html>

我尝试使用netbeans并且它可以工作..但是我想知道JSTL是否可以用来呈现数据（View）。

Answer 1

c：foreach就是你要找的东西。虽然这当然假设您的列表是4的倍数。这是从内存中完成的，所以我不保证不会出现语法错误。

<table>
<c:foreach var="item" varStatus="status" items="${requestScope.data}">
 <c:choose>
  <c:when test="${status.index % 4 == 0}">
   <tr>
   <td width="119"><c:out value="${item}" /></td>
  </c:when>
  <c:otherwise>
   <td width="168"><c:out value="${item}" /></td>
  </c:otherwise>   
 </c:choose>
 <c:if test="${status.index % 4 == 3}">
  </tr>
 </c:if>
</c:foreach>
</table>

使用bean和servlet显示数据

1 个答案: