ResultSet本来就是一个记录集,执行后存储你的执行结果(就是所有的username)在里面,你只需要在页面显示就ok了你是不是用jsp来写哦?!@
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.....
}
String zhiwei=request.getParameter("zhiwei");
String username;
int count=0;
try
{
Connection con=pcon.getConnection();
Statement stmt=con.createStatement();
String psql="select count(username) from register where department='"+department+"' and zhiwei='"+zhiwei+"'";
ResultSet res=stmt.executeQuery(psql);
while(res.next())
{
username=res.getString("username");
count++;
}
}
catch(Exception e)
{
}
save.getUsername();
save.getCount();
%>
javaBean package gold.city;
import java.util.*;
import java.io.*;public class choosePerson
{
String []username;
String user;
int count=0;
public choosePerson()
{
}
public void setCount()
{
count++;
}
public int getCount()
{
return count;
}
public void setUsername(String user)
{
this.user=user;
username[count]=user;
}
public String[] getUsername()
{
return username;
}}
各位请帮忙修改一下
<%@ page import="java.io.*"%>
<%@ page import="java.sql.*"%>
<%@ page import="java.util.*"%>
<HTML>
<BODY bgcolor="#ccffcc" text="#336633" link="#0066cc" vlink="#009999" alink="#ff9900">
<jsp:useBean id="pcon" scope="page" class="gold.city.connectionDb"/>
<jsp:useBean id="save" scope="page" class="gold.city.choosePerson"/>
<%
String department=request.getParameter("department");
String zhiwei=request.getParameter("zhiwei");
String user="dzs";
int count=0;
try
{
Connection con=pcon.getConnection();
Statement stmt=con.createStatement();
String psql="select username from register where department='"+department+"' and zhiwei='"+zhiwei+"'";
ResultSet res=stmt.executeQuery(psql);
while(res.next())
{
user=res.getString("username");
save.setUsername(user);
out.println(user);
count++;
out.println(count);
out.println(user);
}
out.println(count);
}
catch(Exception e)
{
}
save.setCount(count++);
String username[]=save.getUsername();
for(int j=0;j<=count;j++)
{
out.println(username[j]);
}
%>
<FORM METHOD="POST" action="choosePerson.jsp">
<P>部门:<SELECT size="1" name="department">
<OPTION value="jiaowuchu">教务处</OPTION>
<OPTION value="xinxigongcheng">信息工程学院</OPTION>
<OPTION value="xinxiguanli">信息管理学院</OPTION>
<OPTION value="tongxingongcheng" selected>通信工程</OPTION>
</SELECT><BR>
职位:<SELECT size="1" name="zhiwei">
<OPTION value="chuzhang">处长</OPTION>
<OPTION value="fuzhuzhang">副处长</OPTION>
<OPTION value="jiaoshi" selected>教师</OPTION>
</SELECT> <INPUT type="submit" name="submit" value="sure"><BR>
<SELECT size="2" name="chooseperson">
<OPTION><%=department%></OPTION>
<OPTION></OPTION>
<OPTION>11</OPTION>
<OPTION>12</OPTION>
<OPTION selected>44</OPTION>
</SELECT></FORM>
</BODY>
</HTML>
package gold.city;
import java.util.*;
import java.io.*;public class choosePerson
{
String []username;
String user;
int counter;
int m=0;
public choosePerson()
{
}
public void setCount(int counter)
{
this.counter=counter;
}
public int getCount()
{
return counter;
}
public void setUsername(String user)
{
this.user=user;
m++;
username[m]=user;
}
public String[] getUsername()
{
return username;
}
}
我编译后!
java.lang.NullPointerException
at theme.personinfo.choosePerson_jsp_48._jspService(choosePerson.jsp :43)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:139)
谢谢,各位高手指点!
当我加入save.setUsername(user)
and save.setcout(count);
是不能得到答案
这样看看:
int aa
aa="人数"
String username[]=new String[aa];(通过服务器中转)
JDOM RUI (15:34:27):
再用username.length检查以下你的数组到底容量多大,就知道是不是数组越界了。