源代码如下:
GetUserInfo.java代码:
package testbeans;
import java.sql.*;
import java.util.*;
public class GetUserInfo {
public Connection con;
public GetUserInfo(){
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
String ulr="jdbc:odbc:forum";
String user="";
String pwd="";
con=DriverManager.getConnection(ulr,user,pwd); } catch(Exception e)
{e.printStackTrace();
}
}
public Vector getInfo()
{ Vector result=new Vector();
String sql="select * from topic";
try{
Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery(sql);
while(rs.next()){
String author=rs.getString("author");
result.addElement(author);
String subject=rs.getString("subject");
result.addElement(subject);
String email=rs.getString("email");
result.addElement(email);
String content=rs.getString("content");
result.addElement(content);
}
rs.close();
stmt.close();
con.close();
}catch(Exception e){}
return result;
}
} index.jsp代码:
<%@page contentType="text/html;charset=gb2312"import="java.util.*" %>
<jsp:useBean id="info" scope="page" class="testbeans.GetUserInfo">
</jsp:useBean>
<%
Vector vec=info.getInfo();
int count=vec.size();
out.print(count);
String str=new String("");
for(int i=0;i<count;i++)
{
str+=vec.elementAt(i).toString();
}
if(count!=0)
{out.print(str);}
%>
编译时报错:
org.apache.jasper.JasperException: Exception in JSP: /index.jsp:11 8: String str=new String("");
9: for(int i=0;i<count;i++)
10: {
11: str+=vec.elementAt(i).toString();
12: }
13: if(count!=0)
14: {out.print(str);} 如果不用循环,只写str=vec.elementAt(1).toString()可以得出正确结束,但是用循环却不行,请高手帮我纠正一下,谢谢了!
GetUserInfo.java代码:
package testbeans;
import java.sql.*;
import java.util.*;
public class GetUserInfo {
public Connection con;
public GetUserInfo(){
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
String ulr="jdbc:odbc:forum";
String user="";
String pwd="";
con=DriverManager.getConnection(ulr,user,pwd); } catch(Exception e)
{e.printStackTrace();
}
}
public Vector getInfo()
{ Vector result=new Vector();
String sql="select * from topic";
try{
Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery(sql);
while(rs.next()){
String author=rs.getString("author");
result.addElement(author);
String subject=rs.getString("subject");
result.addElement(subject);
String email=rs.getString("email");
result.addElement(email);
String content=rs.getString("content");
result.addElement(content);
}
rs.close();
stmt.close();
con.close();
}catch(Exception e){}
return result;
}
} index.jsp代码:
<%@page contentType="text/html;charset=gb2312"import="java.util.*" %>
<jsp:useBean id="info" scope="page" class="testbeans.GetUserInfo">
</jsp:useBean>
<%
Vector vec=info.getInfo();
int count=vec.size();
out.print(count);
String str=new String("");
for(int i=0;i<count;i++)
{
str+=vec.elementAt(i).toString();
}
if(count!=0)
{out.print(str);}
%>
编译时报错:
org.apache.jasper.JasperException: Exception in JSP: /index.jsp:11 8: String str=new String("");
9: for(int i=0;i<count;i++)
10: {
11: str+=vec.elementAt(i).toString();
12: }
13: if(count!=0)
14: {out.print(str);} 如果不用循环,只写str=vec.elementAt(1).toString()可以得出正确结束,但是用循环却不行,请高手帮我纠正一下,谢谢了!
解决方案 »
- java如何实现网页程序自动登录
- jasper excel导出问题java.lang.NoSuchMethodError: org.apache.poi.hssf.usermodel.HSSFS
- struts+hibernate的简单问题
- hibernate如何执行sql语句的insert动作?
- 菜鸟问题,希望能得到你的热心帮助
- 我想将index.jsp通过其他的jsp或javabean文件执行后生成index.html文件,注意并不是表单提交后生成html文件。
- 请教高手们
- 文件上传,本地POST->JSP.SMARTUPLOAD->远程服务器?如何实现?
- 如何得到submit那个按钮的name???
- fullcalendar在周和日模式下 点击日程事件没有但应,并且日程的缩放也失灵,求解释
- 请高手帮忙看一下导航条,急!
- 关于servlet中调用数据库连接的问题,对数据库的操作老是无效,求高手指点
String temp=vec.elementAt(i);
if(temp!=null)
{
str+=temp.toString;
}
试一下,关键是把错误定位然后就好解决。
另外数据库这些字段都什么类型,是不是存有GBK,ISO之类编码的字符串
8: String str="";
9: for(int i=0;i<count;i++)
10: {
11: str+=(String)vec.get(i);
12: }
13: if(count!=0)
14: {out.print(str);}