javaBean练习
<%@   page   contentType= "text/html;charset=GB2312 "%>
<%@   include   file= "common.jsp "   %>
<%@   page   import   =   "java.io.* "%>
<%@   page   import   =   "java.util.* "%>
<%@   page   import   =   "java.sql.* "%>


<jsp:useBean   id= "DB "   scope   =   "application "   class= "ConBook "/>


<%



try{
Connection   con   =   DB.getConnection();
Statement   stmt;
ResultSet   rs;

// Class.forName( "com.mysql.jdbc.Driver ");
// DriverManager.registerDriver(new   com.mysql.jdbc.Driver());
// String   dburl   =   "jdbc:mysql://localhost:3306/BookDB ";
// String   dbUser= "dbuser ";
// String   dbPwd= "1234 ";
// con   =   java.sql.DriverManager.getConnection(dburl,dbUser,dbPwd);

stmt   =   con.createStatement();
rs   =   stmt.executeQuery( "select   id,name,title,price   from   books ");

out.println( " <table   border   =1   width=400> ");
while(rs.next()){
String   col1   =   convert(rs.getString(1));
String   col2   =   convert(rs.getString(2));
String   col3   =   convert(rs.getString(3));
float   col4   =   rs.getFloat(4);
out.println( " <tr> <td> "+col1+ " </td> <td> "+col2+ " </td> <td> "+col3+ " </td> <td> "+col4+ " </td> </tr> ");
}
out.println( " </table> ");

rs.close();
stmt.close();
con.close();
}
catch(Exception   e){
out.println(e.getMessage());
}
%>


错误：
org.apache.jasper.JasperException:   Unable   to   compile   class   for   JSP:  

An   error   occurred   at   line:   8   in   the   jsp   file:   /index.jsp
ConBook   cannot   be   resolved   to   a   type
5:   <%@   page   import   =   "java.sql.* "%>
6:  
7:  
8:   <jsp:useBean   id= "DB "   scope   =   "application "   class= "ConBook "/>
9:  
10:  
11:   <%
ConBook是个数据库连接类，已经编译好了，放在WEN-INF/classes   下。

------解决方案--------------------
加上包结构

没有包的类 是不能被有包的类访问的


我的异常网推荐解决方案：org.apache.jasper.JasperException: Unable to compile class,http://www.myexception.cn/j2ee/2308.html