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。

[解决办法]
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