复仇之矛教学s7:jsp出现下问题怎么解决

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

Generated servlet error:
D:\Tomcat 5.0\work\Catalina\localhost\_\org\apache\jsp\news\oa\main\index_jsp.java:8: package oa.main does not exist
import oa.main.DealString;
^

An error occurred at line: 3 in the jsp file: /news/oa/main/index.jsp
Generated servlet error:
D:\Tomcat 5.0\work\Catalina\localhost\_\org\apache\jsp\news\oa\main\index_jsp.java:49: package oa.bean does not exist
oa.bean.MainBean myBean = null;
^

An error occurred at line: 3 in the jsp file: /news/oa/main/index.jsp
Generated servlet error:
D:\Tomcat 5.0\work\Catalina\localhost\_\org\apache\jsp\news\oa\main\index_jsp.java:51: package oa.bean does not exist
myBean = new oa.bean.MainBean();
^

An error occurred at line: 3 in the jsp file: /news/oa/main/index.jsp
Generated servlet error:
D:\Tomcat 5.0\work\Catalina\localhost\_\org\apache\jsp\news\oa\main\index_jsp.java:52: cannot resolve symbol
symbol : class DealString
location: class org.apache.jsp.news.oa.main.index_jsp
DealString ds = new DealString();
^

An error occurred at line: 3 in the jsp file: /news/oa/main/index.jsp
Generated servlet error:
D:\Tomcat 5.0\work\Catalina\localhost\_\org\apache\jsp\news\oa\main\index_jsp.java:52: cannot resolve symbol
symbol : class DealString
location: class org.apache.jsp.news.oa.main.index_jsp
DealString ds = new DealString();
^
5 errors

org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:332)
org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:412)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:472)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:451)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:439)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:511)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:295)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
谢谢， 我查过了
你说的那，存在了呢