用Tomcat调试jsp程序出现如下：“cannot be resolved” ，请高手帮帮忙阿，急

[cfq19890729]

运行时出现下面的提示：An error occurred at line: 16 in the jsp file: /webchapter63/servlet/message.jsp
The method executeQuery(String) is undefined for the type DBconn
13: </tr>
14: <%
15: String sqli="SELECT * FROM mas ORDER BY 留言 id DESC";
16: ResultSet rs=con.executeQuery(sqli);
17: String color="";
18: String strpages=(String)request.getParameter("pages");
19: int pages=0;


An error occurred at line: 52 in the jsp file: /webchapter63/servlet/message.jsp
username cannot be resolved
49: %>
50: <tr bgcolor="<%=color%>">
51: <td align="center" width="86" height="22"><div align="left">留言人：</div></td>
52: <td align="center" width="158"><%=username%> </td>
53: <td height="22" colspan="2" align="left">留言主题;</td>
54: <td width="298" height="22" align="center"><%=topic%> </td>
55: </tr>


An error occurred at line: 54 in the jsp file: /webchapter63/servlet/message.jsp
topic cannot be resolved
51: <td align="center" width="86" height="22"><div align="left">留言人：</div></td>
52: <td align="center" width="158"><%=username%> </td>
53: <td height="22" colspan="2" align="left">留言主题;</td>
54: <td width="298" height="22" align="center"><%=topic%> </td>
55: </tr>
56: <tr bgcolor="<%=color%>">
57: <td width="86" height="22" align="center"><div align="left">日期：</div></td>


An error occurred at line: 58 in the jsp file: /webchapter63/servlet/message.jsp
time cannot be resolved
55: </tr>
56: <tr bgcolor="<%=color%>">
57: <td width="86" height="22" align="center"><div align="left">日期：</div></td>
58: <td width="158" height="22" align="center"><%=time%></td>
59: <td height="22" colspan="3" rowspan="3" align="left" valign="top"><%=masinfo%> </td>
60: </tr>
61: <tr bgcolor="<%=color%>">


An error occurred at line: 59 in the jsp file: /webchapter63/servlet/message.jsp
masinfo cannot be resolved
56: <tr bgcolor="<%=color%>">
57: <td width="86" height="22" align="center"><div align="left">日期：</div></td>
58: <td width="158" height="22" align="center"><%=time%></td>
59: <td height="22" colspan="3" rowspan="3" align="left" valign="top"><%=masinfo%> </td>
60: </tr>
61: <tr bgcolor="<%=color%>">
62: <td height="22" align="center"><div align="left">Email; </div></td>


An error occurred at line: 63 in the jsp file: /webchapter63/servlet/message.jsp
email cannot be resolved
60: </tr>
61: <tr bgcolor="<%=color%>">
62: <td height="22" align="center"><div align="left">Email; </div></td>
63: <td height="22" align="center"><%=email%>  </td>
64: </tr>
65: <tr bgcolor="<%=color%>">
66: <td height="22" align="center"><div align="left">处理: </div></td>


An error occurred at line: 67 in the jsp file: /webchapter63/servlet/message.jsp
id cannot be resolved
64: </tr>
65: <tr bgcolor="<%=color%>">
66: <td height="22" align="center"><div align="left">处理: </div></td>
67: <td height="22" align="center"><a href="webchapter63/servlet/delMessage?id=<%=id%>">删除留言</a></td>
68: <%
69: i++;
70: if(i==sqan)break;


An error occurred at line: 71 in the jsp file: /webchapter63/servlet/message.jsp
Syntax error, insert "Finally" to complete TryStatement
68: <%
69: i++;
70: if(i==sqan)break;
71: }
72: try{
73: con.close();
74: }


An error occurred at line: 73 in the jsp file: /webchapter63/servlet/message.jsp
con cannot be resolved
70: if(i==sqan)break;
71: }
72: try{
73: con.close();
74: }
75: catch(Exception e){
76: }


An error occurred at line: 80 in the jsp file: /webchapter63/servlet/message.jsp
pages cannot be resolved
77: %>
78: </tr>
79: <tr align="right" bgcolor="#CCCCFF">
80: <td height="22" colspan="5">第<%=(pages+1)%>/<%=countpage%>页  <a
81: href="message.jsp?pages=<%=(pages-1)%>">上一页
82: </a>  <a
83: href="message.jsp?pages=<%=(pages+1)%>">下一页</a></td>


An error occurred at line: 80 in the jsp file: /webchapter63/servlet/message.jsp
countpage cannot be resolved
77: %>
78: </tr>
79: <tr align="right" bgcolor="#CCCCFF">
80: <td height="22" colspan="5">第<%=(pages+1)%>/<%=countpage%>页  <a
81: href="message.jsp?pages=<%=(pages-1)%>">上一页
82: </a>  <a
83: href="message.jsp?pages=<%=(pages+1)%>">下一页</a></td>


An error occurred at line: 81 in the jsp file: /webchapter63/servlet/message.jsp
pages cannot be resolved
78: </tr>
79: <tr align="right" bgcolor="#CCCCFF">
80: <td height="22" colspan="5">第<%=(pages+1)%>/<%=countpage%>页  <a
81: href="message.jsp?pages=<%=(pages-1)%>">上一页
82: </a>  <a
83: href="message.jsp?pages=<%=(pages+1)%>">下一页</a></td>
84: </tr>


An error occurred at line: 83 in the jsp file: /webchapter63/servlet/message.jsp
pages cannot be resolved
80: <td height="22" colspan="5">第<%=(pages+1)%>/<%=countpage%>页  <a
81: href="message.jsp?pages=<%=(pages-1)%>">上一页
82: </a>  <a
83: href="message.jsp?pages=<%=(pages+1)%>">下一页</a></td>
84: </tr>
85: </table>
86: </body>


An error occurred at line: 181 in the generated java file
Syntax error on token "catch", Identifier expected

An error occurred at line: 183 in the generated java file
out cannot be resolved

An error occurred at line: 183 in the generated java file
_jspx_out cannot be resolved

An error occurred at line: 184 in the generated java file
out cannot be resolved

An error occurred at line: 184 in the generated java file
out cannot be resolved

An error occurred at line: 185 in the generated java file
out cannot be resolved

An error occurred at line: 186 in the generated java file
_jspx_page_context cannot be resolved

An error occurred at line: 186 in the generated java file
_jspx_page_context cannot be resolved

An error occurred at line: 188 in the generated java file
Syntax error on token "finally", { expected

An error occurred at line: 189 in the generated java file
_jspx_page_context cannot be resolved

Stacktrace:
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:92)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:423)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:316)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:294)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:281)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:566)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)

[cqlfoxufo230]

代码问题，好好检查一下，贴问题不用贴这么多，上面显示的大部分没用，问题很明显：cannot be resolved，感觉楼主是从那复制过来的代码

[wjh6018]

代码没有仔细看，个人觉得应该是哪个jsp哪个参数没有得到回值。

[ak47zhoujun]

错误信息：The method executeQuery(String) is undefined for the type DBconn
说你的DBconn没有executeQuery(String) 方法
13: </tr>
14: <%
15: String sqli="SELECT * FROM mas ORDER BY 留言 id DESC";
16: ResultSet rs=con.executeQuery(sqli);
17: String color="";
18: String strpages=(String)request.getParameter("pages");
19: int pages=0;
第16行使用con 我想这里的con 是DBcon类吧
数据库连接通常是使用Connection 创建statement或preparestatement对象 使用statement和preparestatement的execute等方法生成Resultset结果集 ，而Connection是没有executeQuery方法的
检查下你的DBCon类吧

[cfq19890729]

额 我是初学者 不怎么懂呢 是照书上写的 可是找了好久也没找到错 这是是留言板里面的一个message.jsp
现在就这个页面出现了cannot be resolved 这个错误
我是用jsp javabean Servlet共同完成的 希望有个高手能替我解决 狠谢谢 。。。 （非常急用）

[零起跑线]

An error occurred at line: 181 in the generated java file
Syntax error on token "catch", Identifier expected
一个错误发生在181行，在生成的java文件中，缺少"catch"
An error occurred at line: 188 in the generated java file
Syntax error on token "finally", { expected
一个错误发生在188行，"finally"缺少"{"

[零起跑线]

报错在181行，但是你这根本没有181行

[kerioz]

countpage cannot be resolved
问题贴具体点
你JSP里面的那个常量<%=countpage%>这玩意儿有问题
N久没写过这种内嵌的JSP代码 自己再去好好看看 贴代码的时候点击工具栏的#标识
选择代码类型 再把代码贴到

之间例

 
  你想要贴出的代码

[ak47zhoujun]

慢慢找吧 多调试调试 自己找到的 印象会更深刻，还能培养兴趣。
提取错误信息中的明显提示： 例如：The method executeQuery(String) is undefined for the type DBconn
DBconn应该是你自己的类，而executeQuery也是你自己的方法（个人的方法网上可能找不到）：
但是The method XXX is undefined for the type XXX 这样的错误一搜就知道通常情况下是类中没有定义方法导致的。试着自己去查找错误的方法 多Google

[ak47zhoujun]

The method XXX is undefined for the type XXX 方法找不到也有可能是其他原因 比如tomcat使用的不是最新编译的class文件，导致的实际类有该方法 但是还是报错 。 所以 多找找

[ljy60110]

为什么不把message.jsp贴出了呢 看错误信息看不出多少来

[li_yaya]

The method XXX is undefined for the type XXX 方法找不到也有可能是其他原因 比如tomcat使用的不是最新编译的class文件，导致的实际类有该方法 但是还是报错 。 所以 多找找