D:\Tomcat 4.1\work\Standalone\localhost\jsp\yonghuguanli\reg2_jsp.java:57: cannot resolve symbol
symbol : class opendb
location: class opendb.opendb
opendb.opendb db = null;
symbol : class opendb
location: class opendb.opendb
opendb.opendb db = null;
<jsp:useBean id="db" scope="page" class="opendb.opendb" />
调用包opendb中的opendb类,有什么错误吗?
package opendb;
//引入java.sql.*
import java.sql.*;
//包opendb中的类opendb
public class opendb
{
//定义数据库连接字符串,jdbc.odbc桥
String sDBDriver="sun.jdbc.odbc.JdbcOdbcDriver";
String sConnStr="jdbc:odbc:JSP";
Connection conn=null;
ResultSet rs=null;
//定义打开数据库连接的函数
public opendb()
{
try{
Class.forName("sDBDriver");
}
//处理异常
catch (java.lang.ClassNotFoundException e){
System.err.println("opendb():"+e.getMessage());
}
}
//定义执行SQL语句的函数
public ResultSet executeQuery(String sql)
{
rs=null;
try
{
conn=DriverManager.getConnection(sConnStr,"sa","");
Statement stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
}
//异常处理
catch (SQLException ex)
{
System.err.println("aq.executeQuery:"+ex.getMessage());
}
return rs;
}
}以上就是opendb.java的完整源码
<jsp:useBean id="db" scope="page" class="opendb.opendb" />
<%
//判断所选的用户ID是否与现有ID重名
String uid=request.getParameter("uid");
//生成查询的sql命令
String sql="select * from custom where uid='"+uid+"'";
//rs为返回结果的ResultSet对象
ResultSet rs=db.executeQuery(sql);就是这样调用的
检查你的路径是不是对了
是在classes\opendb下吗?
<jsp:useBean id="db" scope="page" class="opendb.opendb" />
你写重复啦
因为你已经import这个包下的所有类啦
所以在你指定class的时候就不用写这个包名啦
<%@ page import="opendb.*"%>
<jsp:useBean id="db" scope="page" class="opendb" />或
<%@ page contentType="text/html;charset=GB2312"%>
<jsp:useBean id="db" scope="page" class="opendb.opendb" />
<%@ page import="opendb.*"%>
<jsp:useBean id="db" scope="page" class="opendb" />,有以下错误:
type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException: opendb
at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:498)
at org.apache.jsp.reg2_jsp._jspService(reg2_jsp.java:270)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:92)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:809)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:162)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:240)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:187)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:809)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:200)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:209)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)