我碰到这样一个问题,找不到Bean 对象,哪位能帮忙指点下,谢谢!jsp,java src与class文件在目录D:\myJSP\jsp\count下面
另外还有一文本文件lyfcount.txt也放在D:\myJSP\jsp\count下面
原文件如下:
//test.jsp文件
<%@ page contentType="text/html;charset=gb2312"%>
<%@ page language="java" import="count.*" %>
<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<META NAME="GENERATOR" CONTENT="Oracle JDeveloper">
<TITLE>
计数器演示程序
</TITLE>
</HEAD>
<BODY>
<!--创建并调用bean(counter)-->
<jsp:useBean id="counter" class="count.counter" scope="request">
</jsp:useBean>
<%
//调用counter对象的ReadFile方法来读取文件lyfcount.txt中的计数
String cont=counter.ReadFile("/lyfcount.txt");
//调用counter对象的ReadFile方法来将计数器加一后写入到文件lyfcount.txt中
counter.WriteFile("/lyfcount.txt",cont);%>
您是第<font color="red"><%=cont%></font>位访问者
</BODY>
</HTML>
java src 如下:
//counter.java 读写文件的一个bean
package count;
import java.io.*;
public class counter extends Object {
private String currentRecord = null;//保存文本的变量
private BufferedReader file; //BufferedReader对象,用于读取文件数据
private String path;//文件完整路径名
public counter() {
}
//ReadFile方法用来读取文件filePath中的数据,并返回这个数据
public String ReadFile(String filePath) throws FileNotFoundException
{
path = filePath;
//创建新的BufferedReader对象
file = new BufferedReader(new FileReader(path));
String returnStr =null;
try
{
//读取一行数据并保存到currentRecord变量中
currentRecord = file.readLine();
}
catch (IOException e)
{//错误处理
System.out.println("读取数据错误.");
}
if (currentRecord == null)
//如果文件为空
returnStr = "没有任何记录";
else
{//文件不为空
returnStr =currentRecord;
}
//返回读取文件的数据
return returnStr;
}
//ReadFile方法用来将数据counter+1后写入到文本文件filePath中
//以实现计数增长的功能
public void WriteFile(String filePath,String counter) throws FileNotFoundException
{
path = filePath;
//将counter转换为int类型并加一
int Writestr = Integer.parseInt(counter)+1;
try {
//创建PrintWriter对象,用于写入数据到文件中
PrintWriter pw = new PrintWriter(new FileOutputStream(filePath));
//用文本格式打印整数Writestr
pw.println(Writestr);
//清除PrintWriter对象
pw.close();
} catch(IOException e) {
//错误处理
System.out.println("写入文件错误"+e.getMessage());
}
}
}
在IE中运行test.jsp文件错误如下:
HTTP Status 500 -
--------------------------------------------------------------------------------
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: 13 in the jsp file: /jsp/count/test.jsp
Generated servlet error:
[javac] Compiling 1 source file
C:\Tomcat4\work\Standalone\localhost\myJSP\jsp\count\test_jsp.java:7: package count does not exist
import count.*;
^
C:\Tomcat4\work\Standalone\localhost\myJSP\jsp\count\test_jsp.java:54: cannot resolve symbol
symbol : class counter
location: package count
count.counter counter = null;
^
An error occurred at line: 13 in the jsp file: /jsp/count/test.jsp
Generated servlet error:
C:\Tomcat4\work\Standalone\localhost\myJSP\jsp\count\test_jsp.java:56: cannot resolve symbol
symbol : class counter
location: package count
counter = (count.counter) pageContext.getAttribute("counter", PageContext.REQUEST_SCOPE);
^
An error occurred at line: 13 in the jsp file: /jsp/count/test.jsp
Generated servlet error:
C:\Tomcat4\work\Standalone\localhost\myJSP\jsp\count\test_jsp.java:59: cannot resolve symbol
symbol : class counter
location: package count
counter = (count.counter) java.beans.Beans.instantiate(this.getClass().getClassLoader(), "count.counter");
^
4 errors