访问计数器:(JSP+JavaBean)
icounter.jsp
其代码如下:
%@page contentType="text/html;charset=gb2312"%>
<%@page import="java.io.*"%>
<%@page import="java.util.*"%>
<jsp:useBean id="icounter" scope="request" class="mypack.icounter"/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>图形计数器</title>
</head>
<body>
<%
icounter.path="C:\Program Files\Apache Software Foundation\Tomcat 5.5\webapps\myapp\icounter.txt";
char[]counts=icounter.doCount();
%>
你是本网站的第
<%
for(int i=0;i<counts.length;i++)
{
out.print("<img src=\""+counts[i]+".gif\"width=\"38\"height=\"55\">");
}
%>
位访客
</body>
</html>%@page contentType="text/html;charset=gb2312"%>
<%@page import="java.io.*"%>
<%@page import="java.util.*"%>
<jsp:useBean id="icounter" scope="request" class="mypack.icounter"/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>图形计数器</title>
</head>
<body>
<%
icounter.path="C:\Program Files\Apache Software Foundation\Tomcat 5.5\webapps\myapp\icounter.txt";
char[]counts=icounter.doCount();
%>
你是本网站的第
<%
for(int i=0;i<counts.length;i++)
{
out.print("<img src=\""+counts[i]+".gif\"width=\"38\"height=\"55\">");
}
%>
位访客
</body>
</html>icounter.java 代码:::package mypack;
import java.io.*;
public class icounter extends Object
{
public String path="";
public char[] counts;
public char[] doCount()throws FileNotFoundException
{
BufferedReader file;
String countFile=path;
file=new BufferedReader(new FileReader(countFile));
String readStr="";
int writeStr=1;
try
{
readStr=file.readLine();
}
catch(IOException e)
{
System.out.println("读取数据错误");
}
// file.close();
if(readStr=="")
readStr="没有任何记录";
else
writeStr=Integer.parseInt(readStr)+1;
try
{
PrintWriter pw=new PrintWriter(new FileOutputStream(countFile));
pw.println(writeStr);
pw.close();
}
catch(IOException e)
{
System.out.println(e.getMessage());
}
counts=readStr.toCharArray();
return counts;
}
}
运行后:出现这样的错误
type 异 常 报 告信 息 描 述 服务器遇到内部错误,无法满足这个访问请求异 常 org.apache.jasper.JasperException: /icounter.jsp(4,0) useBean类的属性 mypack.icounter的数值无效。 org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:512)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
起 因 org.apache.jasper.JasperException: /icounter.jsp(4,0) useBean类的属性 mypack.icounter的数值无效。 org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:39)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:405)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:146)
org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1174)
org.apache.jasper.compiler.Node$UseBean.accept(Node.java:1116)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2213)
org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2219)
org.apache.jasper.compiler.Node$Root.accept(Node.java:456)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
org.apache.jasper.compiler.Generator.generate(Generator.java:3320)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:198)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:295)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:276)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:264)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:563)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:305)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
注 意 完整的起因在Apache Tomcat/5.5.20里。
请问高手,是什么原因???急,谢谢!!!
icounter.jsp
其代码如下:
%@page contentType="text/html;charset=gb2312"%>
<%@page import="java.io.*"%>
<%@page import="java.util.*"%>
<jsp:useBean id="icounter" scope="request" class="mypack.icounter"/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>图形计数器</title>
</head>
<body>
<%
icounter.path="C:\Program Files\Apache Software Foundation\Tomcat 5.5\webapps\myapp\icounter.txt";
char[]counts=icounter.doCount();
%>
你是本网站的第
<%
for(int i=0;i<counts.length;i++)
{
out.print("<img src=\""+counts[i]+".gif\"width=\"38\"height=\"55\">");
}
%>
位访客
</body>
</html>%@page contentType="text/html;charset=gb2312"%>
<%@page import="java.io.*"%>
<%@page import="java.util.*"%>
<jsp:useBean id="icounter" scope="request" class="mypack.icounter"/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>图形计数器</title>
</head>
<body>
<%
icounter.path="C:\Program Files\Apache Software Foundation\Tomcat 5.5\webapps\myapp\icounter.txt";
char[]counts=icounter.doCount();
%>
你是本网站的第
<%
for(int i=0;i<counts.length;i++)
{
out.print("<img src=\""+counts[i]+".gif\"width=\"38\"height=\"55\">");
}
%>
位访客
</body>
</html>icounter.java 代码:::package mypack;
import java.io.*;
public class icounter extends Object
{
public String path="";
public char[] counts;
public char[] doCount()throws FileNotFoundException
{
BufferedReader file;
String countFile=path;
file=new BufferedReader(new FileReader(countFile));
String readStr="";
int writeStr=1;
try
{
readStr=file.readLine();
}
catch(IOException e)
{
System.out.println("读取数据错误");
}
// file.close();
if(readStr=="")
readStr="没有任何记录";
else
writeStr=Integer.parseInt(readStr)+1;
try
{
PrintWriter pw=new PrintWriter(new FileOutputStream(countFile));
pw.println(writeStr);
pw.close();
}
catch(IOException e)
{
System.out.println(e.getMessage());
}
counts=readStr.toCharArray();
return counts;
}
}
运行后:出现这样的错误
type 异 常 报 告信 息 描 述 服务器遇到内部错误,无法满足这个访问请求异 常 org.apache.jasper.JasperException: /icounter.jsp(4,0) useBean类的属性 mypack.icounter的数值无效。 org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:512)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
起 因 org.apache.jasper.JasperException: /icounter.jsp(4,0) useBean类的属性 mypack.icounter的数值无效。 org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:39)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:405)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:146)
org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1174)
org.apache.jasper.compiler.Node$UseBean.accept(Node.java:1116)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2213)
org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2219)
org.apache.jasper.compiler.Node$Root.accept(Node.java:456)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
org.apache.jasper.compiler.Generator.generate(Generator.java:3320)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:198)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:295)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:276)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:264)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:563)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:305)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
注 意 完整的起因在Apache Tomcat/5.5.20里。
请问高手,是什么原因???急,谢谢!!!
意思是找不到icounter这个类请参考我们教程中使用useBean的例子:http://test.family168.com/tutorial/jsp/html/jsp-ch-05.html