Hendrik Schreiber
help me please, I make a counter ,but it reports the errorness as follow. I use
tomcat3.1
Error: 500
Location: /website/index/file/jsp/count.jsp
Internal Servlet Error:
javax.servlet.ServletException: count.txt (系统找不到指定的文件。)
at
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:386)
at
website.index.file.jsp._0002fwebsite_0002findex_0002ffile_0002fjsp_0002fcount_0002ejspcount_jsp_2._jspService(_0002fwebsite_0002findex_0002ffile_0002fjsp_0002fcount_0002ejspcount_jsp_2.java:117)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java, Compiled
Code)
at javax.servlet.http.HttpServlet.service(HttpServlet.java, Compiled Code)
at
org.apache.jasper.runtime.JspServlet$JspServletWrapper.service(JspServlet.java,
Compiled Code)
at org.apache.jasper.runtime.JspServlet.serviceJspFile(JspServlet.java,
Compiled Code)
at org.apache.jasper.runtime.JspServlet.service(JspServlet.java, Compiled Code)
at javax.servlet.http.HttpServlet.service(HttpServlet.java, Compiled Code)
at org.apache.tomcat.core.ServletWrapper.handleRequest(ServletWrapper.java,
Compiled Code)
at org.apache.tomcat.core.ContextManager.service(ContextManager.java, Compiled
Code)
at
org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java,
Compiled Code)
at org.apache.tomcat.service.TcpConnectionThread.run(SimpleTcpEndpoint.java,
Compiled Code)
at java.lang.Thread.run(Thread.java, Compiled Code)
Root cause:
java.io.FileNotFoundException: count.txt (系统找不到指定的文件。)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.(FileInputStream.java, Compiled Code)
at java.io.FileReader.(FileReader.java:35)
at
website.index.file.jsp._0002fwebsite_0002findex_0002ffile_0002fjsp_0002fcount_0002ejspcount_jsp_2._jspService(_0002fwebsite_0002findex_0002ffile_0002fjsp_0002fcount_0002ejspcount_jsp_2.java:78)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java, Compiled
Code)
at javax.servlet.http.HttpServlet.service(HttpServlet.java, Compiled Code)
at
org.apache.jasper.runtime.JspServlet$JspServletWrapper.service(JspServlet.java,
Compiled Code)
at org.apache.jasper.runtime.JspServlet.serviceJspFile(JspServlet.java,
Compiled Code)
at org.apache.jasper.runtime.JspServlet.service(JspServlet.java, Compiled Code)
at javax.servlet.http.HttpServlet.service(HttpServlet.java, Compiled Code)
at org.apache.tomcat.core.ServletWrapper.handleRequest(ServletWrapper.java,
Compiled Code)
at org.apache.tomcat.core.ContextManager.service(ContextManager.java, Compiled
Code)
at
org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java,
Compiled Code)
at org.apache.tomcat.service.TcpConnectionThread.run(SimpleTcpEndpoint.java,
Compiled Code)
at java.lang.Thread.run(Thread.java, Compiled Code)
在 00-11-1 12:32:00 您写道：
>Hi!
>
>I currently prefer the following:
>
> * encapsulate JDBC in some kind of beans or persistence layer. Do not spread SQL
> statements all over your application. Do not embed SQL in JSP, even if some
> taglib vendors offer that as feature.
> * place your servlet independent application logic in your beans or business
> objects.
> * use a servlet or a logic JSP (no displaying here) to interprete the data you
> receive from forms. do whatever you need to do with your database etc. here.
> Place the objects you want to display in the request, the session or the
> servletcontext, so that it is accessible from a display JSP. Then forward the
> request to a display JSP appropriate for displaying whatever you need to display.
> I.e. there is a 1:n relation between servlet/logic-JSP and display-JSP. There
> shouldn't be a lot of code in the servlet. It should merely be used to call
> methods of other servlet independent objects. Only the servlet specific code has
> to be placed here.
> * display your stuff with a display JSP. As you put your objects in the request (or
> session, etc.). you can access them via <jsp:usebean>. In your display JSP make
> sure you have no or close to no scriptlets. Use a taglib for iteration and
> conditional execution (e.g. <customtag:foreach> and <customtag:if>). Write more
> custom tags for other special display tasks. Do not write tags for stuff related
> to application logic. Do not write too many tags.
>
>Why? If you follow the proposed way, you have a chance of achieving the following
>goals:
>
> * separate your application from the web interface (no app logic in the servlet,
> just the glue between the web and your app goes here, instead place the applogic
> in your app beans or business objects)
> * the glue/servlet code and the app code can be written and maintained by real
> programmers, not HTML guys (no offense, HTML guys, it is really difficult to do
> HTML and Java, but most people do only know to do either one really well)
> * the display JSP can be written and maintained by HTML guys who learn some extra
> stuff like iteration with custom tags and JSP expressions (e.g.
> <%=person.getName()%>)
> * JDBC is hidden, so not everybody has to know everything about the underlying
> tables and has to be an expert in how to efficiently do joins etc. Also you can
> reuse PreparedStatements (*in theory* that gives you a performance boost) and
> don't have to deal with SQL all that much
>
>Well, even if you don't follow 'the proposed way' you have a chance to achieve these
>goals :-)
>This is just my opinion about the whole thing if you want to do it with JSP/Servlets.
>It is certainly not the only way to go. Also there are still EJB and XML/XSL(T) and
>....
>
>cheers,
>
>-hendrik
>- - - - - - - - - - - - - - - - - - - - - - - - - - -
> tagtraum industries http://www.tagtraum.com/
> jo! small&smart 2.2 servletengine
> Java Server & Servlets The web-application book
> The WebApp Framework http://www.webapp.de/
>
>
>Thang Nguyen wrote:
>
>> Hi,
>>
>> I have this fundalmental question. I hope you can shed some lights for me. I am
>> looking to see what would be a common solution to my application.
>>
>> My project is a web based application which will retrieve values from the informix
>> database, manupulate them, and send the results back to the requestors. As far as
>> I understand, and was able to run a few examples, I noticed these:
>>
>> (1) JSP can use JDBC to communicate with database directly
>> (2) Servlet can use JDBC to communicate with database directly
>> (3) Service Beans can use JDBC to communicate with database directly
>> (4) JSP can call Servlet as well as Java Bean
>>
>> So, what should I use, since the scope of this project can be larger? I am
>> looking for these qualities: fast, easy to maintain, and simple.
>>
>> (1) just use JSP only, use HTML like tag for visual, and JDBDC directly
>> for accessing database?
>>
>> or
>> (2) use JSP and Servlets, use HTML like tag for visual, and Servlets (jdbc
>> embeded) for accessing database?
>>
>> or
>> (3) use JSP with Java Beans, use Visual Bean for visual and Service Bean
>> (jdbc embeded) for accessing database.?
>>
>> Please help. Thank you very much for your time.
>>
>> TN
>
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>Some relevant FAQs on JSP/Servlets can be found at:
>
> http://java.sun.com/products/jsp/faq.html
> http://www.esperanto.org.nz/jsp/jspfaq.html
> http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
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致
礼！
ycd
[EMAIL PROTECTED]
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To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
