web app web.xml error [duplicate]

问题

I am getting an error in my GWT application being developed in Eclipse. It's in the web.xml file. Here's the error:

The content of element type "web-app" must match "(icon?,display-   name?,description?,distributable?,context-
     param*,filter*,filter-mapping*,listener*,servlet*,servlet-mapping*,session-config?,mime-mapping*,welcome-
     file-list?,error-page*,taglib*,resource-env-ref*,resource-ref*,security-constraint*,login-config?,security-
     role*,env-entry*,ejb-ref*,ejb-local-ref*)".

I have seen numerous posts about this and the problem is the order of the elements of the file, but that fix doesn't work for me (I have also tried putting all the <servlet-mapping> tags right after the corresponding <servlet>, it did not work either)

My web.xml file :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>

  <servlet>
    <servlet-name>dispatch</servlet-name>
    <servlet-class>com.yachtcloser.server.DispatchServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet>
    <servlet-name>upload</servlet-name>
    <servlet-class>com.yachtcloser.server.UploadServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet> 

  <servlet>
    <servlet-name>download</servlet-name>
    <servlet-class>com.yachtcloser.server.DownloadServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet>
    <servlet-name>login</servlet-name>
    <servlet-class>com.yachtcloser.server.LoginServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
    <servlet-name>dispatch</servlet-name>
    <url-pattern>/dispatch.do</url-pattern>
  </servlet-mapping>

  <servlet-mapping>
    <servlet-name>upload</servlet-name>
    <url-pattern>/upload.do</url-pattern>
  </servlet-mapping>

  <servlet-mapping>
    <servlet-name>download</servlet-name>
    <url-pattern>/download.do</url-pattern>
  </servlet-mapping>

  <servlet-mapping>
    <servlet-name>login</servlet-name>
    <url-pattern>/login.do</url-pattern>
  </servlet-mapping>

  <!-- Default page to serve -->
  <welcome-file-list>
    <welcome-file>Yc.html</welcome-file>
  </welcome-file-list>

</web-app>

Are there any other ways of tracking this error; other files that are linked to this?

回答1:

well, as per new format of DTD web-app tag might contains following tags. <!ELEMENT web-app (icon?, display-name?, description?, distributable?, context-param*, filter*, filter-mapping*, listener*, servlet*, servlet-mapping*, session-config?, mime-mapping*, welcome-file-list?, error-page*, taglib*, resource-env-ref*, resource-ref*, security-constraint*, login-config?, security-role*, env-entry*, ejb-ref*, ejb-local-ref*)>

above mentioned icon, display-name, description, distributable....etc are in the same order as they have mentioned in the DTD file.

e.g. if you put description tag before display-name it gives error.

回答2:

I deleted the file and pasted the text from the old one into a new file with the same name and now there's no errors.

回答3:

Just for a reference: A SelectAll->Cut->Save->Paste->Save also fixes the problem. Probably there is a line ending character issue.

回答4:

I followed the suggestion for "copy all" - "cut" - "paste" - "save" and this seemed to clear up the message. I found that in the "pasted" version all tabs had been converted to spaces.

So it seems that the web.xml validator in Eclipse does not like tabs.

回答5:

The error itself gives you the clue. The order of the elements in your web.xml should follow the order specified in the error.

<displayname>
</displayname>
<description>
</description>

....... like this the elements should be in order as it says in the error.

来源：https://stackoverflow.com/questions/6603910/web-app-web-xml-error

标签

servlets

web.xml