The content of element type “struts-config” must match “(datasource?,form-beans?

Question

I wrote a small struts application with a login page and registration page. If I login I get a success page. If i register, i will check the password and confirm password fileds if they match i get a success page else failure page.

I did not use any database. I wrote the required Form Beans, Action Classes of those.

In struts-config.xml it is showing an error at the <struts-config> tag:

"The content of element type “struts-config” must match “(datasource?,form-beans?,global-forwards?,action-mapping?)"

How to resolve this problem? I am using Eclipse as my IDE.

Answer 1

Your struts-config.xml file is invalid.

Struts-config.xml is an XML file and as such can be validated against a DTD or an XML-Schema.

The error you are seeing in Eclipse is a result of the struts-config.xml file being validated against its DTD and the validation fails. Most likely it is expecting your tags to be in a specific order and you didn't write them that way, you added tags that are not specified in the DTD, you misspelled some tag etc.

Look at the struts-config DTD and then at your struts-config.xml file to see where they differ.

P.S. there are more versions of the DTD so make sure you are looking at the right one.

http://struts.apache.org/dtds/struts-config_1_0.dtd
http://struts.apache.org/dtds/struts-config_1_1.dtd
http://struts.apache.org/dtds/struts-config_1_2.dtd
http://struts.apache.org/dtds/struts-config_1_3.dtd
http://struts.apache.org/dtds/struts-config_1_4.dtd

Answer 2

Yes, the struts-config.xml is invalid according to the schema, but as the app is working, it's only a validation issue. To expand on why it is invalid in the context of the order of the child elements - If the validator is telling you that...

The content of element type “struts-config” must match “(datasource?,form-beans?,global-forwards?,action-mapping?")

...then that means that e.g. (reduced examples for brevity):

<struts-config>
  <datasource>...</datasource>
  <form-beans>...</form-beans>
  <global-forwards>...</global-forwards>
  <action-mapping>...</action-mapping>
</struts-config>

...is a valid implementation of the schema, while e.g. ...

<struts-config>
  <datasource>...</datasource>
  <global-forwards>...</global-forwards>
  <form-beans>...</form-beans>
  <action-mapping>...</action-mapping>
</struts-config>

...is not. This, by the way, is due to the fact that the Struts 1.0 DTD in question says...

<!ELEMENT struts-config (data-sources?,form-beans?,global-forwards?,action-mappings?)>

...and by that demands a certain order of child elements. This is not something that the DTD authors do inadvertently, but due to fact that:

Declaring unordered lists with occurrence constraints in DTD will often result in long or complicated looking declarations. ¹

Answer 3

The elements' order matter. For example <form-beans></form-beans> element must be before <global-forwards></global-forwards> element etc.

Answer 4

I am using struts-config_1_3.dtd. I also got the same error in struts-config.xml when I added <global-forwards> tag in struts-config.xml.

("The content of element type “struts-config” must match “(datasource?,form-beans?,global-forwards?,action-mapping?)")

I added <global-forwards> tag after <action-mapping> tag, because of that it was throwing error. As the error description says, the order of the tags should be

<datasource></datasource>

<form-beans></form-beans>

<global-forwards></global-forwards>

<action-mapping></action-mapping>

So i changed my <global-forwards> before <action-mapping>. And it worked for me.

Hope this information help someone.