v8 to v14 routing problems

Marco36 · June 19, 2019, 10:59pm

Hi all,

I’m migrating from Vaadin8 to Vaadin14.
I read the docs, but I can’t find the solution to the following problem. Can anyone please help me?

This is my web.xml:

<web-app>

    <context-param>
        <param-name>productionMode</param-name>
        <param-value>false</param-value>
    </context-param>

    <servlet>
        <servlet-name>ReportMachine servlet</servlet-name>
        <servlet-class>com.marcozanon.reportmachine.AUiServlet</servlet-class>
        <init-param>
            <param-name>UI</param-name>
            <param-value>com.marcozanon.reportmachine.AApplicationUi</param-value>
        </init-param>
<!--
        <init-param>
            <param-name>widgetset</param-name>
            <param-value>com.marcozanon.reportmachine.widgetset.CustomWidgetSet</param-value>
        </init-param>
-->
        <init-param>
            <param-name>closeIdleSessions</param-name>
            <param-value>false</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>ReportMachine servlet</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

    <session-config>
        <session-timeout>5</session-timeout>
    </session-config>

    <context-param>
        <param-name>heartbeatInterval</param-name>
        <param-value>60</param-value>
    </context-param>

</web-app>

If I compile and run the application, everything I see is:

Could not navigate to ''

Reason: Couldn't find route for ''

Available routes:

This detailed message is only shown when running in development mode.

I thought this was due to missing @Route annotations, so I added one to the default class AView:

@com.vaadin.flow.router.Route("")
@PreserveOnRefresh
public class AView extends VerticalLayout {

  public AView() {
      this.add(new Text("TEST"));
  }

}

but the error still shows up.

If I change web.xml to:

    <servlet-mapping>
        <servlet-name>ReportMachine servlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

(i.e.: no wildcards in url-pattern), then the error goes away and I see a blank page.
No way AView’s constructor is run.

Any ideas? I read the documentation and the examples, maybe it’s just a small detail, but I can’t figure it out…

Thanks a lot,
MZ

Denis48 · June 20, 2019, 5:48am

You need a view annotated with @Route , that’s true.

Generally that’s enough.
I believe you have issues because you are using a specific config with web.xml file.

We don’t recommend to use a custom UI. The UI class is still available in the application
but application should use a default UI class otherwise some unexpected things may happen.

I would recommend to avoid using web.xml at all.
Try to start with https://github.com/vaadin/skeleton-starter-flow which has the minimal configuration
to start V14 application.

Marco36 · June 20, 2019, 1:23pm

Hi Denis, and thanks for replying.

I decided to follow your advice, i.e.: reduce web.xml at minimum. I will need a custom servlet, but not at the moment, so I put web.xml like this:

<web-app>

    <context-param>
        <param-name>productionMode</param-name>
        <param-value>false</param-value>
    </context-param>

    <session-config>
        <session-timeout>5</session-timeout>
    </session-config>

    <context-param>
        <param-name>heartbeatInterval</param-name>
        <param-value>60</param-value>
    </context-param>

</web-app>

Then I selected the default target:

@com.vaadin.flow.router.Route("")
@SuppressWarnings("serial")
public class AUi extends VerticalLayout implements ErrorHandler {

    public AUi() {
		// code here...
	}

}

Unfortunately, AUi’s constructor is never run.
Instead, all I see when I connect to localhost:8081 (or localhost:8081/) is Jetty listing some directory content (I can’t understand which directory: not my .war file).

Is there anything else I’m missing?

The project you pointed me to simply adds a @Route on MainView, so I can’t find where the problem is here…

Thanks very much for your help,
MZ

Marco36 · June 20, 2019, 8:46pm

I made some tests and it seems the Route annotation is completely ignored in my code above…

Maybe Jetty (9.4.14) can’t read it?!

Thanks,
MZ

Marco36 · June 20, 2019, 9:09pm

Ok, I got it: I completely removed web.xml from the .war file, and it works!

Thanks Denis for your help.

I still don’t understand why the documentation says that web.xml is not required, while it seems to me it is concretely banned…

Thanks,
MZ

Denis48 · June 21, 2019, 7:10am

If you see some issues with documentation please create a ticket.
It will help us to improve it.

Marco36 · June 21, 2019, 11:30am

Done: https://github.com/vaadin/flow-and-components-documentation/issues/642.

Thanks,
MZ

Johannes · November 25, 2019, 11:08am

This worked fine for me (web.xml version 3.1)

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                             http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1">

        <context-param>
            <param-name>productionMode</param-name>
            <param-value>false</param-value>
        </context-param>

        <session-config>
            <session-timeout>5</session-timeout>
        </session-config>

        <context-param>
            <param-name>heartbeatInterval</param-name>
            <param-value>20</param-value>
        </context-param>

</web-app>

Marco36 · December 10, 2019, 1:17pm

Johannes Tuikkala:
This worked fine for me (web.xml version 3.1)

It didn’t work for me: no errors, but the web.xml file was completely ignored (I put it into src/main/webapp/WEB-INF and it was included in the final .war package),

thanks,

MZ

Yash4 · February 26, 2020, 10:41am

Marco Zanon:
Hi all,

I’m migrating from Vaadin8 to Vaadin14.
I read the docs, but I can’t find the solution to the following problem. Can anyone please help me?

This is my web.xml:

<web-app>

    <context-param>
        <param-name>productionMode</param-name>
        <param-value>false</param-value>
    </context-param>

    <servlet>
        <servlet-name>ReportMachine servlet</servlet-name>
        <servlet-class>com.marcozanon.reportmachine.AUiServlet</servlet-class>
        <init-param>
            <param-name>UI</param-name>
            <param-value>com.marcozanon.reportmachine.AApplicationUi</param-value>
        </init-param>
<!--
        <init-param>
            <param-name>widgetset</param-name>
            <param-value>com.marcozanon.reportmachine.widgetset.CustomWidgetSet</param-value>
        </init-param>
-->
        <init-param>
            <param-name>closeIdleSessions</param-name>
            <param-value>false</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>ReportMachine servlet</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

    <session-config>
        <session-timeout>5</session-timeout>
    </session-config>

    <context-param>
        <param-name>heartbeatInterval</param-name>
        <param-value>60</param-value>
    </context-param>

</web-app>

If I compile and run the application, everything I see is:

Could not navigate to ''

Reason: Couldn't find route for ''

Available routes:

This detailed message is only shown when running in development mode.

I thought this was due to missing @Route annotations, so I added one to the default class AView:

@com.vaadin.flow.router.Route("")
@PreserveOnRefresh
public class AView extends VerticalLayout {

  public AView() {
      this.add(new Text("TEST"));
  }

}

but the error still shows up.

If I change web.xml to:

    <servlet-mapping>
        <servlet-name>ReportMachine servlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

(i.e.: no wildcards in url-pattern), then the error goes away and I see a blank page.
No way AView’s constructor is run.

Any ideas? I read the documentation and the examples, maybe it’s just a small detail, but I can’t figure it out…

Thanks a lot,
MZ

Hey! I have the same problem. I am trying to run the program which is given over here → https://vaadin.com/docs/v14/flow/advanced/tutorial-dynamic-content.html

And what I get is Vaadin every time tries to find the route inside the @Route and does not get the urlPatterns inside the @WebServlet.

What can be the problem? your help will be greatly appreciated!
Thanks!