A.12. web.xml

The web.xml file is a standard descriptor of a Java web application and should be created for the Middleware, Web Client and Web Portal blocks.

In an application project, web.xml files are located in the web/WEB-INF folders of the corresponding modules.

  • web.xml for the Middleware block (core project module) has the following content:

    <?xml version="1.0" encoding="UTF-8" standalone="no"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         version="3.0">
    <!-- Application properties config files -->
    <context-param>
        <param-name>appPropertiesConfig</param-name>
        <param-value>
            classpath:com/company/sample/app.properties
            /WEB-INF/local.app.properties
            "file:${app.home}/local.app.properties"
        </param-value>
    </context-param>
    <!--Application components-->
    <context-param>
        <param-name>appComponents</param-name>
        <param-value>com.haulmont.cuba com.haulmont.reports</param-value>
    </context-param>
    <listener>
        <listener-class>com.haulmont.cuba.core.sys.AppContextLoader</listener-class>
    </listener>
    <servlet>
        <servlet-name>remoting</servlet-name>
        <servlet-class>com.haulmont.cuba.core.sys.remoting.RemotingServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>remoting</servlet-name>
        <url-pattern>/remoting/*</url-pattern>
    </servlet-mapping>
</web-app>

    The context-param elements define initializing parameters for the ServletContext object of the current web application. The list of application components is defined in the appComponents parameter, the list of application property files is defined in the appPropertiesConfig parameter.

    The listener element defines a listener class implementing the ServletContextListener interface. The Middleware block uses the AppContextLoader class as a listener. This class initializes the AppContext.

    Servlet descriptions follow, including the RemotingServlet class, mandatory for the Middleware block. This servlet is accessible via the /remoting/* URL, and is related to the remote access container (see remoting-spring.xml).

  • web.xml for the Web Client block (web project module) has the following content:

    <?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         version="3.0">

    <!-- Application properties config files -->
    <context-param>
        <param-name>appPropertiesConfig</param-name>
        <param-value>
            classpath:com/company/demo/web-app.properties
            /WEB-INF/local.app.properties
            "file:${app.home}/local.app.properties"
        </param-value>
    </context-param>
    <!--Application components-->
    <context-param>
        <param-name>appComponents</param-name>
        <param-value>com.haulmont.cuba com.haulmont.reports</param-value>
    </context-param>

    <listener>
        <listener-class>com.vaadin.server.communication.JSR356WebsocketInitializer</listener-class>
    </listener>
    <listener>
        <listener-class>com.haulmont.cuba.web.sys.WebAppContextLoader</listener-class>
    </listener>

    <servlet>
        <servlet-name>app_servlet</servlet-name>
        <servlet-class>com.haulmont.cuba.web.sys.CubaApplicationServlet</servlet-class>
        <async-supported>true</async-supported>
    </servlet>
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>com.haulmont.cuba.web.sys.CubaDispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/dispatch/*</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>app_servlet</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

    <filter>
        <filter-name>cuba_filter</filter-name>
        <filter-class>com.haulmont.cuba.web.sys.CubaHttpFilter</filter-class>
        <async-supported>true</async-supported>
    </filter>
    <filter-mapping>
        <filter-name>cuba_filter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
</web-app>

    In the context-param elements, the lists of application components and application property files are defined.

    The Web Client block uses the WebAppContextLoader class as a ServletContextListener.

    The JSR356WebsocketInitializer listener is required for WebSockets protocol support.

    CubaApplicationServlet provides the generic user interface implementation based on the Vaadin framework.

    CubaDispatcherServlet initializes an additional Spring context for Spring MVC controllers. This context is configured in the dispatcher-spring.xml file.