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我有一个使用 web.xml 和 Spring 的工作 Vaadin 18 原型。

该原型用于使用 web.xml 和 vanilla Spring 的大型 web 应用程序的端口。我想在不删除 web.xml 或使用 Spring Boot 的情况下更新前端。

它在 Vaadin 18.0.6 中运行良好，但在 Vaadin 22.0.0 中启动失败：

java.lang.IllegalStateException: The application Lookup instance is not found in the interface com.vaadin.flow.server.VaadinContext instance. It means that the container has not executed Lookup initialization code: so either the container is not Servlet 3.0 compatible or project configuration is broken.
    at com.vaadin.flow.server.startup.ApplicationConfiguration.lambda$get$0 (ApplicationConfiguration.java:58)
    at com.vaadin.flow.server.VaadinServletContext.getAttribute (VaadinServletContext.java:73)
    at com.vaadin.flow.server.startup.ApplicationConfiguration.get (ApplicationConfiguration.java:50)

初步挖掘表明不再支持disable.automatic.servlet.registration上下文参数。

使原型在 Vaadin 22 中工作需要什么？

这是 web.xml：

<?xml version="1.0" encoding="ISO-8859-1"?>
<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"
     metadata-complete="false">

<!-- NOTE: metadata-complete="false" is required, in order to invoke
           ClassLoaderAwareServletContainerInitializer subclasses (DevModeInitializer etc) -->

<context-param>
    <!-- disables registration of the VaadinServlet. This is required as it is registered via AppServlet -->
    <param-name>disable.automatic.servlet.registration</param-name>
    <param-value>true</param-value>
</context-param>

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<servlet>
    <servlet-name>AppServlet</servlet-name>
    <servlet-class>org.example.AppServlet</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>AppServlet</servlet-name>
    <url-pattern>/app</url-pattern>
    <url-pattern>/app/*</url-pattern>
</servlet-mapping>

</web-app>

以及对应的servlet：

/**
 * Servlet to wire Vaadin into web.xml.
 */
public class AppServlet extends HttpServlet {

    private SpringServlet delegate;

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        ServletContext servletContext = getServletContext();
        WebApplicationContext context = WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext);
        delegate = new SpringServlet(context, false);
        delegate.init(config);
    }

    @Override
    public void destroy() {
        if (delegate != null) {
            delegate.destroy();
        }
    }

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        delegate.service(request, response);
    }
}
4

1 回答 1

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根据此评论，解决方案是将com.vaadin.flow.spring.VaadinApplicationConfiguration bean 添加到applicationContext.xml。

这需要<context:annotation-config/>才能工作，例如：

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd 
                           http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">

    <context:annotation-config/>

    <bean class="com.vaadin.flow.spring.VaadinApplicationConfiguration"/>
</beans>

如果不想使用<context:annotation-config/> ，可以直接添加VaadinApplicationConfiguration创建的 bean ：

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean class="com.vaadin.flow.spring.SpringApplicationConfigurationFactory"/>
    <bean class="com.vaadin.flow.spring.SpringLookupInitializer.SpringApplicationContextInit"/>
</beans>

不建议这样做，因为 SpringApplicationContextInit 在 Vaadin 内部。

于 2022-01-02T06:03:05.730 回答