自从Vaadin 14在本周二发布以来，我已经尝试在我的Spring-boot Web应用程序中使用它。在我的pom中包含依赖项.xml工作正常。 运行应用程序也可以正常工作。但是，一旦我通过浏览器连接到本地主机，我就会收到以下消息：
2019-07-05 13:46:33.743 WARN 7812 --- [nio-8080-exec-1] c.v.f.s.DefaultDeploymentConfiguration :
====================================================================
Vaadin is running in DEBUG MODE.
Add productionMode=true to web.xml to disable debug features.
====================================================================
2019-07-05 13:46:33.744 WARN 7812 --- [nio-8080-exec-1] c.v.f.s.DefaultDeploymentConfiguration :
====================================================================
Running in Vaadin 13 (Flow 1) compatibility mode.
This mode uses webjars/Bower for client side dependency management and HTML imports for dependency loading.
The default mode in Vaadin 14+ (Flow 2+) is based on npm for dependency management and JavaScript modules for dependency inclusion.
See http://vaadin.com/docs for more information.
====================================================================
如错误中所述，显然Vaadin 14未正常运行，并且正在设置回Vaadin 13兼容模式。 我现在想知道这是否与我的代码或我的依赖项版本有关。如何查看/找出应用程序重置为 Vaadin 13 兼容模式的原因？有没有办法在新的Vaadin 14上稳定运行应用程序？ 下面包括我的pom.xml和我的代码，这只是发送点击消息的简单启动按钮。
我已经尝试通过更改应用程序属性来禁用 Vaadin 的调试模式。可悲的是，这根本不起作用。
Pom.xml：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>vaadinneuneu</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>vaadinneuneu</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>11</java.version>
<vaadin.version>14.0.0.rc3</vaadin.version>
</properties>
<repositories>
<!-- Repository needed for prerelease versions of Vaadin -->
<repository>
<id>vaadin-prereleases</id>
<url>https://maven.vaadin.com/vaadin-prereleases</url>
<snapshots><enabled>false</enabled></snapshots>
</repository>
</repositories>
<pluginRepositories>
<!-- Repository needed for prerelease versions of Vaadin -->
<pluginRepository>
<id>vaadin-prereleases</id>
<url>https://maven.vaadin.com/vaadin-prereleases</url>
<snapshots><enabled>false</enabled></snapshots>
</pluginRepository>
</pluginRepositories>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-bom</artifactId>
<version>14.0.0.rc3</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
法典：
package com.example.vaadinneuneu;
import com.vaadin.flow.component.button.Button;
import com.vaadin.flow.component.notification.Notification;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.vaadin.flow.router.Route;
import com.vaadin.flow.server.PWA;
@Route(value = "home")
@PWA(name = "Kram", shortName = "Base")
public class MainView extends VerticalLayout {
public MainView() {
Button button = new Button("Click Me!",
event -> Notification.show("Clicked!"));
add(button);
}
}
您应该将vaadin-maven-pluginprepare-frontend和build-frontend目标添加到您的pom.xml中。
<plugin>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-maven-plugin</artifactId>
<version>${vaadin.version}</version>
<executions>
<execution>
<goals>
<goal>prepare-frontend</goal>
<goal>build-frontend</goal>
</goals>
</execution>
</executions>
</plugin>
默认情况下，在将版本更新到 14.x.x 时使用 Vaadin 10-13 创建的项目中，它将以兼容模式运行，一切都应该像以前一样工作。您看到的警告不是错误，只是对正在使用哪种模式的说明，并且对于将 Vaadin 版本更改为 14.x.x 的现有项目，预计
会出现如果要升级到基于 npm 的新模式进行客户端依赖项管理和用于依赖项包含的 JavaScript 模块，请查看 Vaadin 14 迁移指南。