Vaadin 按钮单击侦听器错误

Question

我正在尝试在 mysql 和 vaadin 之间建立连接，在实施项目时，我收到以下错误消息：

MyUI 类：

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.ui.Button;
import com.vaadin.ui.Label;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;

@Theme("mytheme")
public class MyUI extends UI {

    @Override
    protected void init(VaadinRequest vaadinRequest) {
        final VerticalLayout layout = new VerticalLayout();

        final TextField name = new TextField();
        name.setCaption("Type your name here:");

        Button button = new Button("Click Me");
        button.addClickListener(e -> {
            layout.addComponent(new Label("Thanks " + name.getValue() + ", it works!"));
        });

        layout.addComponents(name, button);

        setContent(layout);
    }

    @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
    @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
    public static class MyUIServlet extends VaadinServlet {
    }
}

连接类：

import com.vaadin.addon.sqlcontainer.SQLContainer;
import com.vaadin.addon.sqlcontainer.query.QueryDelegate;
import com.vaadin.data.util.sqlcontainer.connection.JDBCConnectionPool;
import com.vaadin.data.util.sqlcontainer.connection.SimpleJDBCConnectionPool;
import com.vaadin.data.util.sqlcontainer.query.TableQuery;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Connect {
     private JDBCConnectionPool connect = null;
    private SQLContainer containe=null;
    public void connects()
    {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            connect=  new SimpleJDBCConnectionPool("com.mysql.jdbc.Driver", "jdb:mysql://localhost:3306/quanlysinhvien", "root", "");
            System.out.println("checkok");
        } catch (SQLException ex) {
            Logger.getLogger(Connect.class.getName()).log(Level.SEVERE, null, ex);
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(Connect.class.getName()).log(Level.SEVERE, null, ex);
        }
    TableQuery tq = new TableQuery("user", connect);
    tq.setVersionColumn("username");
        try {
            containe = new SQLContainer((QueryDelegate) (tq));
        } catch (SQLException ex) {
            Logger.getLogger(Connect.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

}

POM：

<?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>

    <groupId>checkConnet</groupId>
    <artifactId>ccs</artifactId>
    <packaging>war</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>ccs</name>

    <prerequisites>
        <maven>3</maven>
    </prerequisites>

    <properties>
        <vaadin.version>8.3.1</vaadin.version>
        <vaadin.plugin.version>8.3.1</vaadin.plugin.version>
        <jetty.plugin.version>9.3.9.v20160517</jetty.plugin.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <!-- If there are no local customizations, this can also be "fetch" or "cdn" -->
        <vaadin.widgetset.mode>local</vaadin.widgetset.mode>
    </properties>

    <repositories>
        <repository>
            <id>vaadin-addons</id>
            <url>http://maven.vaadin.com/vaadin-addons</url>
        </repository>
    </repositories>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin-bom</artifactId>
                <version>${vaadin.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-server</artifactId>
            <version>7.7.13</version>
            <type>jar</type>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-push</artifactId>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-client-compiled</artifactId>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-themes</artifactId>
        </dependency>
        <dependency>
            <groupId>org.vaadin.addons</groupId>
            <artifactId>vaadin-sqlcontainer</artifactId>
            <version>1.1.0</version>
            <type>jar</type>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.45</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.0.0</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                    <!-- Exclude an unnecessary file generated by the GWT compiler. -->
                    <packagingExcludes>WEB-INF/classes/VAADIN/widgetsets/WEB-INF/**</packagingExcludes>
                </configuration>
            </plugin>
            <plugin>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin-maven-plugin</artifactId>
                <version>${vaadin.plugin.version}</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>update-theme</goal>
                            <goal>update-widgetset</goal>
                            <goal>compile</goal>
                            <!-- Comment out compile-theme goal to use on-the-fly theme compilation -->
                            <goal>compile-theme</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <runTarget>http://localhost:8080/ccs</runTarget>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-clean-plugin</artifactId>
                <version>3.0.0</version>
                <!-- Clean up also any pre-compiled themes -->
                <configuration>
                    <filesets>
                        <fileset>
                            <directory>src/main/webapp/VAADIN/themes</directory>
                            <includes>
                                <include>**/styles.css</include>
                                <include>**/styles.scss.cache</include>
                            </includes>
                        </fileset>
                    </filesets>
                </configuration>
            </plugin>

            <!-- The Jetty plugin allows us to easily test the development build by
                running jetty:run on the command line. -->
            <plugin>
                <groupId>org.eclipse.jetty</groupId>
                <artifactId>jetty-maven-plugin</artifactId>
                <version>${jetty.plugin.version}</version>
                <configuration>
                    <scanIntervalSeconds>2</scanIntervalSeconds>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <profiles>
        <profile>
            <!-- Vaadin pre-release repositories -->
            <id>vaadin-prerelease</id>
            <activation>
                <activeByDefault>false</activeByDefault>
            </activation>

            <repositories>
                <repository>
                    <id>vaadin-prereleases</id>
                    <url>http://maven.vaadin.com/vaadin-prereleases</url>
                </repository>
                <repository>
                    <id>vaadin-snapshots</id>
                    <url>https://oss.sonatype.org/content/repositories/vaadin-snapshots/</url>
                    <releases>
                        <enabled>false</enabled>
                    </releases>
                    <snapshots>
                        <enabled>true</enabled>
                    </snapshots>
                </repository>
            </repositories>
            <pluginRepositories>
                <pluginRepository>
                    <id>vaadin-prereleases</id>
                    <url>http://maven.vaadin.com/vaadin-prereleases</url>
                </pluginRepository>
                <pluginRepository>
                    <id>vaadin-snapshots</id>
                    <url>https://oss.sonatype.org/content/repositories/vaadin-snapshots/</url>
                    <releases>
                        <enabled>false</enabled>
                    </releases>
                    <snapshots>
                        <enabled>true</enabled>
                    </snapshots>
                </pluginRepository>
            </pluginRepositories>
        </profile>
    </profiles>
</project>

---

编辑说明：以上来源摘自initial archive OP linked on google drive

Answer 1

主要问题是您试图混合来自 2 个不同 Vaadin 版本的模块，8.3.1 和 7.7.13，并且它们之间存在重大变化。尽管在编译时以某种方式神奇地一切看起来都很好，但在运行时expected addClickListener method can't be found

最初我认为这可能是一个诚实的错误，但后来我注意到您的 Connect 类正在从 v7 导入内容：

import com.vaadin.data.util.sqlcontainer.connection.JDBCConnectionPool;
import com.vaadin.data.util.sqlcontainer.connection.SimpleJDBCConnectionPool;
import com.vaadin.data.util.sqlcontainer.query.TableQuery;

您必须确定要使用的版本，并仅从该版本导入模块。然后，根据您的项目限制（例如：没有 spring、没有 jpa、vaadin 7 等），您可以查看有关如何将您的应用程序连接到 MySQL 的教程，例如：

• https://spring.io/guides/gs/crud-with-vaadin/ [spring boot, spring data & jpa]
• https://vaadin.com/blog/building-a-web-ui-for-mysql-databases-in-plain-java- [spring boot & spring jdbc 模板]

spring 示例是开始学习的好地方，因为它们需要最少的配置，而且您不必通过连接池等重新发明轮子。但就像我说的，根据您的限制选择合适的教程。

P.S. 进行更改后，请务必在运行项目之前运行mvn clean，以免旧工件干扰...