Vaadin 对象不是声明 class 的实例

Question

我正在尝试调用 class 中名为 (DataActions) 的方法到仪表板视图，以便网格能够接收方法执行后给定的对象，但仍然无法解决此错误（java.lang.IllegalArgumentException：对象不是声明class的实例）。

-Class(DataSession)是class负责打开数据库会话。 -Class (DataActions) 是 class 负责使用由（DataSession 对象）创建的会话从数据库中提取信息的方法 -方法 updateGrid 使用创建的对象调用 (DataActions) 中的方法。

本项目是用vaadin hello world示例项目创建的，所以使用了springboot（2.4.5版本）和vaadin flow（14.7.0版本）

--仪表板视图--

package com.example.application.views.dashboard;

import com.example.application.Controller.DataActions;
import com.vaadin.flow.component.grid.Grid;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.example.application.Model.PatientsTblEntity;
import com.vaadin.flow.router.Route;
import com.vaadin.flow.router.PageTitle;
import com.example.application.views.MainLayout;
import com.vaadin.flow.router.RouteAlias;

@PageTitle("Dashboard")
@Route(value = "dashboard", layout = MainLayout.class)
@RouteAlias(value = "", layout = MainLayout.class)
public class DashboardView extends VerticalLayout {

    Grid<PatientsTblEntity> patients_grid = new Grid<>(PatientsTblEntity.class);
    DataActions actions = new DataActions();
    public DashboardView(){
        addClassName("list-view");
        configureGrid();
        add(patients_grid);
        updateGrid();

    }




    /*
        -Configuring grid properties, so it can handle data coming from another function
     */
    public void configureGrid(){
        patients_grid.addClassName("contact-grid");
        patients_grid.setSizeFull();
//        patients_grid.setColumns("txtCode", "txtName", "dblAge", "datDateOfBirth", "datOfLasttVisit");
        patients_grid.getColumns().forEach(patientsTblEntityColumn -> {
            patientsTblEntityColumn.setAutoWidth(true);
        });
    }

    /*
        -Update grid with information coming from the database using actions from class DataActions
     */
    public void updateGrid(){
            patients_grid.setItems(actions.getAllPatientsList());


    }

}

--DataActions class--

package com.example.application.Controller;

import com.example.application.Model.PatientsTblEntity;
import org.hibernate.Session;

import java.util.List;

public class DataActions {
    public DataActions(){}
    DataSessions dataSessions = new DataSessions();
    /*
        -Variable where session is created
        -Created as a variable, so it can be opened and closed at ease in every function
     */
    private Session session = dataSessions.getSession();


    public List<PatientsTblEntity> getAllPatientsList(){
        session.beginTransaction();
        List<PatientsTblEntity> list = session.getSession().createQuery("FROM PatientsTblEntity P").getResultList();
        session.close();
        return list;
    }

--Pom.xml 文件--

<?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>
    <!-- Vaadin project from https://start.vaadin.com/project/a13f6a96-e47e-432d-bf78-e4e60571348e -->
    <groupId>com.example.application</groupId>
    <artifactId>asd-8</artifactId>
    <name>Project base for Spring Boot and Vaadin Flow</name>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <properties>
        <java.version>8</java.version>
        <vaadin.version>14.7.0</vaadin.version>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.5</version>
    </parent>

    <repositories>
        <!-- The order of definitions matters. Explicitly defining central here to make sure it has the highest priority. -->

        <!-- Main Maven repository -->
        <repository>
            <id>central</id>
            <url>https://repo.maven.apache.org/maven2</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <!-- Repository used by many Vaadin add-ons -->
        <repository>
            <id>Vaadin Directory</id>
            <url>https://maven.vaadin.com/vaadin-addons</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>

    <pluginRepositories>
        <!-- Main Maven repository -->
        <pluginRepository>
            <id>central</id>
            <url>https://repo.maven.apache.org/maven2</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

    <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>com.vaadin</groupId>
            <!-- Replace artifactId with vaadin-core to use only free components -->
            <artifactId>vaadin</artifactId>
            <exclusions>
                <!-- Webjars are only needed when running in Vaadin 13 compatibility mode -->
                <exclusion>
                    <groupId>com.vaadin.webjar</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.webjars.bowergithub.insites</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.webjars.bowergithub.polymer</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.webjars.bowergithub.polymerelements</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.webjars.bowergithub.vaadin</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.webjars.bowergithub.webcomponents</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-spring-boot-starter</artifactId>
            <exclusions>
                <!-- Excluding so that webjars are not included. -->
                <exclusion>
                    <groupId>com.vaadin</groupId>
                    <artifactId>vaadin-core</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.vaadin.artur</groupId>
            <artifactId>a-vaadin-helper</artifactId>
            <version>1.7.1</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-testbench</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.microsoft.sqlserver/mssql-jdbc -->
        <dependency>
            <groupId>com.microsoft.sqlserver</groupId>
            <artifactId>mssql-jdbc</artifactId>
            <version>9.2.1.jre8</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.5.7.Final</version>
        </dependency>


        <!-- Include JUnit 4 support for TestBench and others -->
        <dependency>
            <groupId>org.junit.vintage</groupId>
            <artifactId>junit-vintage-engine</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.hamcrest</groupId>
                    <artifactId>hamcrest-core</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>io.github.bonigarcia</groupId>
            <artifactId>webdrivermanager</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <defaultGoal>spring-boot:run</defaultGoal>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <!-- Clean build and startup time for Vaadin apps sometimes may exceed
                     the default Spring Boot's 30sec timeout.  -->
                <configuration>
                    <wait>500</wait>
                    <maxAttempts>240</maxAttempts>
                </configuration>
            </plugin>

            <!--
                Take care of synchronizing java dependencies and imports in
                package.json and main.js files.
                It also creates webpack.config.js if not exists yet.
            -->
            <plugin>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin-maven-plugin</artifactId>
                <version>${vaadin.version}</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>prepare-frontend</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <profiles>
        <profile>
            <!-- Production mode is activated using -Pproduction -->
            <id>production</id>
            <build>
                <plugins>
                    <plugin>
                        <groupId>com.vaadin</groupId>
                        <artifactId>vaadin-maven-plugin</artifactId>
                        <version>${vaadin.version}</version>
                        <executions>
                            <execution>
                                <goals>
                                    <goal>build-frontend</goal>
                                </goals>
                                <phase>compile</phase>
                            </execution>
                        </executions>
                        <configuration>
                            <productionMode>true</productionMode>
                        </configuration>
                    </plugin>
                </plugins>
            </build>
        </profile>

        <profile>
            <id>it</id>
            <build>
                <plugins>
                    <plugin>
                        <groupId>org.springframework.boot</groupId>
                        <artifactId>spring-boot-maven-plugin</artifactId>
                        <executions>
                            <execution>
                                <id>start-spring-boot</id>
                                <phase>pre-integration-test</phase>
                                <goals>
                                    <goal>start</goal>
                                </goals>
                            </execution>
                            <execution>
                                <id>stop-spring-boot</id>
                                <phase>post-integration-test</phase>
                                <goals>
                                    <goal>stop</goal>
                                </goals>
                            </execution>
                        </executions>
                    </plugin>

                    <!-- Runs the integration tests (*IT) after the server is started -->
                    <plugin>
                        <groupId>org.apache.maven.plugins</groupId>
                        <artifactId>maven-failsafe-plugin</artifactId>
                        <executions>
                            <execution>
                                <goals>
                                    <goal>integration-test</goal>
                                    <goal>verify</goal>
                                </goals>
                            </execution>
                        </executions>
                        <configuration>
                            <trimStackTrace>false</trimStackTrace>
                            <enableAssertions>true</enableAssertions>
                        </configuration>
                    </plugin>
                </plugins>
            </build>
        </profile>

    </profiles>
</project>

Answer 1

我找到了解决方案，我在方法所在的 class 中缺少注释 @Component，而我想要 [=] 实例的注释 @Autowired 14=] 待创建。

Vaadin 对象不是声明 class 的实例

Vaadin object is not an instance of declaring class

java

vaadin

pom.xml

maven

spring-boot