通过构造函数实例化Bean失败

Question

我最近刚刚开始学习如何使用vaadin创建web应用程序，而对web开发一无所知。我遵循了教程中的所有内容，但我出现了一个错误。我被这个错误困扰了好几天，我真的需要帮助。这是我在运行网络应用程序时遇到的错误。

2020-09-14 14:12:53.351 ERROR 7016 --- [nio-8080-exec-1] c.v.flow.router.InternalServerError      : There was an exception while trying to navigate to ''
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.vaadin.tutorial.crm.ui.MainView': Bean instantiation via constructor failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.vaadin.tutorial.crm.ui.MainView]: Constructor threw exception; nested exception is java.lang.IllegalStateException: BeanValidationBinder cannot be used because a JSR-303 Bean Validation implementation not found on the classpath or could not be initialized. Use Binder instead
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:313) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:294) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1356) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1203) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:307) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at com.vaadin.flow.spring.SpringInstantiator.getOrCreate(SpringInstantiator.java:117) ~[vaadin-spring-12.3.1.jar:na]
at com.vaadin.flow.di.Instantiator.createRouteTarget(Instantiator.java:160) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.lambda$getRouteTarget$1(AbstractNavigationStateRenderer.java:135) ~[flow-server-2.3.5.jar:2.3.5]
at java.base/java.util.Optional.orElseGet(Optional.java:369) ~[na:na]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.getRouteTarget(AbstractNavigationStateRenderer.java:134) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.sendBeforeEnterEventAndPopulateChain(AbstractNavigationStateRenderer.java:518) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.createChainIfEmptyAndExecuteBeforeEnterNavigation(AbstractNavigationStateRenderer.java:498) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.handle(AbstractNavigationStateRenderer.java:230) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.router.Router.handleNavigation(Router.java:249) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.router.Router.navigate(Router.java:220) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.router.Router.navigate(Router.java:186) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.router.Router.initializeUI(Router.java:93) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.server.BootstrapHandler.createAndInitUI(BootstrapHandler.java:1534) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.server.BootstrapHandler.synchronizedHandleRequest(BootstrapHandler.java:474) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:40) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1545) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:247) ~[flow-server-2.3.5.jar:2.3.5]
at com.vaadin.flow.spring.SpringServlet.service(SpringServlet.java:108) ~[vaadin-spring-12.3.1.jar:na]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:141) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:177) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:52) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.vaadin.tutorial.crm.ui.MainView]: Constructor threw exception; nested exception is java.lang.IllegalStateException: BeanValidationBinder cannot be used because a JSR-303 Bean Validation implementation not found on the classpath or could not be initialized. Use Binder instead
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:217) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:117) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:309) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
... 74 common frames omitted
Caused by: java.lang.IllegalStateException: BeanValidationBinder cannot be used because a JSR-303 Bean Validation implementation not found on the classpath or could not be initialized. Use Binder instead
at com.vaadin.flow.data.binder.BeanValidationBinder.<init>(BeanValidationBinder.java:85) ~[flow-data-2.3.5.jar:2.3.5]
at com.vaadin.flow.data.binder.BeanValidationBinder.<init>(BeanValidationBinder.java:61) ~[flow-data-2.3.5.jar:2.3.5]
at com.vaadin.tutorial.crm.ui.ContactForm.<init>(ContactForm.java:36) ~[classes/:na]
at com.vaadin.tutorial.crm.ui.MainView.<init>(MainView.java:29) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[na:na]
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:204) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
... 76 common frames omitted

这是错误中提到的类中的一行：

Binder<Contact>  binder = new BeanValidationBinder<>(Contact.class);

在这里，我包含了该类的更多代码。

public class ContactForm extends FormLayout {
private Contact contact;
TextField firstName = new TextField("First Name");
TextField lastName = new TextField("Last Name");
EmailField email = new EmailField("Email");
ComboBox<Contact.Status> status = new ComboBox<>("Status");
ComboBox<Company> company = new ComboBox<>("Company");
Button save = new Button("Save");
Button delete = new Button("Delete");
Button close = new Button("Close");
Binder<Contact>  binder = new BeanValidationBinder<>(Contact.class);

public ContactForm(List<Company> companies){
addClassName("contact-form");
binder.bindInstanceFields(this);
company.setItems(companies);
company.setItemLabelGenerator(Company::getName);
status.setItems(Contact.Status.values());
add(firstName,lastName,email,company,status,createButtonsLayout());
}

Answer 1

Vaadin没有提供内置的Bean验证实现——您需要在项目的依赖项中自己提供一个。来自文档：

要使用Bean验证注释，需要像Hibernate这样的JSR303实现类路径中可用的验证器。如果您的环境，例如Java EE容器，没有提供实现，您可以在Maven中使用以下依赖项：

<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
<version>5.4.1.Final</version>
</dependency>

Answer 2

如果使用spring boot parent，请在pom.xml中添加此依赖项>2.3

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