我创建文件中定义的名为“userController”的 bean 时出错。不幸的是，我对 Java 和 Spring 完全陌生，所以不明白如何解决所有这些问题。
在我的类“UserController”中，从未使用过类构造函数和方法(实际上我也不知道为什么)。我启动了 DB PostgreSQL 并尝试启动我的 stspringBoot 项目，但失败了。如果有人可以帮助“我应该做什么”，那就太好了。 我的环境: Linux薄荷 Intellij IDEA(社区)
这是我在 stackoverflow 上的第一个问题，所以如果我犯了一些错误，请告知我，我将不胜感激。
这是我的 POM 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>
<groupId>io.cursor</groupId>
<artifactId>app-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>app-demo</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.1.4.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.2.3.Final</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</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>
这是UserController代码
package io.cursor.appdemo.web;
import io.cursor.appdemo.model.User;
import io.cursor.appdemo.repository.UserRepository;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.Scanner;
@RestController
@Slf4j
public class UserController {
private final UserRepository repository;
@Autowired
UserController (UserRepository repository) {
this.repository = repository;
}
@GetMapping("/")
public void saveUser() {
try (Scanner scanner = new Scanner(System.in)) {
log.info("Input name and email");
String name = scanner.next();
String email = scanner.next();
User user = new User();
user.setUsername(name);
user.setEmail(email);
repository.save(user);
}
}
}
User类代码
package io.cursor.appdemo.model;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
import org.springframework.data.annotation.Id;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
@Entity
@Getter
@Setter
@ToString
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String username;
private String email;
}
UserRepository 接口(interface)
````
package io.cursor.appdemo.repository;
import io.cursor.appdemo.model.User;
import org.springframework.data.jpa.repository.JpaRepository;
public interface UserRepository extends JpaRepository<User,Long> {
}
UserRepositoryImpl 类
````
package io.cursor.appdemo.repository.impl;
import io.cursor.appdemo.model.User;
import io.cursor.appdemo.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import java.util.List;
public class UserRepositoryImpl {
@Autowired
private UserRepository userRepository;
public User save(User user) {
return userRepository.save(user);
}
public List<User> findAll() {
return userRepository.findAll();
}
}
这里是控制台的错误
2018-05-30 11:32:45.549 INFO 9669 --- [ main] io.cursor.appdemo.AppDemoApplication : Starting AppDemoApplication on maks with PID 9669 (/home/maks/IdeaProjects/lecture22part2/app-demo/target/classes started by maks in /home/maks/IdeaProjects/lecture22part2/app-demo)
2018-05-30 11:32:45.564 INFO 9669 --- [ main] io.cursor.appdemo.AppDemoApplication : No active profile set, falling back to default profiles: default
2018-05-30 11:32:46.084 INFO 9669 --- [ main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@358c99f5: startup date [Wed May 30 11:32:46 EEST 2018]; root of context hierarchy
2018-05-30 11:32:51.065 INFO 9669 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$6943c491] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2018-05-30 11:32:52.235 INFO 9669 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2018-05-30 11:32:52.366 INFO 9669 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2018-05-30 11:32:52.367 INFO 9669 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.31
2018-05-30 11:32:52.400 INFO 9669 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib]
2018-05-30 11:32:52.658 INFO 9669 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2018-05-30 11:32:52.659 INFO 9669 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 6595 ms
2018-05-30 11:32:53.072 INFO 9669 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/]
2018-05-30 11:32:53.090 INFO 9669 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-05-30 11:32:53.091 INFO 9669 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-05-30 11:32:53.092 INFO 9669 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-05-30 11:32:53.092 INFO 9669 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2018-05-30 11:32:53.237 WARN 9669 --- [ main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userController' defined in file [/home/maks/IdeaProjects/lecture22part2/app-demo/target/classes/io/cursor/appdemo/web/UserController.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userRepositoryImpl': Unsatisfied dependency expressed through field 'userRepository'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userRepository': Post-processing of merged bean definition failed; nested exception is java.lang.NoSuchMethodError: javax.persistence.PersistenceContext.synchronization()Ljavax/persistence/SynchronizationType;
2018-05-30 11:32:53.254 INFO 9669 --- [ main] o.apache.catalina.core.StandardService : Stopping service [Tomcat]
2018-05-30 11:32:53.310 INFO 9669 --- [ main] ConditionEvaluationReportLoggingListener :
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-05-30 11:32:53.322 ERROR 9669 --- [ main] o.s.boot.SpringApplication : Application run failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userController' defined in file [/home/maks/IdeaProjects/lecture22part2/app-demo/target/classes/io/cursor/appdemo/web/UserController.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userRepositoryImpl': Unsatisfied dependency expressed through field 'userRepository'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userRepository': Post-processing of merged bean definition failed; nested exception is java.lang.NoSuchMethodError: javax.persistence.PersistenceContext.synchronization()Ljavax/persistence/SynchronizationType;
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:729) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:192) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1274) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1131) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:541) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:760) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at io.cursor.appdemo.AppDemoApplication.main(AppDemoApplication.java:10) [classes/:na]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userRepositoryImpl': Unsatisfied dependency expressed through field 'userRepository'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userRepository': Post-processing of merged bean definition failed; nested exception is java.lang.NoSuchMethodError: javax.persistence.PersistenceContext.synchronization()Ljavax/persistence/SynchronizationType;
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1348) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:578) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:304) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:815) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:721) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
... 19 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userRepository': Post-processing of merged bean definition failed; nested exception is java.lang.NoSuchMethodError: javax.persistence.PersistenceContext.synchronization()Ljavax/persistence/SynchronizationType;
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
... 35 common frames omitted
Caused by: java.lang.NoSuchMethodError: javax.persistence.PersistenceContext.synchronization()Ljavax/persistence/SynchronizationType;
at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor$PersistenceElement.<init>(PersistenceAnnotationBeanPostProcessor.java:653) ~[spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.lambda$buildPersistenceMetadata$1(PersistenceAnnotationBeanPostProcessor.java:435) ~[spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.util.ReflectionUtils.doWithLocalMethods(ReflectionUtils.java:522) ~[spring-core-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.buildPersistenceMetadata(PersistenceAnnotationBeanPostProcessor.java:420) ~[spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.findPersistenceMetadata(PersistenceAnnotationBeanPostProcessor.java:394) ~[spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(PersistenceAnnotationBeanPostProcessor.java:332) ~[spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyMergedBeanDefinitionPostProcessors(AbstractAutowireCapableBeanFactory.java:1020) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
... 44 common frames omitted
Process finished with exit code 1
最佳答案
即使初始错误消息提到它无法创建您的 UserController bean，您也应该始终检查根本原因(堆栈跟踪中最后一个“Caused by”)。对于您的情况，如下:
Caused by: java.lang.NoSuchMethodError: javax.persistence.PersistenceContext.synchronization()Ljavax/persistence/SynchronizationType;
这通常表明您拥有的库版本与预期版本不同。在您的情况下，您手动将 hibernate-core 和 hibernate-entitymanager 依赖项包含在 pom.xml 中，即使它们都已经是感谢 spring-boot-starter-data-jpa 的帮助。
要解决此问题，您可以删除以下依赖项:
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.1.4.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.2.3.Final</version>
</dependency>
另一个问题是您为 User 实体使用了错误的 @Id 注释。就像 @Entity 和 @GenerateValue 注释一样，@Id 注释应该来自 javax.persistence.Id ，而不是您正在使用的。
我发现的最后一个问题是您编写了自己的UserRepositoryImpl。自定义存储库用于高级查询，但在这种情况下，您应该让它们实现您的接口(interface)并正确注释它们(例如，使用 @Repository)。
但是，就您的情况而言，您不需要它。 Spring 不会接收它，而且你也不会使用它。即使现在一切正常，您也可以安全地删除此类。
<小时/>您的 saveUser() 方法还存在一个实用问题。编写 REST API 时，您通常不想从控制台 (Scanner) 读取数据，而是从 API 获取输入。
但是，这是一个与问题中提到的问题不同的问题，我建议您在准备好后创建一个关于它的新问题。在此之前，查看有关如何在 Controller 中检索输入的文档可能会很有趣。
关于java - 创建文件中定义的名称为 'userController' 的 bean 时出错，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/50600243/