Question

我在创建文件中定义名为'userController'的bean时出错。不幸的是，我是Java和Spring的新手，所以无法理解如何解决所有这些问题。

在我的类“UserController”类中，构造函数和方法从未使用过（实际上我也不知道为什么）。我启动了我的DB PostgreSQL并尝试启动我的stpringBootproject，但失败了。如果有人可以帮助“我该怎么办”，那将是非常好的.. 我的环境： Linux Mint Intellij IDEA（社区）

这是我关于stackoverflow的第一个问题，所以如果我犯了一些错误，请通知我，我会很感激。

structure of my project

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班级代码

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界面 ```

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上课 ```

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();
    }

}

这是控制台的ERROR

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

Answer 1

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（堆栈跟踪中的最后一个“由...引起”）。在您的情况下，这是以下内容：

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，您在hibernate-core内手动添加了hibernate-entitymanager和pom.xml个依赖项，即使spring-boot-starter-data-jpa已经包含了这两个依赖项。

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>

另一个问题是您对@Id实体使用了错误的User注释。与@Entity和@GeneratedValue注释一样，@Id注释应来自javax.persistence.Id，而不是您正在使用的注释。

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，您应该使它们实现您的接口并正确地对它们进行注释（例如，使用@Repository）。

但是，在您的情况下，不需要它。它没有被Spring接收，你也没有使用它。即使现在一切正常，您也可以安全地删除此类。

您的saveUser()方法也存在实际问题。编写REST API时，通常不希望从控制台（Scanner）读取，而是从API中获取输入。

然而，这与问题中提到的问题不同，我建议您在准备好之后再创建一个新问题。在此之前，检查有关如何在控制器中检索输入的文档可能会很有趣。

Answer 2

“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，但是在这种情况下，应该使它们实现您的接口并正确地注释它们（例如，使用@Repository）。< / p>

但是，在您的情况下，您不需要它。 Spring尚未拾取它，而且您也不会使用它。即使现在一切正常，您也可以安全地删除此类。”

在上面的行中，您提到的@Repository不是必需的。就我而言，将其删除也可以，但是请您告诉我为什么不需要这样做。我只是想知道，因为我正在努力理解和学习。

创建名为'userController'的bean在文件中定义时出错

2 个答案: