在Spring Java中创建实体时出错[重复]

Question

package com.example.app.entity;

import javax.persistence.*;
import java.util.List;

@Entity
@Table(name = "events")
public class Event {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private long id;

  private String name;
  private List < String > games;
  private List < User > players;
  private double latitude;
  private double longitude;
  private String description;
  private User owner;

  public User getOwner() {
    return owner;
  }
  public void setOwner(User owner) {
    this.owner = owner;
  }

  public String getDescription() {
    return description;
  }
  public void setDescription(String description) {
    this.description = description;
  }

  public double getLatitude() {
    return latitude;
  }
  public void setLatitude(double latitude) {
    this.latitude = latitude;
  }

  public double getLongitude() {
    return longitude;
  }
  public void setLongitude(double longitude) {
    this.longitude = longitude;
  }

  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }

  public long getId() {
    return id;
  }

  public void setId(long id) {
    this.id = id;
  }

  public List < String > getGames() {
    return games;
  }

  public void setGames(List < String > games) {
    this.games = games;
  }

  public List < User > getPlayers() {
    return players;
  }

  public void setPlayers(List < User > players) {
    this.players = players;
  }
}

下面是我得到的错误：

    org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'eventServiceImpl': Unsatisfied dependency expressed through field 'eventRepository'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'eventRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Failed to create query for method public abstract com.example.app.entity.Event com.example.app.repository.EventRepository.findOneByUsername(java.lang.String)! No property username found for type Event!
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1344) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:312) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:760) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:868) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:388) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at com.example.app.AppApplication.main(AppApplication.java:12) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'eventRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Failed to create query for method public abstract com.example.app.entity.Event com.example.app.repository.EventRepository.findOneByUsername(java.lang.String)! No property username found for type Event!
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1710) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:583) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:312) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
... 19 common frames omitted
Caused by: java.lang.IllegalArgumentException: Failed to create query for method public abstract com.example.app.entity.Event com.example.app.repository.EventRepository.findOneByUsername(java.lang.String)! No property username found for type Event!
at org.springframework.data.jpa.repository.query.PartTreeJpaQuery.<init>(PartTreeJpaQuery.java:82) ~[spring-data-jpa-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$CreateQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:103) ~[spring-data-jpa-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$CreateIfNotFoundQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:208) ~[spring-data-jpa-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$AbstractQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:79) ~[spring-data-jpa-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.lookupQuery(RepositoryFactorySupport.java:553) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.lambda$mapMethodsToQuery$1(RepositoryFactorySupport.java:546) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) ~[na:1.8.0_161]
at java.util.Iterator.forEachRemaining(Iterator.java:116) ~[na:1.8.0_161]
at java.util.Collections$UnmodifiableCollection$1.forEachRemaining(Collections.java:1049) ~[na:1.8.0_161]
at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801) ~[na:1.8.0_161]
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) ~[na:1.8.0_161]
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_161]
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_161]
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_161]
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_161]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.mapMethodsToQuery(RepositoryFactorySupport.java:548) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.lambda$new$0(RepositoryFactorySupport.java:538) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at java.util.Optional.map(Optional.java:215) ~[na:1.8.0_161]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.<init>(RepositoryFactorySupport.java:538) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:317) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.lambda$afterPropertiesSet$3(RepositoryFactoryBeanSupport.java:287) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.util.Lazy.getNullable(Lazy.java:141) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.util.Lazy.get(Lazy.java:63) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.afterPropertiesSet(RepositoryFactoryBeanSupport.java:290) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean.afterPropertiesSet(JpaRepositoryFactoryBean.java:102) ~[spring-data-jpa-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1769) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1706) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
... 29 common frames omitted
Caused by: org.springframework.data.mapping.PropertyReferenceException: No property username found for type Event!
at org.springframework.data.mapping.PropertyPath.<init>(PropertyPath.java:90) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:350) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:330) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.mapping.PropertyPath.lambda$from$0(PropertyPath.java:283) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at java.util.concurrent.ConcurrentMap.computeIfAbsent(ConcurrentMap.java:324) ~[na:1.8.0_161]
at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:265) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:248) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.query.parser.Part.<init>(Part.java:81) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.query.parser.PartTree$OrPart.lambda$new$0(PartTree.java:250) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) ~[na:1.8.0_161]
at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175) ~[na:1.8.0_161]
at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948) ~[na:1.8.0_161]
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) ~[na:1.8.0_161]
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_161]
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_161]
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_161]
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_161]
at org.springframework.data.repository.query.parser.PartTree$OrPart.<init>(PartTree.java:251) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.query.parser.PartTree$Predicate.lambda$new$0(PartTree.java:380) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) ~[na:1.8.0_161]
at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175) ~[na:1.8.0_161]
at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948) ~[na:1.8.0_161]
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) ~[na:1.8.0_161]
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_161]
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_161]
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_161]
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_161]
at org.springframework.data.repository.query.parser.PartTree$Predicate.<init>(PartTree.java:381) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.repository.query.parser.PartTree.<init>(PartTree.java:96) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.data.jpa.repository.query.PartTreeJpaQuery.<init>(PartTreeJpaQuery.java:76) ~[spring-data-jpa-2.0.5.RELEASE.jar:2.0.5.RELEASE]
... 55 common frames omitted


Process finished with exit code 1

下面是我的文件夹和资源的映像,如果有助于解决此问题：

Answer 1

这是关键：

Failed to create query for method public abstract com.example.app.entity.Event com.example.app.repository.EventRepository.findOneByUsername(java.lang.String)! No property username found for type Event!

对于类event没有属性username，有一个名为eventrepository的存储库，它具有QueryMethodFindONEBYusername（注意FindByusername)。

因此，您应该为event声明一个属性username(String)，或者从存储库中删除这个QueryMethod（因为没有username属性它是完全没用的），当然，它会抛出这个错误。