java - Spring - 无法执行 CommandLineRunner : @Bean

Question

我是 Spring 新手，遇到以下异常

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-06-12 21:48:27.204 ERROR 13289 --- [           main] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Failed to execute CommandLineRunner
        at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:816) [spring-boot-2.1.5.RELEASE.jar:2.1.5.RELEASE]

这是我运行应用程序的类

   @SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    CommandLineRunner init(UserRepository userRepository) {
        return args -> {
            Stream.of("John", "Julie", "Jennifer", "Helen", "Rachel").forEach(name -> {
                User user = new User(name, name.toLowerCase() + "@domain.com");
                userRepository.save(user);
            });
            userRepository.findAll().forEach(System.out::println);
        };
    }
}

这是我正在遵循的指南:here

我评论了init方法中有关Stream.of的部分，并放置了一个System.out.println("hello");并且工作正常。所以问题是Stream。

      .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.5.RELEASE)

2019-06-12 22:48:13.015  INFO 13817 --- [           main] springboot.angularest.Application        : Starting Application on Marta-Strasse.local with PID 13817 (/Users/Simone/IdeaProjects/angularest/target/classes started by Simone in /Users/Simone/IdeaProjects/angularest)
2019-06-12 22:48:13.021  INFO 13817 --- [           main] springboot.angularest.Application        : No active profile set, falling back to default profiles: default
2019-06-12 22:48:15.430  INFO 13817 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data repositories in DEFAULT mode.
2019-06-12 22:48:15.555  INFO 13817 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 114ms. Found 1 repository interfaces.
2019-06-12 22:48:16.100  INFO 13817 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$d61747a1] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2019-06-12 22:48:16.473  INFO 13817 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2019-06-12 22:48:16.518  INFO 13817 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2019-06-12 22:48:16.519  INFO 13817 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.19]
2019-06-12 22:48:16.703  INFO 13817 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2019-06-12 22:48:16.703  INFO 13817 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 3524 ms
2019-06-12 22:48:16.922  INFO 13817 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2019-06-12 22:48:17.057  INFO 13817 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2019-06-12 22:48:17.131  INFO 13817 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [
    name: default
    ...]
2019-06-12 22:48:17.208  INFO 13817 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate Core {5.3.10.Final}
2019-06-12 22:48:17.220  INFO 13817 --- [           main] org.hibernate.cfg.Environment            : HHH000206: hibernate.properties not found
2019-06-12 22:48:17.364  INFO 13817 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.0.4.Final}
2019-06-12 22:48:17.507  INFO 13817 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2019-06-12 22:48:17.975  INFO 13817 --- [           main] org.hibernate.tuple.PojoInstantiator     : HHH000182: No default (no-argument) constructor for class: springboot.angularest.model.User (class must be instantiated by Interceptor)
2019-06-12 22:48:18.322  INFO 13817 --- [           main] o.h.t.schema.internal.SchemaCreatorImpl  : HHH000476: Executing import script 'org.hibernate.tool.schema.internal.exec.ScriptSourceInputNonExistentImpl@6451a288'
2019-06-12 22:48:18.326  INFO 13817 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2019-06-12 22:48:18.982  INFO 13817 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2019-06-12 22:48:19.030  WARN 13817 --- [           main] aWebConfiguration$JpaWebMvcConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2019-06-12 22:48:19.351  INFO 13817 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2019-06-12 22:48:19.359  INFO 13817 --- [           main] springboot.angularest.Application        : Started Application in 7.321 seconds (JVM running for 9.837)
2019-06-12 22:48:19.474  INFO 13817 --- [           main] o.h.h.i.QueryTranslatorFactoryInitiator  : HHH000397: Using ASTQueryTranslatorFactory
2019-06-12 22:48:19.579  INFO 13817 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-06-12 22:48:19.591 ERROR 13817 --- [           main] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Failed to execute CommandLineRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:816) ~[spring-boot-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:797) ~[spring-boot-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:324) ~[spring-boot-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) ~[spring-boot-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) ~[spring-boot-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at springboot.angularest.Application.main(Application.java:21) ~[classes/:na]
Caused by: org.springframework.orm.jpa.JpaSystemException: No default constructor for entity:  : springboot.angularest.model.User; nested exception is org.hibernate.InstantiationException: No default constructor for entity:  : springboot.angularest.model.User
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:351) ~[spring-orm-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:253) ~[spring-orm-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:527) ~[spring-orm-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:61) ~[spring-tx-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:242) ~[spring-tx-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:153) ~[spring-tx-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:138) ~[spring-data-jpa-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at com.sun.proxy.$Proxy83.findAll(Unknown Source) ~[na:na]
    at springboot.angularest.Application.lambda$init$1(Application.java:33) ~[classes/:na]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:813) ~[spring-boot-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    ... 5 common frames omitted
Caused by: org.hibernate.InstantiationException: No default constructor for entity:  : springboot.angularest.model.User
    at org.hibernate.tuple.PojoInstantiator.instantiate(PojoInstantiator.java:85) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.tuple.PojoInstantiator.instantiate(PojoInstantiator.java:105) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.tuple.entity.AbstractEntityTuplizer.instantiate(AbstractEntityTuplizer.java:673) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.persister.entity.AbstractEntityPersister.instantiate(AbstractEntityPersister.java:4950) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.internal.SessionImpl.instantiate(SessionImpl.java:1682) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.internal.SessionImpl.instantiate(SessionImpl.java:1666) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.instanceNotYetLoaded(Loader.java:1663) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.getRow(Loader.java:1561) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:731) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.processResultSet(Loader.java:990) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.doQuery(Loader.java:948) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:340) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.doList(Loader.java:2689) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.doList(Loader.java:2672) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2506) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.Loader.list(Loader.java:2501) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:504) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:395) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:220) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1508) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.query.internal.AbstractProducedQuery.doList(AbstractProducedQuery.java:1537) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1505) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.query.Query.getResultList(Query.java:132) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.hibernate.query.criteria.internal.compile.CriteriaQueryTypeQueryAdapter.getResultList(CriteriaQueryTypeQueryAdapter.java:74) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.findAll(SimpleJpaRepository.java:313) ~[spring-data-jpa-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.findAll(SimpleJpaRepository.java:74) ~[spring-data-jpa-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na]
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:359) ~[spring-data-commons-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:200) ~[spring-data-commons-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:644) ~[spring-data-commons-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:608) ~[spring-data-commons-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.lambda$invoke$3(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59) ~[spring-data-commons-2.1.8.RELEASE.jar:2.1.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:295) ~[spring-tx-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.1.7.RELEASE.jar:5.1.7.RELEASE]
    ... 16 common frames omitted

2019-06-12 22:48:19.598  INFO 13817 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2019-06-12 22:48:19.599  INFO 13817 --- [           main] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2019-06-12 22:48:19.600  INFO 13817 --- [           main] .SchemaDropperImpl$DelayedDropActionImpl : HHH000477: Starting delayed evictData of schema as part of SessionFactory shut-down'
2019-06-12 22:48:19.612  INFO 13817 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2019-06-12 22:48:19.621  INFO 13817 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.

Process finished with exit code 1

通过对 Stream.of() 进行调试，我得到了:

 private void callRunner(CommandLineRunner runner, ApplicationArguments args) {
    try {
        runner.run(args.getSourceArgs());
    } catch (Exception var4) {
        throw new IllegalStateException("Failed to execute CommandLineRunner", var4);
    }
}

Answer 1

如果您提供整个堆栈跟踪以及导致 IllegalStateException 的错误，将会有很大帮助。此外，您可以在 Debug模式下运行应用程序以获取更多信息。

我只能猜测问题出在用户实体上。

您的用户看起来像文档中的那样吗:

@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;
    private final String name;
    private final String email;

    public User(String name, String email) {
      this.name = name;
      this.email = email;
    }

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

    public long getId() {
      return id;
    }

    public String getName() {
      return name;
    }

    public String getEmail() {
      return email;
    }
}

编辑:这是罪魁祸首引起的: org.springframework.orm.jpa.JpaSystemException: No default constructor for entity: : springboot.angularest.model.User;嵌套异常是org.hibernate.InstantiationException:没有实体的默认构造函数::springboot.angularest.model.User

请尝试使用默认构造函数的User类。创建 JPA 实体时，必须考虑将对其执行的反射。因此，有时需要创建 getter、setter 和构造函数，即使您从未调用过它们。:

@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    public long id;
    public String name;
    public String email;

    public User() {}

    public User(String name, String email) {
      this.name = name;
      this.email = email;
    }
}