Question

我使用来自Internet的示例，然后尝试从Spring Boot 1.5.10.RELEASE升级到2.0.0.RC1。该应用程序适用于Spring Boot 版本1.5.10.RELEASE，但版本2.0.0.RC1有错误。

项目目录结构：

源代码：https://github.com/donhuvy/sample_boot3 文件 pom.xml

<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>com.example</groupId>
    <artifactId>spring_boot_hibernate</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <packaging>war</packaging>
    <properties>
        <start-class>spring-boot-example.Application</start-class>
    </properties>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <!--<version>1.5.10.RELEASE</version>-->
        <version>2.0.0.RC1</version>

    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.apache.tomcat</groupId>
                    <artifactId>tomcat-jdbc</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
        </dependency>
    </dependencies>

    <repositories>
        <repository>
            <id>spring-repo</id>
            <name>Spring Repository</name>
            <url>https://repo.spring.io/release</url>
        </repository>
        <repository>
            <id>spring-snapshot</id>
            <name>Spring Snapshot Repository</name>
            <url>https://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestone</id>
            <name>Spring Milestone Repository</name>
            <url>https://repo.spring.io/milestone</url>
        </repository>
    </repositories>
</project>

文件 application.properties

server.port=8081

spring.datasource.url=jdbc:mysql://localhost:3306/vy
spring.datasource.username=root
spring.datasource.password=123456
# Keep the connection alive if idle for a long time (needed in production)
spring.datasource.testWhileIdle=true
spring.datasource.validationQuery=SELECT 1
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=update
spring.jpa.hibernate.naming-strategy=org.hibernate.cfg.ImprovedNamingStrategy
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect

文件 BeanConfig.java

package com.example;

import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.persistence.EntityManagerFactory;

@Configuration
public class BeanConfig {

    @Autowired
    private EntityManagerFactory entityManagerFactory;

    @Bean
    public SessionFactory getSessionFactory() {
        if (entityManagerFactory.unwrap(SessionFactory.class) == null) {
            throw new NullPointerException("factory is not a hibernate factory");
        }
        return entityManagerFactory.unwrap(SessionFactory.class);
    }

}

错误发生在以下行：

if (entityManagerFactory.unwrap(SessionFactory.class) == null) {

文件 UserController.java

package com.example.controller;

import com.example.model.UserDetails;
import com.example.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import java.util.List;

@Controller
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping(value = "/list", method = RequestMethod.GET)
    public ResponseEntity<List<UserDetails>> userDetails() {
        List<UserDetails> userDetails = userService.getUserDetails();
        return new ResponseEntity<List<UserDetails>>(userDetails, HttpStatus.OK);
    }

}

档案 UserDaoImpl.java

package com.example.dao.impl;

import com.example.dao.UserDao;
import com.example.model.UserDetails;
import org.hibernate.Criteria;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.util.List;

@Component
public class UserDaoImpl implements UserDao {

    @Autowired
    private SessionFactory sessionFactory;

    public List<UserDetails> getUserDetails() {
        Criteria criteria = sessionFactory.openSession().createCriteria(UserDetails.class);
        return criteria.list();
    }

}

档案 UserDao.java

package com.example.dao;

import com.example.model.UserDetails;

import java.util.List;

public interface UserDao {

    List<UserDetails> getUserDetails();

}

档案 UserDetails.java

package com.example.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table
public class UserDetails {

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

    @Column
    private String firstName;

    @Column
    private String lastName;

    @Column
    private String email;

    @Column
    private String password;

    public int getId() {
        return id;
    }

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

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}

文件 UserServiceImpl.java

package com.example.service.impl;

import com.example.dao.UserDao;
import com.example.model.UserDetails;
import com.example.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    public List<UserDetails> getUserDetails() {
        return userDao.getUserDetails();

    }

}

错误（完整内容：https://gist.github.com/donhuvy/a0199d73d660442a8e595a05963e7b8f）

/Library/Java/JavaVirtualMachines/jdk-9.0.4.jdk/Contents/Home/bin/java -agentlib:jdwp=transport=dt_socket,address=127.0.0.1:49901,suspend=y,server=n --illegal-access=warn -XX:TieredStopAtLevel=1 -noverify -Dspring.output.ansi.enabled=always -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=49900 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Djava.rmi.server.hostname=127.0.0.1 -Dspring.liveBeansView.mbeanDomain -Dspring.application.admin.enabled=true -javaagent:/Users/donhuvy/Library/Caches/IntelliJIdea2017.3/captureAgent/debugger-...
WARNING: Illegal reflective access by org.springframework.cglib.core.ReflectUtils$1 (file:/Users/donhuvy/.m2/repository/org/springframework/spring-core/5.0.3.RELEASE/spring-core-5.0.3.RELEASE.jar) to method java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain)
2018-02-20 07:56:04.273  INFO 1944 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$1e62766c] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)

.... 2018-02-20 07：56：04.538 INFO 1944 --- [主要] ConditionEvaluationReportLoggingListener：

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-02-20 07:56:04.848 ERROR 1944 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'beanConfig': Unsatisfied dependency expressed through field 'entityManagerFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getSessionFactory' defined in class path resource [com/example/BeanConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.hibernate.SessionFactory]: Circular reference involving containing bean 'beanConfig' - consider declaring the factory method as static for independence from its containing instance. Factory method 'getSessionFactory' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1344) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:312) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:868) ~[spring-context-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:138) ~[spring-boot-2.0.0.RC1.jar:2.0.0.RC1]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) [spring-boot-2.0.0.RC1.jar:2.0.0.RC1]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:388) [spring-boot-2.0.0.RC1.jar:2.0.0.RC1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.0.RC1.jar:2.0.0.RC1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.0.RC1.jar:2.0.0.RC1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234) [spring-boot-2.0.0.RC1.jar:2.0.0.RC1]
    at com.example.Application.main(Application.java:10) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getSessionFactory' defined in class path resource [com/example/BeanConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.hibernate.SessionFactory]: Circular reference involving containing bean 'beanConfig' - consider declaring the factory method as static for independence from its containing instance. Factory method 'getSessionFactory' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:587) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1250) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1099) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:312) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    ... 19 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.hibernate.SessionFactory]: Circular reference involving containing bean 'beanConfig' - consider declaring the factory method as static for independence from its containing instance. Factory method 'getSessionFactory' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:579) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    ... 31 common frames omitted
Caused by: java.lang.NullPointerException: null
    at com.example.BeanConfig.getSessionFactory(BeanConfig.java:18) ~[classes/:na]
    at com.example.BeanConfig$$EnhancerBySpringCGLIB$$54b5def4.CGLIB$getSessionFactory$0(<generated>) ~[classes/:na]
    at com.example.BeanConfig$$EnhancerBySpringCGLIB$$54b5def4$$FastClassBySpringCGLIB$$bcb3b797.invoke(<generated>) ~[classes/:na]
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) ~[spring-core-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:361) ~[spring-context-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    at com.example.BeanConfig$$EnhancerBySpringCGLIB$$54b5def4.getSessionFactory(<generated>) ~[classes/:na]
    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:564) ~[na:na]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.0.3.RELEASE.jar:5.0.3.RELEASE]
    ... 32 common frames omitted

Disconnected from the target VM, address: '127.0.0.1:49901', transport: 'socket'

Process finished with exit code 1

如何解决？

Answer 1

在BeanConfig中，您应该通过EntityManager注入JPA @PersistenceUnit，而不是@Autowired。

并删除getSessionFactory，因为Hibernate SessionFactory已在内部创建，您始终可以打开EntityManagerFactory。

所以，它应该是这样的：

@Configuration
public class BeanConfig {

    @PersistenceUnit
    EntityManagerFactory emf;

}

Answer 2

档案BeanConfig.java

package com.example;

import org.hibernate.SessionFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;

@Configuration
public class BeanConfig {

    @PersistenceUnit
    EntityManagerFactory entityManagerFactory;

    @Bean
    public SessionFactory getSessionFactory() {
        if (entityManagerFactory.unwrap(SessionFactory.class) == null) {
            throw new NullPointerException("factory is not a hibernate factory");
        }
        return entityManagerFactory.unwrap(SessionFactory.class);
    }

}

关于使用方法getSessionFactory

的示例

package com.example.dao.impl;

import com.example.dao.UserDao;
import com.example.model.UserDetails;
import org.hibernate.Criteria;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.util.List;

@Component
public class UserDaoImpl implements UserDao {

    @Autowired
    private SessionFactory sessionFactory;

    public List<UserDetails> getUserDetails() {
        Criteria criteria = sessionFactory.openSession().createCriteria(UserDetails.class);
        return criteria.list();
    }

}

（这是Hibernate 5.2.13.Final，Spring Boot 2.0.0.RC2和Java 9.0.4的一个工作示例）

BeanInstantiationException：无法实例化[org.hibernate.SessionFactory]：涉及包含bean的循环引用

2 个答案: