Java Spring数据jpa：创建名为'；实体管理工厂&x27；

大家好，我是stackoverflow的新手，也是spring数据jpa的新手

我目前正在开发个人网站，我有一个问题

我正在使用：

爪哇8 弹簧靴1.5.2 Spring boot starter数据jpa 1.5.2和 MySQL连接器

当我只有一个@Entity时，它工作正常，Hibernate成功地创建了MySQL模式，但当添加一些具有关系的@Entity时，我遇到以下错误：

    org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1081) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:856) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:314) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    at fr.geekads.Application.main(Application.java:10) [classes/:na]
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.persistenceException(EntityManagerFactoryBuilderImpl.java:954) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:882) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60) ~[spring-orm-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:353) ~[spring-orm-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:370) ~[spring-orm-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:359) ~[spring-orm-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    ... 16 common frames omitted
Caused by: org.hibernate.MappingException: Could not determine type for: java.util.List, at table: user, for columns: [org.hibernate.mapping.Column(ads)]
    at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:431) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:398) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.mapping.Property.isValid(Property.java:225) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:595) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.mapping.RootClass.validate(RootClass.java:265) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.boot.internal.MetadataImpl.validate(MetadataImpl.java:329) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:443) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:879) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
    ... 22 common frames omitted

这是我的代码结构：

pom.xml：

<?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>fr.geekads</groupId>
    <artifactId>geekads</artifactId>
    <version>1.0.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</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-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

和Ad.java：

@Entity
@Table(name = "Ad")
public class Ad {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private String logical_id;
    private String title;
    private String logoUrl;
    private String shortDescription;
    private String description;

    @OneToOne
    private AdCategory category;

    private String postDate;
    private String lastUp;

    private Boolean putMoneyIntoPlay;

    private int geekCoins;
    private int views;

    @OneToOne
    private User user;

    @OneToOne
    private Project project;

    private Boolean allowComments;

    @OneToMany
    private List<Comment> comments;

    @OneToOne
    private AdType type;

    private String bannerUrl;
    private String startDate;
    private String endDate;
}

@实体
@表（name=“Ad”）
公共类广告{
@身份证
@GeneratedValue（策略=GenerationType.AUTO）
私人长id；
私有字符串逻辑标识；
私有字符串标题；
私有字符串logoUrl；
私有字符串短描述；
私有字符串描述；
@奥内托内
私人广告类别；
私有字符串postDate；
私人串；
私家布尔游戏；
私人国际geekCoins；
私人意见；
@奥内托内
私人用户；
@奥内托内
私人项目；
私有布尔allowComments；
@独身癖
私人名单评论；
@奥内托内
私有AdType类型；
私人字符串横幅；
私有字符串起始日期；
私有字符串结束日期；
}

我不明白为什么我会犯这个错误。。。我正在寻找一个为期2天的解决方案

---

如果您有想法，请提前感谢您的帮助

我终于找到了解决方案。是我的错

解释：

我考虑的是对象，而不是关系数据库方面

例如，在我的User.java中，我与我的Ad.java有一个关系，在我的Ad.java中，我与我的User.java有一个关系，这导致了笛卡尔积。因此Hibernate无法创建SQL架构

因此，我根据概念数据模型重构了代码，效果很好

现在，User.java不再引用Ad.java，Ad.java用@OneToOne引用User.java的@id

---

问题解决了！：）

您在

Ad

上有

@OneToOne

，但在

用户

上有

列出广告

。我不确定这是否有用，但您是否尝试将此

@OneToOne

更改为

@ManyToOne

？不起作用，但我遇到了一个新错误：org.springframework.beans.factory.BeanCreationException:创建名为“entityManagerFactory”的bean时出错，该bean在类路径资源中定义[org/springframework/boot/autoconfigure/orm/jpa/hibernatejpaaautoconfiguration.class]：调用init方法失败；嵌套异常为org.hibernate.AnnotationException:fr.geekads.model.User.ads上的OneToOne或ManyToOne引用未知实体：java.util.list这些关系中有没有应该是双向的？在这种情况下，将

mappedBy

放在所有相关的关系上。发布

persistence.xml

so people可以看到定义了哪些类there@NeilStockton事实上，这是由于我的双向关系。

@Entity
@Table(name = "Project")
public class Project {

    @Id
    private String name;

    private String logoUrl;
    private String shortDescription;
    private String description;
    private String projectUrl;

    private Boolean showContact;
    private String skype;
    private String facebook;
    private String twitter;
    private String linkedin;
    private String mail;

    @OneToOne
    private ProjectCategory category;

    @OneToOne
    private User owner;

    @OneToMany
    private List<User> members;

    @OneToMany
    private List<Ad> ads;

    private int geekCoins;
    private int views;
}

@Entity
@Table(name = "Comment")
public class Comment {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @OneToOne//(cascade = CascadeType.ALL, targetEntity = User.class)
    private User user;

    private String message;
    private String postDate;

    @OneToOne(targetEntity = Ad.class)
    private Long ad_id;
}

@Entity
@Table(name = "Ad")
public class Ad {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private String logical_id;
    private String title;
    private String logoUrl;
    private String shortDescription;
    private String description;

    @OneToOne
    private AdCategory category;

    private String postDate;
    private String lastUp;

    private Boolean putMoneyIntoPlay;

    private int geekCoins;
    private int views;

    @OneToOne
    private User user;

    @OneToOne
    private Project project;

    private Boolean allowComments;

    @OneToMany
    private List<Comment> comments;

    @OneToOne
    private AdType type;

    private String bannerUrl;
    private String startDate;
    private String endDate;
}