Java JPA：与确切类型实体的一对一关系_Java_Jpa_Jpa 2.0

Java JPA：与确切类型实体的一对一关系

java jpa

Java JPA：与确切类型实体的一对一关系,java,jpa,jpa-2.0,Java,Jpa,Jpa 2.0,假设您有以下数据库表： CREATE TABLE IF NOT EXISTS USER ( USER_NAME VARCHAR(20) NOT NULL, FIRST_NAME VARCHAR(50) NOT NULL, SECOND_NAME VARCHAR(50) NOT NULL DEFAULT '', SURNAME VARCHAR(50) NOT

假设您有以下数据库表：

CREATE TABLE IF NOT EXISTS USER (
    USER_NAME               VARCHAR(20) NOT NULL,
    FIRST_NAME              VARCHAR(50) NOT NULL,
    SECOND_NAME             VARCHAR(50) NOT NULL DEFAULT '',
    SURNAME                 VARCHAR(50) NOT NULL,
    BIRTH_DATE              DATE NOT NULL,
    BIRTH_GENDER            ENUM ('M', 'F') NOT NULL,
    CREATION_TIMESTAMP      TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    CREATED_BY              VARCHAR(20) NOT NULL,
    LAST_UPDATE_TIMESTAMP   TIMESTAMP NULL ON UPDATE CURRENT_TIMESTAMP,
    LAST_UPDATED_BY         VARCHAR(20),
    DELETION_TIMESTAMP      TIMESTAMP NULL,
    DELETED_BY              VARCHAR(20),

    PRIMARY KEY (USER_NAME),
    FOREIGN KEY (CREATED_BY) REFERENCES USER(USER_NAME),
    FOREIGN KEY (LAST_UPDATED_BY) REFERENCES USER(USER_NAME),
    FOREIGN KEY (DELETED_BY) REFERENCES USER(USER_NAME)
) CHARACTER SET utf8;

我拥有以下JPA实体，如下所示：

/**
 * @author Buhake Sindi
 *
 */
@Entity
@Table(name="USER")
@Access(AccessType.FIELD)
public class User implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1600376007707987934L;

    @Id
    @Column(name="USER_NAME", nullable=false)
    private String id;

    @Column(name="FIRST_NAME", nullable=false)
    private String firstName;

    @Column(name="SECOND_NAME", nullable=false)
    private String secondName;

    @Column(name="SURNAME", nullable=false)
    private String surname;

    @Temporal(TemporalType.DATE)
    @Column(name="BIRTH_DATE", nullable=false)
    private Date birthDate;

    @Column(name="BIRTH_GENDER", columnDefinition="ENUM('M', 'F')", nullable=false)
    @Enumerated(EnumType.STRING)
    private Gender birthGender;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name="CREATION_TIMESTAMP", insertable=false, updatable=false, nullable=false)
    private Date creationTimestamp;

    @OneToOne(fetch=FetchType.LAZY)
    @JoinColumn(name="CREATED_BY", insertable=true, updatable=false, nullable=false)
    private User createdBy;

    /* (non-Javadoc)
     * @see za.co.sindi.entity.IDBasedEntity#getId()
     */
    public String getId() {
        // TODO Auto-generated method stub
        return id;
    }

    /* (non-Javadoc)
     * @see za.co.sindi.entity.IDBasedEntity#setId(java.io.Serializable)
     */
    public void setId(String id) {
        // TODO Auto-generated method stub
        this.id = id;
    }

    /**
     * @return the firstName
     */
    public String getFirstName() {
        return firstName;
    }

    /**
     * @param firstName the firstName to set
     */
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    /**
     * @return the secondName
     */
    public String getSecondName() {
        return secondName;
    }

    /**
     * @param secondName the secondName to set
     */
    public void setSecondName(String secondName) {
        this.secondName = secondName;
    }

    /**
     * @return the surname
     */
    public String getSurname() {
        return surname;
    }

    /**
     * @param surname the surname to set
     */
    public void setSurname(String surname) {
        this.surname = surname;
    }

    /**
     * @return the birthDate
     */
    public Date getBirthDate() {
        return birthDate;
    }

    /**
     * @param birthDate the birthDate to set
     */
    public void setBirthDate(Date birthDate) {
        this.birthDate = birthDate;
    }

    /**
     * @return the birthGender
     */
    public Gender getBirthGender() {
        return birthGender;
    }

    /**
     * @param birthGender the birthGender to set
     */
    public void setBirthGender(Gender birthGender) {
        this.birthGender = birthGender;
    }


    /* (non-Javadoc)
     * @see za.co.sindi.entity.AbstractIdentifiableAuditableEntity#getCreationTimestamp()
 */
    @Override
    public Date getCreationTimestamp() {
    // TODO Auto-generated method stub
    return creationTimestamp;
}

/* (non-Javadoc)
 * @see za.co.sindi.entity.AbstractIdentifiableAuditableEntity#setCreationTimestamp(java.util.Date)
 */
@Override
public void setCreationTimestamp(Date creationTimestamp) {
    // TODO Auto-generated method stub
    this.creationTimestamp = creationTimestamp;
}

/* (non-Javadoc)
 * @see za.co.sindi.entity.AbstractIdentifiableAuditableEntity#getCreatedBy()
 */
@Override
public User getCreatedBy() {
    // TODO Auto-generated method stub
    return createdBy;
}

/* (non-Javadoc)
 * @see za.co.sindi.entity.AbstractIdentifiableAuditableEntity#setCreatedBy(java.lang.Object)
 */
    @Override
    public void setCreatedBy(User createdBy) {
        // TODO Auto-generated method stub
        this.createdBy = createdBy;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1"
    xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
    <persistence-unit name="myapp-persistence-unit" transaction-type="JTA">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider><!-- used since Hibernate 4.3.x instead of org.hibernate.ejb.HibernatePersistence -->
        <jta-data-source>java:/jdbc/MyAppXADS</jta-data-source>
        <shared-cache-mode>ENABLE_SELECTIVE</shared-cache-mode><!-- This is the default anyway. -->
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect"/>
            <property name="hibernate.hbm2ddl.auto" value="validate" /><!-- DBA's are paid to create DB tables so never do update | create | create-drop. -->
            <property name="hibernate.cache.use_second_level_cache" value="true" />
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.enable_lazy_load_no_trans" value="true"/>
        </properties>
    </persistence-unit> 
</persistence>

问题在于将属性

createdBy

映射到

createdBy

列时。将其部署到RedHat Wildfly 8.2.0 Final时，它会运行到一个无限循环（StackOverflow错误）。我如何正确地映射它，使关系可以是一对一的，而不会让JPA发疯

我不知道为什么这是相关的，但我的

persistence.xml

如下所示：

/**
 * @author Buhake Sindi
 *
 */
@Entity
@Table(name="USER")
@Access(AccessType.FIELD)
public class User implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1600376007707987934L;

    @Id
    @Column(name="USER_NAME", nullable=false)
    private String id;

    @Column(name="FIRST_NAME", nullable=false)
    private String firstName;

    @Column(name="SECOND_NAME", nullable=false)
    private String secondName;

    @Column(name="SURNAME", nullable=false)
    private String surname;

    @Temporal(TemporalType.DATE)
    @Column(name="BIRTH_DATE", nullable=false)
    private Date birthDate;

    @Column(name="BIRTH_GENDER", columnDefinition="ENUM('M', 'F')", nullable=false)
    @Enumerated(EnumType.STRING)
    private Gender birthGender;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name="CREATION_TIMESTAMP", insertable=false, updatable=false, nullable=false)
    private Date creationTimestamp;

    @OneToOne(fetch=FetchType.LAZY)
    @JoinColumn(name="CREATED_BY", insertable=true, updatable=false, nullable=false)
    private User createdBy;

    /* (non-Javadoc)
     * @see za.co.sindi.entity.IDBasedEntity#getId()
     */
    public String getId() {
        // TODO Auto-generated method stub
        return id;
    }

    /* (non-Javadoc)
     * @see za.co.sindi.entity.IDBasedEntity#setId(java.io.Serializable)
     */
    public void setId(String id) {
        // TODO Auto-generated method stub
        this.id = id;
    }

    /**
     * @return the firstName
     */
    public String getFirstName() {
        return firstName;
    }

    /**
     * @param firstName the firstName to set
     */
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    /**
     * @return the secondName
     */
    public String getSecondName() {
        return secondName;
    }

    /**
     * @param secondName the secondName to set
     */
    public void setSecondName(String secondName) {
        this.secondName = secondName;
    }

    /**
     * @return the surname
     */
    public String getSurname() {
        return surname;
    }

    /**
     * @param surname the surname to set
     */
    public void setSurname(String surname) {
        this.surname = surname;
    }

    /**
     * @return the birthDate
     */
    public Date getBirthDate() {
        return birthDate;
    }

    /**
     * @param birthDate the birthDate to set
     */
    public void setBirthDate(Date birthDate) {
        this.birthDate = birthDate;
    }

    /**
     * @return the birthGender
     */
    public Gender getBirthGender() {
        return birthGender;
    }

    /**
     * @param birthGender the birthGender to set
     */
    public void setBirthGender(Gender birthGender) {
        this.birthGender = birthGender;
    }


    /* (non-Javadoc)
     * @see za.co.sindi.entity.AbstractIdentifiableAuditableEntity#getCreationTimestamp()
 */
    @Override
    public Date getCreationTimestamp() {
    // TODO Auto-generated method stub
    return creationTimestamp;
}

/* (non-Javadoc)
 * @see za.co.sindi.entity.AbstractIdentifiableAuditableEntity#setCreationTimestamp(java.util.Date)
 */
@Override
public void setCreationTimestamp(Date creationTimestamp) {
    // TODO Auto-generated method stub
    this.creationTimestamp = creationTimestamp;
}

/* (non-Javadoc)
 * @see za.co.sindi.entity.AbstractIdentifiableAuditableEntity#getCreatedBy()
 */
@Override
public User getCreatedBy() {
    // TODO Auto-generated method stub
    return createdBy;
}

/* (non-Javadoc)
 * @see za.co.sindi.entity.AbstractIdentifiableAuditableEntity#setCreatedBy(java.lang.Object)
 */
    @Override
    public void setCreatedBy(User createdBy) {
        // TODO Auto-generated method stub
        this.createdBy = createdBy;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1"
    xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
    <persistence-unit name="myapp-persistence-unit" transaction-type="JTA">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider><!-- used since Hibernate 4.3.x instead of org.hibernate.ejb.HibernatePersistence -->
        <jta-data-source>java:/jdbc/MyAppXADS</jta-data-source>
        <shared-cache-mode>ENABLE_SELECTIVE</shared-cache-mode><!-- This is the default anyway. -->
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect"/>
            <property name="hibernate.hbm2ddl.auto" value="validate" /><!-- DBA's are paid to create DB tables so never do update | create | create-drop. -->
            <property name="hibernate.cache.use_second_level_cache" value="true" />
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.enable_lazy_load_no_trans" value="true"/>
        </properties>
    </persistence-unit> 
</persistence>


org.hibernate.jpa.HibernatePersistenceProvider
java:/jdbc/MyAppXADS
启用\u选择性

映射看起来很好，因此我假设这一定是导致问题的实际数据库状态

您声明由创建的

为非空
；那么，如何在空的user
表中插入第一个用户呢？解决这个问题的唯一方法是指出第一个用户实际上是自己创建的
如果是这样的话（或者你有自引用用户出于任何其他原因，例如，如果你保存的用户是注册自己的，并且不是由其他用户创建的），那么无限递归的可能性很大。例如，检查您的toString
、equals
和hashCode
（我在您发布的User
类中没有看到它们，可能您为了简洁而省略了它们）
我希望Hibernate能够处理这种情况，但它可能会尝试在同一个用户
实例中反复解析createdBy
关联
不管是什么原因，错误的堆栈跟踪应该给出无限递归起源的提示
此外，您可能希望为org.hibernate
包启用跟踪
日志级别，以查看到底发生了什么。
此问题的实际问题是用户
实体是@MappedSuperclass
AbstractSoftDeleteAuditableEntity
的子类（它是泛型的）。在MappedSuperclass
实体中，将createdBy
、lastedby
和deletedBy
属性分配给绑定类型User
。在部署应用程序时，Hibernate循环尝试验证用户
实体，并导致出现堆栈溢出错误
。我将用户
实体设置为一个简单的实体，现在所有实体都已部署并验证，没有错误。
您可以添加您的持久性吗。xmlI正在使用JPA 2.1持久性框架，为什么需要我的持久性.xml
？我使用了您的sql和实体定义，它工作正常，我想查看配置，只是在我的环境中进行模拟看看我更新的帖子。我没有发现任何问题，我投了赞成票，我希望另一个开发人员能帮助解决这个问题的唯一方法是指出第一个用户实际上是自己创建的。
。答对 了这是你创造自我的唯一途径。我将发布发生的实际问题以及我是如何解决的。