EntityExistsException：具有相同标识符值的不同对象

Question

以前我没有得到任何错误,但突然我开始得到错误：

javax.persistence.EntityExistsException: A different object with the same identifier value was already associated with the session : [baag.betl.dbimporter.esmatrans.db.EquSecurityReferenceData#baag.db.SECU@59c70ceb]
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:116) ~[hibernate-core-5.2.10.Final.jar:5.2.10.Final]
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:155) ~[hibernate-core-5.2.10.Final.jar:5.2.10.Final]
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:162) ~[hibernate-core-5.2.10.Final.jar:5.2.10.Final]
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:787) ~[hibernate-core-5.2.10.Final.jar:5.2.10.Final]
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:765) ~[hibernate-core-5.2.10.Final.jar:5.2.10.Final]

if (secuData != null) {
                sessionFactory.getCurrentSession().persist(secuData);
}

i++;
    if (i % 1000 == 0) {
                sessionFactory.getCurrentSession().flush();
                sessionFactory.getCurrentSession().clear();
    }

Answer 1

要拥有复合主键，可以使用@idclass或@embeddable键方法。

要继续使用@idclass方法,您需要遵循一些规则,

• 复合主键类必须是公共的
• 它必须具有无参数构造函数
• 它必须定义equals（）和hashCode（）方法
• 它必须是可序列化的

所以在你的例子中，这个类看起来像是，

@Entity
@Table( name = "SECU" )
@IdClass( SECU.class )
public class SECU implements Serializable
{

    @Id
    @Column(name = "columnName") // use the correct column name if it varies from the variable name provided
    protected String esn;

    @Id
    @Column(name = "columnName") // use the correct column name if it varies from the variable name provided
    protected BigDecimal techrcrdid;

    @Column(name = "columnName") // use the correct column name if it varies from the variable name provided
    protected BigDecimal preTradLrgInScaleThrshld;

    @Column(name = "columnName") // use the correct column name if it varies from the variable name provided
    @Temporal( TemporalType.TIMESTAMP)
    protected LocalDateTime CreDt;

    @Column(name = "columnName") // use the correct column name if it varies from the variable name provided
    protected String fullnm;

    @Override
    public boolean equals( Object o )
    {
        if( this == o ) return true;
        if( !( o instanceof SECU ) ) return false;
        SECU secu = ( SECU ) o;
        return Objects.equals( esn, secu.esn ) &&
                       Objects.equals( techrcrdid, secu.techrcrdid ) &&
                       Objects.equals( preTradLrgInScaleThrshld, secu.preTradLrgInScaleThrshld ) &&
                       Objects.equals( CreDt, secu.CreDt ) &&
                       Objects.equals( fullnm, secu.fullnm );
    }

    @Override
    public int hashCode()
    {
        return Objects.hash( esn, techrcrdid, preTradLrgInScaleThrshld, CreDt, fullnm );
    }

    // getters and setters 
}

另外，仔细检查每个实体类中的getter和setter，问题中提供的一次似乎不正确。