如何用Hibernate实现一个自定义的String序列标识符生成器 [英] How to implement a custom String sequence identifier generator with Hibernate

问题描述

我在spring中使用hibernate，h2和liquibase，我试图通过以博文但是我得到一个错误：引起：org.hibernate.id.IdentifierGenerationException：ids的未知整数数据类型：java.lang.String

这里是我的SequenceStyleGenerator代码：

  public class CTCIDGenerator extends SequenceStyleGenerator {
 
 @Override 
 public Serializable generate（SessionImplementor session，Object obj）{
 if（obj instanceof Identifiable）{
 Identifiable identifiable =（Identifiable）obj; 
 Serializable id = identifiable.getId（）; 
 if（id！= null）{
 return id; 
} 
} 
返回CTC+ super.generate（session，obj）; 
 
 
 $ / code> 

我的实体代码：



  @Entity 
 @Table（name =contact）
 public class Contact实现Serializable，Identifiable< String> {
 
 private static final long serialVersionUID = 1L; 
 
 @Id 
 @GenericGenerator（
 name =assigned-sequence，
 strategy =net.atos.seirich.support.domain.idgenerator.CTCIDGenerator ，
 parameters = @ org.hibernate.annotations.Parameter（
 name =sequence_name，
 value =hibernate_sequence
）
）
 @ GeneratedValue（generator =assigned-sequence，strategy = GenerationType.SEQUENCE）
 private String id; 
 
 public String getId（）{
 return id; 
} 
 
 public void setId（String id）{
 this.id = id; 
 
 
  





和liquibase XML：

 <？xml version =1.0encoding =utf-8？> 
< databaseChangeLog 
 xmlns =http://www.liquibase.org/xml/ns/dbchangelog
 xmlns：xsi =http://www.w3.org/2001 / XMLSchema-instance
 xsi：schemaLocation =http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.4.xsd > 
 
  
   
< changeSet id =20160513091901-1author =jhipster> 
< createTable tableName =contact> 
< column name =idtype =longvarcharautoIncrement =$ {autoIncrement}> 
< constraints primaryKey =truenullable =false/> 
< / column> 
< / changeSet> 
< / databaseChangeLog> 
  

顺便说一句，有可能避免参数sequence_name，因此hibernate可以自己处理这个参数吗？

如果有人可以帮助我，谢谢！

解决方案

问题在于 SequenceStyleGenerator 期望返回一个数值，而不是 String 。

我已经尝试 a这个问题的解决方案，它像一个魅力。因此，您需要更改您的生成器，如下所示：

  public class StringSequenceIdentifier implements IdentifierGenerator，Configurable {
 
 private String sequenceCallSyntax; 
 $ b @Override 
 public void configure（Type params，ServiceRegistry serviceRegistry）throws MappingException {
 final JdbcEnvironment jdbcEnvironment = serviceRegistry.getService（JdbcEnvironment.class）; 
 final方言dialect = jdbcEnvironment.getDialect（）; 
 
 final String sequencePerEntitySuffix = ConfigurationHelper.getString（CONFIG_SEQUENCE_PER_ENTITY_SUFFIX，params，DEF_SEQUENCE_SUFFIX）; 
 
 final String defaultSequenceName = ConfigurationHelper.getBoolean（CONFIG_PREFER_SEQUENCE_PER_ENTITY，params，false）
？ params.getProperty（JPA_ENTITY_NAME）+ sequencePerEntitySuffix 
：DEF_SEQUENCE_NAME; 
 
 sequenceCallSyntax = dialect.getSequenceNextValString（ConfigurationHelper.getString（SEQUENCE_PARAM，params，defaultSequenceName））; 
 
 $ b @Override 
 public Serializable generate（SessionImplementor session，Object obj）{
 if（obj instanceof Identifiable）{
 Identifiable identifiable =（Identifiable ）obj; 
 Serializable id = identifiable.getId（）; 
 if（id！= null）{
 return id; 
 
 
 long seqValue =（（Number）Session.class.cast（session）
 .createSQLQuery（sequenceCallSyntax）
 .uniqueResult（））。longValue ）; 
 
返回CTC+ seqValue; 
 
 
 $ / code $ / pre 
 $ b $ p您的映射变为：
 
 
  @Entity（name =Post）
 @Table（name =post）
 public static class Post implements Identifiable<串GT; {
 
 @Id 
 @GenericGenerator（
 name =assigned-sequence，
 strategy =com.vladmihalcea.book.hpjp.hibernate.identifier.StringSequenceIdentifier ，
 parameters = @ org.hibernate.annotations.Parameter（name =sequence_name，value =hibernate_sequence）
）
 @GeneratedValue（generator =assigned-sequence，strategy = GenerationType.SEQUENCE）
私人字符串ID; 
 
 @版本
私人整数版本; 
 $ b $ public Post（）{
} 
 
 public Post（String id）{
 this.id = id; 
} 
 
 @Override 
 public String getId（）{
 return id; 
 
 
  
现在，当您插入以下实体时： p> 
 
 
  doInJPA（entityManager  - > {
 entityManager.persist（new Post（））; 
 entityManager.persist （new Post（ABC））; 
 entityManager.persist（new Post（））; 
 entityManager.persist（new Post（DEF））; 
}）; 
  
 Hibernate生成正确的标识符：
 Query：[select nextval（'hibernate_sequence'）]，Params：[（）] 
 Query：[select nextval（'hibernate_sequence'）]，Params：[ （）] 
 Query：[insert into post（version，id）values（？，？）]，Params：[（0，CTC1）] 
 Query：[insert into post ，id）values（？，？）]，Params：[（0，ABC）] 
 Query：[insert into post（version，id）values（？，？）]，Params：[ 0，CTC2）] 
 Query：[insert into post（version，id）values（？，？）]，Params：[（0，DEF）] 
  
  GitHub 。
 
I'm using hibernate with spring, h2 and liquibase and I'm trying to make a custom String id generator for my entities by taking example with this blog post but I'm getting an error : Caused by: org.hibernate.id.IdentifierGenerationException: Unknown integral data type for ids : java.lang.String

Here my SequenceStyleGenerator code :
public class CTCIDGenerator extends SequenceStyleGenerator {

    @Override
    public Serializable generate(SessionImplementor session, Object obj) {
        if (obj instanceof Identifiable) {
            Identifiable identifiable = (Identifiable) obj;
            Serializable id = identifiable.getId();
            if (id != null) {
                return id;
            }
        }
        return "CTC"+super.generate(session, obj);
    }
}
My entity code : 
@Entity
@Table(name = "contact")
public class Contact implements Serializable, Identifiable<String> {

    private static final long serialVersionUID = 1L;

    @Id
    @GenericGenerator(
        name = "assigned-sequence",
        strategy =     "net.atos.seirich.support.domain.idgenerator.CTCIDGenerator",
        parameters = @org.hibernate.annotations.Parameter(
            name = "sequence_name", 
            value = "hibernate_sequence"
        )
    )
    @GeneratedValue(generator = "assigned-sequence", strategy = GenerationType.SEQUENCE)
    private String id;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }
}
And the liquibase XML :
<?xml version="1.0" encoding="utf-8"?>
<databaseChangeLog
xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.4.xsd">

    <property name="autoIncrement" value="true" dbms="mysql,h2,postgresql,oracle"/>

    <property name="floatType" value="float4" dbms="postgresql, h2"/>
    <property name="floatType" value="float" dbms="mysql, oracle"/>

    <changeSet id="20160513091901-1" author="jhipster">
        <createTable tableName="contact">
            <column name="id" type="longvarchar" autoIncrement="${autoIncrement}">
                <constraints primaryKey="true" nullable="false"/>
            </column>
    </changeSet>
</databaseChangeLog>
Btw is it possible to avoid the parameter sequence_name so hibernate can handle this by itself ?

If anyone can help me, Thanks !
解决方案
The problem is that SequenceStyleGenerator expects to return a numerical value, not a String.

I already tried a solution for this problem and it works like a charm. Therefore, you need to change your generator like this:
public class StringSequenceIdentifier implements IdentifierGenerator, Configurable {

    private String sequenceCallSyntax;

    @Override
    public void configure(Type type, Properties params, ServiceRegistry serviceRegistry) throws MappingException {
        final JdbcEnvironment jdbcEnvironment = serviceRegistry.getService(JdbcEnvironment.class);
        final Dialect dialect = jdbcEnvironment.getDialect();

        final String sequencePerEntitySuffix = ConfigurationHelper.getString(CONFIG_SEQUENCE_PER_ENTITY_SUFFIX, params, DEF_SEQUENCE_SUFFIX);

        final String defaultSequenceName = ConfigurationHelper.getBoolean(CONFIG_PREFER_SEQUENCE_PER_ENTITY, params, false)
                ? params.getProperty(JPA_ENTITY_NAME) + sequencePerEntitySuffix
                : DEF_SEQUENCE_NAME;

        sequenceCallSyntax = dialect.getSequenceNextValString(ConfigurationHelper.getString(SEQUENCE_PARAM, params, defaultSequenceName));
    }

    @Override
    public Serializable generate(SessionImplementor session, Object obj) {
        if (obj instanceof Identifiable) {
            Identifiable identifiable = (Identifiable) obj;
            Serializable id = identifiable.getId();
            if (id != null) {
                return id;
            }
        }
        long seqValue = ((Number) Session.class.cast(session)
            .createSQLQuery(sequenceCallSyntax)
            .uniqueResult()).longValue();

        return "CTC" + seqValue;
    }
}
Your mapping becomes:
@Entity(name = "Post")
@Table(name = "post")
public static class Post implements Identifiable<String> {

    @Id
    @GenericGenerator(
        name = "assigned-sequence",
        strategy = "com.vladmihalcea.book.hpjp.hibernate.identifier.StringSequenceIdentifier",
        parameters = @org.hibernate.annotations.Parameter(name = "sequence_name", value = "hibernate_sequence")
    )
    @GeneratedValue(generator = "assigned-sequence", strategy = GenerationType.SEQUENCE)
    private String id;

    @Version
    private Integer version;

    public Post() {
    }

    public Post(String id) {
        this.id = id;
    }

    @Override
    public String getId() {
        return id;
    }
}
Now, when you insert the following entities:
doInJPA(entityManager -> {
    entityManager.persist(new Post());
    entityManager.persist(new Post("ABC"));
    entityManager.persist(new Post());
    entityManager.persist(new Post("DEF"));
});
Hibernate generates the right identifier:
Query:["select nextval ('hibernate_sequence')"], Params:[()]
Query:["select nextval ('hibernate_sequence')"], Params:[()]
Query:["insert into post (version, id) values (?, ?)"], Params:[(0, CTC1)]
Query:["insert into post (version, id) values (?, ?)"], Params:[(0, ABC)]
Query:["insert into post (version, id) values (?, ?)"], Params:[(0, CTC2)]
Query:["insert into post (version, id) values (?, ?)"], Params:[(0, DEF)]
Code available on GitHub.

                        
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