Java 字母数字字段的字符串增量用于JPA不工作
我试图为一个不是主键的字段设置此字段 这里也有相同的解决方案: 但当我运行程序时,即使它也不会转到Java方法。它保存为null 我看不到我放在课堂上的日志。我的课没有日志 我从那个博客上复制了,但我的代码是:Java 字母数字字段的字符串增量用于JPA不工作,java,spring-data-jpa,Java,Spring Data Jpa,我试图为一个不是主键的字段设置此字段 这里也有相同的解决方案: 但当我运行程序时,即使它也不会转到Java方法。它保存为null 我看不到我放在课堂上的日志。我的课没有日志 我从那个博客上复制了,但我的代码是: public class StringSequenceIdentifier implements IdentifierGenerator, Configurable { public static final String SEQUENCE_PREFIX =
public class StringSequenceIdentifier
implements IdentifierGenerator, Configurable {
public static final String SEQUENCE_PREFIX = "sequence_prefix";
private String sequencePrefix;
private String sequenceCallSyntax;
@Override
public void configure(
Type type, Properties params, ServiceRegistry serviceRegistry)
throws MappingException {
System.out.println("xxx");
final JdbcEnvironment jdbcEnvironment =
serviceRegistry.getService(JdbcEnvironment.class);
final Dialect dialect = jdbcEnvironment.getDialect();
final ConfigurationService configurationService =
serviceRegistry.getService(ConfigurationService.class);
String globalEntityIdentifierPrefix =
configurationService.getSetting( "entity.identifier.prefix", String.class, "SEQ_" );
sequencePrefix = ConfigurationHelper.getString(
SEQUENCE_PREFIX,
params,
globalEntityIdentifierPrefix);
final String sequencePerEntitySuffix = ConfigurationHelper.getString(
SequenceStyleGenerator.CONFIG_SEQUENCE_PER_ENTITY_SUFFIX,
params,
SequenceStyleGenerator.DEF_SEQUENCE_SUFFIX);
final String defaultSequenceName = ConfigurationHelper.getBoolean(
SequenceStyleGenerator.CONFIG_PREFER_SEQUENCE_PER_ENTITY,
params,
false)
? params.getProperty(JPA_ENTITY_NAME) + sequencePerEntitySuffix
: SequenceStyleGenerator.DEF_SEQUENCE_NAME;
sequenceCallSyntax = dialect.getSequenceNextValString(
ConfigurationHelper.getString(
SequenceStyleGenerator.SEQUENCE_PARAM,
params,
defaultSequenceName));
}
@Override
public Serializable generate(SharedSessionContractImplementor session, Object obj) {
System.out.println("xxx");
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 sequencePrefix + String.format("%011d%s", 0 ,seqValue);
}
}
在我的领域:
@GenericGenerator(
name = "assigned-sequence",
strategy = "xxxxxx.StringSequenceIdentifier",
parameters = {
@org.hibernate.annotations.Parameter(
name = "sequence_name", value = "hibernate_sequence"),
@org.hibernate.annotations.Parameter(
name = "sequence_prefix", value = "CTC_"),
}
)
@GeneratedValue(generator = "assigned-sequence", strategy = GenerationType.SEQUENCE)
private String referenceCode;
我想要的是
我需要一个唯一的字段,它不是主字段。所以,我决定递增是最好的解决方案,因为否则,我必须检查每个创建的随机数,如果它存在于数据库中(我还为此打开了建议)
大约5-6个字符和字母数字
我想让JPA增加这个,但似乎我做不到。这与非常相似,但我不认为它是完全重复的。然而,答案似乎是适用的,它们似乎提出了以下策略:
@PrePersist
在字段持久化之前填充该字段@Generated
并使用触发器或类似工具在数据库中生成值步骤3建议从2008年开始使用xml和xml。还有其他方法吗?在对该答案的评论中,
@Generated
作为基于注释的等价物给出。但无法理解3。解决方案我怎样才能添加前缀呢