如何解决JPA 转换器对“convertToDatabaseColumn”的不必要调用导致 ClassCastException
我有一个 Converter
将存储在数据库中的 String
转换为相应的 Enum
元素:
@Converter(autoApply=true)
public class DokumentTypConverter implements AttributeConverter<DokumentTypSchluessel,String> {
@Override
public String convertToDatabaseColumn(DokumentTypSchluessel attribute) {
return attribute.getValue();
}
@Override
public DokumentTypSchluessel convertToEntityAttribute(String dbData) {
return DokumentTypSchluessel.from(dbData);
}
}
我有一个实体类,它有一个枚举类型的字段:
@Entity
@Table(name="REF_DOKUMENTTYPEN")
public class DokumentTyp {
private DokumentTypSchluessel schluessel;
// snip
}
现在,当我尝试从数据库中检索该实体的实例时
String query = "SELECT d FROM DokumentTyp d WHERE d.schluessel = " + VORBEREITUNG;
entityManager.createQuery(query,DokumentTyp.class).getSingleResult();
我收到以下错误:
javax.persistence.PersistenceException: An exception occurred while calling convertToDatabaseColumn on converter class de.drvbund.pub.model.convert.DokumentTypConverter with value VORBEREITUNG
at org.eclipse.persistence.mappings.converters.ConverterClass.convertObjectValueToDataValue(ConverterClass.java:139)
at org.eclipse.persistence.mappings.foundation.AbstractDirectMapping.getFieldValue(AbstractDirectMapping.java:778)
at org.eclipse.persistence.internal.expressions.QueryKeyExpression.getFieldValue(QueryKeyExpression.java:420)
at org.eclipse.persistence.internal.expressions.ConstantExpression.printSQL(ConstantExpression.java:152)
at org.eclipse.persistence.expressions.ExpressionOperator.printDuo(ExpressionOperator.java:2241)
at org.eclipse.persistence.internal.expressions.CompoundExpression.printSQL(CompoundExpression.java:286)
at org.eclipse.persistence.internal.expressions.RelationExpression.printSQL(RelationExpression.java:899)
at org.eclipse.persistence.internal.expressions.ExpressionSQLPrinter.translateExpression(ExpressionSQLPrinter.java:325)
at org.eclipse.persistence.internal.expressions.ExpressionSQLPrinter.printExpression(ExpressionSQLPrinter.java:129)
at org.eclipse.persistence.internal.expressions.SQLSelectStatement.printSQL(SQLSelectStatement.java:1755)
at org.eclipse.persistence.internal.databaseaccess.DatabasePlatform.printSQLSelectStatement(DatabasePlatform.java:3268)
at org.eclipse.persistence.platform.database.OraclePlatform.printSQLSelectStatement(OraclePlatform.java:967)
at org.eclipse.persistence.internal.expressions.SQLSelectStatement.buildCall(SQLSelectStatement.java:843)
at org.eclipse.persistence.internal.expressions.SQLSelectStatement.buildCall(SQLSelectStatement.java:854)
at org.eclipse.persistence.descriptors.ClassDescriptor.buildCallFromStatement(ClassDescriptor.java:815)
at org.eclipse.persistence.internal.queries.StatementQueryMechanism.setCallFromStatement(StatementQueryMechanism.java:390)
at org.eclipse.persistence.internal.queries.StatementQueryMechanism.prepareSelectAllRows(StatementQueryMechanism.java:315)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.prepareSelectAllRows(ExpressionQueryMechanism.java:1723)
at org.eclipse.persistence.queries.ReadAllQuery.prepareSelectAllRows(ReadAllQuery.java:904)
at org.eclipse.persistence.queries.ReadAllQuery.prepare(ReadAllQuery.java:835)
at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:673)
... 151 more
Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to de.drvbund.pub.enums.DokumentTypSchluessel
我猜框架从查询中获取 toString()
元素的 Enum
表示,假设它是实体属性值,需要转换为其相应的 dbValue 并尝试调用convertToDatabaseColumn()
方法传递 String
。我只是不知道如何正确地做到这一点。
如何使用 JPA 检索由 Enum
属性值过滤的实体?
解决方法
问题在克里斯的建议下得到解决:
entityManager.createQuery("SELECT d FROM DokumentTyp d WHERE d.schluessel = ?1",DokumentTyp.class)
.setParameter(1,DokumentTypSchluessel.VORBEREITUNG)
.getSingleResult();
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。