Enum 字段类型的 Hibernate SQL 转换失败 [英] Hibernate SQL transformation fails for Enum field type

问题描述

我正在使用 SQL 查询，然后使用 Hibernates 的 Transformers.aliasToBean() 转换结果.我的查询中的一列是枚举.枚举的转换以某种方式失败.我该怎么办?我应该使用哪种数据类型?我想要超过 1 个字符将结果转换为我的枚举类型.

I am using a SQL query and then transforming the result using Hibernates's Transformers.aliasToBean(). One of the columns in my query is an enum. The transformation somehow fails for the enum. What should I do? Which datatype should I use? I want more than 1 character to transform the result into my enum type.

这是我的查询/代码的简化版本的样子(b 是表配置文件中的枚举):

This is how the simplified version of my query/code looks like (b is an enum in the table profiles):

session.createSQLQuery("select a, b from profiles").setResultTransformer(Transformers.aliasToBean(Profile.class))
                    .list();

异常:预期类型:Foo.ProfileStateEnum，实际值:java.lang.Character

推荐答案

假设 b 列对应的 java 枚举类型是 Foo.ProfileStateEnum，下面的代码片段应该适合你.(我用 Hibernate 4.1.6 测试过)

Assuming that the java enum type that corresponds to column b is Foo.ProfileStateEnum, the following code snippet should work for you. (I tested with Hibernate 4.1.6)

import java.util.Properties;
import org.hibernate.type.Type;
import org.hibernate.type.IntegerType;
import org.hibernate.internal.TypeLocatorImpl.TypeLocatorImpl;
import org.hibernate.type.TypeResolver.TypeResolver;
import org.hibernate.type.EnumType;

Properties params = new Properties();
params.put("enumClass", "Foo.ProfileStateEnum");
params.put("type", "12"); /*type 12 instructs to use the String representation of enum value*/
/*If you are using Hibernate 5.x then try:
params.put("useNamed", true);*/
Type myEnumType = new TypeLocatorImpl(new TypeResolver()).custom(EnumType.class, params);

List<Profile> profileList= getSession().createSQLQuery("select a as ID, b from profiles")
            .addScalar("ID", IntegerType.INSTANCE)
            .addScalar("b", myEnumType )
            .setResultTransformer(Transformers.aliasToBean(Profile.class))
            .list();

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