hibernate,hql与sql的缓存使用 setResultTransformer的用法

hibernate,hql与sql的缓存使用   http://blog.csdn.net/diquren/article/details/23695293
getSessionFactory().evictQueries(); //清除缓存

1.在hibernate中createQuery执行hql查询的时候使用查询缓存：

 

    getSession().createQuery(hql).setCacheable(true).setCacheRegion("user").list();

2.在hibernate中createSQLQuery执行sql时使用查询缓存：

 

    getSession().createSQLQuery(sql).setResultTransformer(Transformers.aliasToBean(User.class)).setCacheable(true).setCacheRegion("user").list();

这样会报错，原因是That's because the aim of the second level cache is to (ultimately) cache entities that Hib knows about. I haven't verified this but I'm not surprised that caching sql query doesn't work as those are not (directly) translated by hibernate into entities.

解决方法：

It's solutioned adding column's types to the query, using the method "addScalar()"

like this：

 

    getSession().createSQLQuery(sql).addScalar("id", IntegerType.INSTANCE)

    .addScalar("name",StringType.INSTANCE)

    .addScalar("age",IntegerType.INSTANCE).setResultTransformer(Transformers.aliasToBean(User.class))

    .setCacheable(true).setCacheRegion("user").list();

转自：http://www.360doc.com/content/14/0331/13/16589843_365170644.shtml

setResultTransformer的用法 http://blog.csdn.net/sinat_24928447/article/details/47746397
用于将数据库查询到的数据打包成临时的包装类，结合EL表达式来展示，例如报表什么的。

基本就分两种，写法如下：

hql：Query query = session.createQuery("select id , account , password  from User")

.setResultTransformer(new AliasToBeanResultTransformer(U.class))

sql：Query query = session.createSQLQuery("select CN_ID as id ,CN_ACCOUNT as account  ,CN_PASSWORD as password from TN_USER")

                .addScalar("id", Hibernate.INTEGER)

                .addScalar("account",Hibernate.STRING)

                .addScalar("password",Hibernate.STRING)

                .setResultTransformer(Transformers.aliasToBean(U.class));