将原生SQL功能Hibernate到您的Spring Data Repository中

JPA为您提供@NamedNativeQuery以便使用本机SQL。但是，用法并不方便，特别是当您需要在本机SQL中映射多个实体时。您必须定义一组SqlResultSetMapping映射，这很容易出错。

对于以前使用过Hibernate本机SQL功能的用户，您会发现它比JPA的@NamedNativeQuery更易于使用。在最近的项目中，我正在使用Spring Data JPA。我已将Hibernate的本机查询功能添加到我的Spring数据库中。现在，您可以在JPA中执行本机查询，而无需使用SqlResultSetMapping。

1.添加您的客户注解@NativeQueries和@NativeQuery

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface NativeQueries {NativeQuery[] queries() default  {};
}

@Retention(RetentionPolicy.RUNTIME)
public @interface NativeQuery {String name()  default "";String sql()  default "";
}

2.在基础Spring Data Repository中添加“ queryNatively”方法。

如果您不知道如何向Spring数据JPA基础存储库添加自定义行为，请参阅我以前的文章，了解如何自定义Spring数据JPA基础存储库。您可以在上一篇文章中看到，我有意在GenericRepositoryImpl中公开存储库接口（即springDataRepositoryInterface属性）。这些小技巧使我能够轻松访问存储库界面中的注释。

public List queryNatively(String nativeQueryName, LinkedHashMap<String,Class<?>> inEntityClasses, Map inParams ){SQLQuery query =  this.createHibernateNativeQuery( nativeQueryName,  inParams );//add entitiesif (inEntityClasses!=null) {      for (Object key: inEntityClasses.keySet()) {String entityClassAlias = key.toString();Class<?> entityClass = (Class<?>)inEntityClasses.get(key);  query.addEntity(entityClassAlias,entityClass);}    }//add parameterif (inParams != null){for (Object key: inParams.keySet()) {String queryParamName = key.toString();Object queryParamValue = inParams.get(key);query.setParameter(queryParamName, queryParamValue);}}  return (query!=null)? query.list() : null ;}private SQLQuery createHibernateNativeQuery (String nativeQueryName, Map inParams ){if (GenericRepository.class.isAssignableFrom(getSpringDataRepositoryInterface())) {Annotation nativeQueryAnn = getSpringDataRepositoryInterface().getAnnotation(NativeQueries.class);if(nativeQueryAnn != null){NativeQueries nativeQueries = (NativeQueries)nativeQueryAnn;NativeQuery[] queries  = nativeQueries.queries();for (NativeQuery sqlquery : queries) { if (StringUtils.equals(nativeQueryName, sqlquery.name())) {String sql  = sqlquery.sql();Session hiernateSess = em.unwrap(Session.class);SQLQuery query = hiernateSess.createSQLQuery(sql);//add parameterif (inParams != null){for (Object key: inParams.keySet()) {String queryParamName = key.toString();Object queryParamValue = inParams.get(key);query.setParameter(queryParamName, queryParamValue);}}  return query;}    }}}return null;}

3.示例用法

在存储库界面中，通过@NativeQueries和@NativeQuery批注定义要使用的本机SQL查询。用法与调用Hibernate本机查询功能相似。您可能只看到Hibernate别名和属性引用。

@NativeQueries (queries = {@NativeQuery(name="query1", sql="SELECT {cat.*}, {mother.*}  FROM CATS c, CATS m WHERE c.MOTHER_ID = c.ID and c.name =  :catName "),@NativeQuery(name="query2", sql="SELECT {cat.*} FROM CATS where c.ID =  :catName")       }
)
public interface CatRepository extends GenericRepository<Cat, Long> {
}

在注入存储库的服务或业务类中，您只需简单地调用queryNatively（）方法即可执行本机SQL查询。

@Service
public class CatService {@Injectprivate CatRepository catRepository;public List<Cat> searchCat( String catName) {List<Cat> catList;// Add entity mapping for your queryHashMap<String, Object> inParams = new HashMap<String, Object>();inParams.put("catName", "Felix");// Prepare parameters for your native sqlLinkedHashMap<String, Object> entityMap = new LinkedHashMap<String, Object>();entityMap.put("cat", Cat.class);entityMap.put("mother",Mother.class);catList = catRepository.queryNatively("query1", "",entityParam);return catList;}
}

参考：来自Programming Peacely博客的JCG合作伙伴 Boris Lam 向您的Spring Data Repository中添加了Hibernate本机SQL功能。