Hibernate搜索中的单个返回类型

Question

假设我有一个应用程序，有许多不同的实体，它们之间没有关系。

我想创建一个搜索，查询所有这些，但返回一个统一的类型，即：

class SearchResult {
  String stype;
  String title;
  String teaser;
}

@Indexed(index = "idx_search")
class Book {
  @Field(name = "stype", analyze = ...)
  final String stype = "BOOK";
  @Field(name = "title", analyze = ...)
  String bookTitle;
  @Field(name = "teaser", analyze = ...)
  String bookBlurb ;
}

@Indexed(index = "idx_search")
class Person{
  @Field(name = "stype", analyze = ...)
  final String stype = "PERSON";
  @Field(name = "title", analyze = ...)
  String fullname;
  @Field(name = "teaser", analyze = ...)
  String profileIntroText;
}

@Indexed(index = "idx_search")
class Location{
  @Field(name = "stype", analyze = ...)
  final String stype = "LOCATION";      
  @Field(name = "title", analyze = ...)
  String streetPcAndCity;
  @Field(name = "teaser", analyze = ...)
  String wikiIntoText;
}

SearchResult[stype: PERSON, title: Spongebob, teaser: A funny sponge]
SearchResult[stype: BOOK, title: Clean Architecture , teaser: A Craftsmans Guide to Software...]
SearchResult[stype: PERSON, title: Patric, teaser: A funny seastar]
SearchResult[stype: LOCATION, title: Hannover, teaser: A city in Germany]

final QueryBuilder queryBuilder = fullTextEntityManager
            .getSearchFactory()
            .buildQueryBuilder()
            .forEntity(SearchResult.class)
            .get();
...

HSearch000331:无法为既未配置也未配置任何子类型的类型“SearchResult”生成查询。

你认为有办法让它起作用吗？

Answer 1

注意，您不需要将每个类型分配给相同的索引；Hibernate Search完全能够在单个查询中搜索多个索引。性能可能是相同的（无论如何，Lucene索引通常被分成多个区段）。

话虽如此，假设SearchResult中有一个构造函数，下面是如何实现的：

class SearchResult {
  String stype;
  String title;
  String teaser;

  public SearchResult(String stype, String title, String teaser) {
    this.stype = stype;
    this.title = title;
    this.teaser = teaser;
  }
}

FullTextEntityManager fullTextEntityManager = Search.getFullTextEntityManager( entityManager);
final QueryBuilder queryBuilder = fullTextEntityManager
            .getSearchFactory()
            .buildQueryBuilder()
            .forEntity(Book.class)
            .get();

Query luceneQuery = ...;

FullTextQuery query = fullTextEntityManager.createFullTextQuery(query, Book.class, Person.class, Location.class);
query.setProjection("stype", "title", "teaser");
query.setMaxResults(20);

List<Object[]> arrayResults = query.list();

List<SearchResult> hits = new ArrayList<>();
for (Object[] array : arrayResults) {
    hits.add(new SearchResult((String) array[0], (String) array[1], (String) array[2]);
}

还要注意，如果升级到Hibernate Search6，这可能会明显减少尴尬。

@Indexed
class Book {
  @KeywordField(name = "stype")
  @IndexingDependency(reindexOnUpdate = ReindexOnUpdate.NO)
  final String stype = "BOOK";
  @FullTextField(name = "title", analyzer = ...)
  String bookTitle;
  @FullTextField(name = "teaser", analyzer = ...)
  String bookBlurb ;
}

@Indexed
class Person{
  @KeywordField(name = "stype")
  @IndexingDependency(reindexOnUpdate = ReindexOnUpdate.NO)
  final String stype = "PERSON";
  @FullTextField(name = "title", analyzer = ...)
  String fullname;
  @FullTextField(name = "teaser", analyzer = ...)
  String profileIntroText;
}

@Indexed
class Location{
  @KeywordField(name = "stype")
  @IndexingDependency(reindexOnUpdate = ReindexOnUpdate.NO)
  final String stype = "LOCATION";      
  @FullTextField(name = "title", analyzer = ...)
  String streetPcAndCity;
  @FullTextField(name = "teaser", analyzer = ...)
  String wikiIntoText;
}

List<SearchResult> hits = Search.session(entityManager)
        .search(Book.class, Person.class, Location.class)
        .select(f -> f.composite(
                SearchResult::new,
                f.field("stype", String.class),
                f.field("title", String.class),
                f.field("teaser", String.class)))
        .where(f -> ...)
        .fetchHits( 20 );

interface Searchable {
  @KeywordField(analyzer = ...)
  String getStype();
  @FullTextField(analyzer = ...)
  String getTitle();
  @FullTextField(analyzer = ...)
  String getTeaser();
}

@Indexed
class Book implements Searchable {
  String bookTitle;
  String bookBlurb;

  @Override
  @javax.persistence.Transient
  @IndexingDependency(reindexOnUpdate = ReindexOnUpdate.NO)
  String getStype() {
      return "BOOK";
  }
  @Override
  @javax.persistence.Transient
  @IndexingDependency(derivedFrom = @ObjectPath(
          @PropertyValue(propertyName = "bookTitle")
  ))
  String getTitle() {
      return bookTitle;
  }
  @Override
  @javax.persistence.Transient
  @IndexingDependency(derivedFrom = @ObjectPath(
          @PropertyValue(propertyName = "bookTitle")
  ))
  String getTeaser() {
      return bookBlurb;
  }
}

@Indexed
class Person implements Searchable {
  String fullname;
  String profileIntroText;

  @Override
  @javax.persistence.Transient
  @IndexingDependency(reindexOnUpdate = ReindexOnUpdate.NO)
  String getStype() {
      return "PERSON";
  }
  @Override
  @javax.persistence.Transient
  @IndexingDependency(derivedFrom = @ObjectPath(
          @PropertyValue(propertyName = "bookTitle")
  ))
  String getTitle() {
      return bookTitle;
  }
  @Override
  @javax.persistence.Transient
  @IndexingDependency(derivedFrom = @ObjectPath(
          @PropertyValue(propertyName = "bookTitle")
  ))
  String getTeaser() {
      return bookBlurb;
  }
}

@Indexed
class Location implements Searchable {
  String streetPcAndCity;
  String wikiIntoText;

  @Override
  @javax.persistence.Transient
  @IndexingDependency(reindexOnUpdate = ReindexOnUpdate.NO)
  String getStype() {
      return "LOCATION";
  }
  @Override
  @javax.persistence.Transient
  @IndexingDependency(derivedFrom = @ObjectPath(
          @PropertyValue(propertyName = "streetPcAndCity")
  ))
  String getTitle() {
      return streetPcAndCity;
  }
  @Override
  @javax.persistence.Transient
  @IndexingDependency(derivedFrom = @ObjectPath(
          @PropertyValue(propertyName = "wikiIntoText")
  ))
  String getTeaser() {
      return wikiIntoText;
  }
}

List<SearchResult> hits = Search.session(entityManager)
        .search(Searchable.class)
        .select(f -> f.composite(
                SearchResult::new,
                f.field("stype", String.class),
                f.field("title", String.class),
                f.field("teaser", String.class)))
        .where(f -> ...)
        .fetchHits( 20 );

或者，您可以直接加载实体：

List<Searchable> hits = Search.session(entityManager)
        .search(Searchable.class)
        .where(f -> ...)
        .fetchHits( 20 );

for (Searchable hit : hits) {
    String stype = hit.getStype();
    String title = hit.getTitle();
    String teaser = hit.getTeaser();
    if ( hit instanceof Book ) {
        ...
    }
    else if ( hit instanceof Location ) {
        ...
    }
    else { 
        ...
    } 
}