如何在 Hibernate 搜索查询中使用 QueryDSL BooleanExpression？

Question

I have a complex, reusable method that returns a BooleanExpression to filter a Q object QPost .

How do I use this BooleanExpression in a Hibernate Search query like this:

Search.session(entityManager).search(Post.class)
                .where(f -> {
                    var boolStep = f.bool()
                            .must(f.match().fields("title", "text", "author.name").matching(searchText))
});

Answer 1

You mean an expression built using the QueryDSL project ?

That project still uses Hibernate Search 5 , not 6, so currently you cannot use it with Hibernate Search 6.

Perhaps you should create an issue on that project, and if you can, contribute the upgrade yourself?

Answer 2

To use the BooleanExpression in the Hibernate Search query, you can pass it as an argument to the must or mustNot methods of the BoolFieldContext object.

Here's an example of how you can do this:

Search.session(entityManager).search(Post.class)
            .where(f -> {
                var boolStep = f.bool()
                        .must(booleanExpression)
                        .must(f.match().fields("title", "text", "author.name").matching(searchText))

}); In this example, the booleanExpression is a BooleanExpression that you want to use to filter the query results. The must method adds a "must" clause to the Boolean query, meaning that the documents returned by the query must match the clause. If you want to exclude documents that match the BooleanExpression, you can use the mustNot method instead.

You can also combine multiple BooleanExpressions using the should method, which adds a "should" clause to the Boolean query. This means that the documents returned by the query may or may not match the clause, depending on the minimum number of "should" clauses that must match as specified by the minimumShouldMatch method.

For example:

Copy code

Search.session(entityManager).search(Post.class)
                .where(f -> {
                    var boolStep = f.bool()
                            .must(booleanExpression1)
                            .should(booleanExpression2)
                            .mustNot(booleanExpression3)
                            .minimumShouldMatch(1)
                            .must(f.match().fields("title", "text", "author.name").matching(searchText))
});

In this example, the query will return documents that match booleanExpression1 and booleanExpression3, and may also match booleanExpression2, as long as at least one of the "should" clauses matches.