Spring with Query Dsl custom binding and or operation doesn't work

QuerydslBindings.TypeBinder#first uses a single value binding. You need to use QuerydslBindings.TypeBinder#all. This method operates on a multivalue binding.

I provided several examples of how to customize your bindings in this answer. Something like this should work for you:

@Overridedefault public void customize(QuerydslBindings bindings, QArticle article) {    // using explicit path bindings    bindings.bind(article.category).all((path, values) -> {        BooleanBuilder predicate = new BooleanBuilder();        // with a for loop        for (String value : values) {            predicate.or(path.containsIgnoreCase(value));        }    });    // using a type binding    bindings.bind(String.class).all((StringPath path, Collection<? extends String> values) -> {        BooleanBuilder predicate = new BooleanBuilder();        // oneliner with Java 8 forEach        values.forEach( value -> predicate.or(path.containsIgnoreCase(value) );    });}

The correct bindings for your article.category property should be like this:

bindings.bind(article.category).all((path, value) -> {    BooleanBuilder predicate = new BooleanBuilder();    value.forEach(o -> predicate.or(path.equalsIgnoreCase(o)));    return Optional.of(predicate);});

If you don't need any manipulations of the parameters (like ignoring case) you can simplify it to that:

bindings.bind(article.category).all((path, value) -> Optional.of(path.in(value)));

After a good search on it I found the solution.

 bindings.bind(String.class).all(new MultiValueBinding<StringPath, String> () {        @Override        public Predicate bind(StringPath path, Collection<? extends String> values) {            BooleanBuilder predicate = new BooleanBuilder();            values.forEach( value -> predicate.or(path.containsIgnoreCase(value)));            return predicate;        }    });