JPA / Criteria就像百分比字符一样

Question

我正在尝试构建动态查询（具有类似条件）。当我用原始的sql尝试它进入mysql时，它运行得很好。这是一个例子：

select * from dbiwant.want_activity m where m.want like "%bike%"

然后，我尝试使用CriteriaBuilder，但是我无法在Java中获得相同的结果。只是空的结果。这是我的代码：

Specifications specifications = Specifications.where(specificationService.isLike("want", search));


public Specification<WantActivity> isLike(String param, String search) {
        return new Specification<WantActivity>() {
            public javax.persistence.criteria.Predicate toPredicate(Root<WantActivity> root, CriteriaQuery<?> query,
                                                                    CriteriaBuilder builder) {
                return builder.like(root.get(param) ,"%" + search + "%");
            }
        };
}

有什么问题？

Answer 1

试试这个：

public Specification<WantActivity> isLike(String param, String search) {
    return new Specification<WantActivity>() {
        public javax.persistence.criteria.Predicate toPredicate(Root<WantActivity> root, CriteriaQuery<?> query,
                                                                CriteriaBuilder builder) {

final Predicate like = query.where(builder.like(root.<String> get(param), search)).getRestriction();
return like;
        }
    };