java - JPA/Criteria 类似百分比字符

Question

我正在尝试构建动态查询(具有类似条件)。当我在 mysql 中尝试使用原始 sql 时，效果非常好。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，但无法在 Java 中获得相同的结果。只是空结果。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 + "%");
            }
        };
}

有什么问题吗？

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;
        }
    };