2

这是获取由参数生成的标签列表并从控制器传递到服务的代码。我正在尝试将餐馆列表过滤为仅包含具有匹配标签属性的餐馆。我是编程和 grails 的新手，所以请原谅任何愚蠢的错误：

    class Eatery {
        String name
        String phone
        Date lastVisited
        List<Tag> tags
        static hasOne = [location: Location]
        static hasMany = [tags: Tag];
        static constraints = {
            name nullable: false, blank: false
            phone nullable: true, blank: true
            location nullable: true, blank: true
            tags nullable: true, blank: true
            lastVisited nullable: true, blank: true
        }
        public String toString() {
            return name
        }
}

下面是服务方法：

Eatery getRandomEatery(List<Tag> tagList) {
    List<Eatery> eateryList = Eatery.findAllByTags(tagList)
    Random random = new Random()
    Integer n = eateryList.size()
    Integer selection = Math.abs(random.nextInt(n))
    Eatery eatery = eateryList.get(selection)
    return eatery
}

这是错误：

 Class
org.h2.jdbc.JdbcSQLException
Message
Parameter "#1" is not set; SQL statement: select this_.id as id2_0_, this_.version as version2_0_, this_.last_visited as last3_2_0_, this_.name as name2_0_, this_.phone as phone2_0_ from eatery this_ where this_.id=? [90012-164]
Around line 16 of grails-app/services/grubspot/RandomizerService.groovy
13://14://        }15:        List<Eatery> eateryList = Eatery.findAllByTags(tagList)16:        Random random = new Random()17:        Integer n = eateryList.size()18:        Integer selection = Math.abs(random.nextInt(n))19:        Eatery eatery = eateryList.get(selection)
4

2 回答 2

1

我认为您可以使用类似于...的条件进行查询

List<Eatery> eateryList = Eatery.withCriteria{
    tags {
        "in" "id", tagList.id
    }
}

没有测试过，但应该给你一个想法

于 2013-06-17T08:44:26.907 回答
1

改变

List<Eatery> eateryList = Eatery.findAllByTags(tagList)

至

List<Eatery eateryList = Eatery.executeQuery("""
select e
from Eatery e left join e.tags as t
where t in (:tagList)""", [tagList: tagList])
于 2013-06-16T11:32:24.627 回答