list - Groovy/Grails : How to sort the list of objects by id

Question

公共(public)培训类

class PublicTraining{
    static hasMany = [trainingOrder: TrainingOrder]
}

和TrainingOrder类

class TrainingOrder {
    Date createdOn

    static mapping = {
        sort id:"asc"
    }
}

如果我想获得所有培训订单

def orders = publicTrainingInstance.trainingOrder.sort()
println orders // [59,58] (id of orders)

它不给出排序顺序

Answer 1

默认sort()对于Comparable对象很有用。如果您的类不是Comparable，请使用:

def orders = publicTrainingInstance.trainingOrder.sort { it.id }

该代码将使用传递的 id 进行排序。

参见文档:http://groovy.codehaus.org/groovy-jdk/java/util/Collection.html#sort()