grails - 将购物车对象链接到用户对象

Question

美好的一天。我是grails的新手，我必须设计一个音乐购物类型的应用程序。我有一个Cart域和一个User域，我想做的是在创建新的User对象时也要创建一个新的Cart对象，该对象也链接到User中的所说User对象。我正在使用静态脚手架，因此我想在“用户/保存”操作中执行此操作。这是我的代码:

class Cart {
    String item
    Integer quantity
    BigDecimal price
    String type
    Integer typeId
    User user
    static constraints = {
        type nullable:false, blank:false, inList:["Album", "Song", "Empty"]
        typeId nullable:false, blank:false
    }
}

class User {
    String username
    String password
    String fName
    String lName
    String email
    static constraints = {
        username(nullable : false, blank : false, minSize : 1)
        password(nullable : false, blank : false, minSize : 1)
        fName(nullable : false, blank : false, minSize : 1)
        lName(nullable : false, blank : false, minSize : 1)
        email(nullable : false, blank : false, email : true)
    }
}

class UserController {
    //static scaffolded code (index, show, create, etc.)
    @Transactional
    def save(User userInstance){     //This whole method is also generated with scaffolding 
        if (userInstance == null) {
            notFound()
            return
        }

        if (userInstance.hasErrors()) {
            respond userInstance.errors, view: 'create'
            return
        }

        userInstance.save flush: true

        //This is what I've been trying to do but it doesn't work and I don't know why :(
        def myCart = new Cart(user:userInstance, item:'empty item', quantity:0, price:0, total:0, type:'Empty', typeId:0).save(flush:true)

        //Rest of the generated code
    }
    //More generated code
}

任何帮助，将不胜感激。谢谢!

Answer 1

Cart类中有2个错误。
首先:将typeID更新为typeId
第二:类型应为String，而不是BigDecimal