grails - 无法设置只读属性:params

我正在尝试保存图片并返回它的visit-url，但是系统抛出有关params的异常:“无法设置readonly属性:params”

def upload() {
    def attachmentInstance = new Attachment(utype:params.type, udata:params.data)
    if (!attachmentInstance.save(flush: true)) {
        render(view: "create", model: [attachmentInstance: attachmentInstance])
        return
    }

    def subMap = [url:"${createLink(controller:'attachment', action:'renderImg', params:'[id:${attachmentInstance.id}]')}", width:0, height:0]

    def jsonMap = [id:attachmentInstance.id, type:"image", thumbnail:"", data:subMap]

    def result = [result:jsonMap]

    render result as JSON
}

最佳答案

看起来有点复杂，您可以尝试:

def subMap = [url:createLink(controller:'attachment', action:'renderImg', params:[id:attachmentInstance.id]), width:0, height:0]