从地图更新常规对象字段 [英] Updating groovy object fields from a map

问题描述

在 groovy 中，我们可以轻松地从地图创建对象并自动填充相应的字段:

In groovy we can easily create objects from maps and fill the corresponding fields automatically:

def myAddress = new Address([street:"King's street", number:"1200"])

是否也可以在不重新创建地图的情况下更新现有对象?像……

Is it possible to also update an existing object from a map without recreating it? Something like...

myAddress.update([zip: "30555050", city: "London"])

推荐答案

您可以使用 object."${variable}" 访问器来做到这一点:

You can use object."${variable}" accessors to do this:

map.each { key, value ->
    object."${key}" = value
}

然后您可以创建一个执行此操作的方法并将其安装在 Object.metaClass 上，它将随处可用:

You can then create a method that does this and install that on Object.metaClass and it will be available everywhere:

@Canonical
class MapSet {

    String name
    int count

    static def setAttributesFromMap(Object o, Map<String, Object> map) {
        map.each { key, value ->
            o."${key}" = value
        }
    }

    static void main(String[] args) {
        Object.metaClass.update = {
            setAttributesFromMap delegate, it
        }

        def o = new MapSet([
                name: "foo",
                count: 5
        ])

        assert o.name == "foo"
        assert o.count == 5

        o.update([
                name: "bar",
                count: 6
        ])

        assert o.name == "bar"
        assert o.count == 6
    }
}

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