Grails 使用 gstring 访问嵌套字段

发布于 2024-12-10 17:33:00 字数 446 浏览 1 评论 0原文

我正在尝试使用 gstring 访问嵌套字段，但它抛出异常 groovy.lang.MissingPropertyException

我有两个类

Class Person{
   Address address
}
Class Address{
  String city
}

在我正在执行的代码中的某个位置，

def person = Person.get(1)
def field = "address.city"
def city = person."${field}"

我尝试从 person 获取城市的行抛出 groovy.lang.MissingPropertyException

如果我尝试使用 gstring 获取直接属性，它可以工作，但上面给出的代码不起作用。

有什么帮助吗？

原文

I am trying to access a nested field using gstring but it throws exception groovy.lang.MissingPropertyException

I have two classes

Class Person{
   Address address
}
Class Address{
  String city
}

Somewhere in my code I am doing,

def person = Person.get(1)
def field = "address.city"
def city = person."${field}"

The line where I am trying to fetch city from person is throwing groovy.lang.MissingPropertyException

If I try to fetch a direct property using gstring it works but the above given code doesnt work.

Any help?

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信愁 2024-12-17 17:33:00

您在这里所做的是尝试通过名称 address.city 访问属性，该属性等于 person."address.city"，这意味着这里的点得到被视为属性名称的一部分 - 而不是您期望的访问分隔符。以下代码应该可以解析您的属性：

def city = field.tokenize('.').inject(person) {v, k -> v."$k"}

What you're doing here is trying to access a property by name address.city which is equal to person."address.city", which means that the dot here gets considered as part of property name - not as access separator as you expect. The following code should resolve your property:

def city = field.tokenize('.').inject(person) {v, k -> v."$k"}

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梦屿孤独相伴 2024-12-17 17:33:00

我认为问题在于访问子属性的点运算符。

这有效：

class Person{
   String address
}

def person = new Person(address:'Madrid')

def field = 'address'
assert 'Madrid' == person."${field}"

这有效：

class Person{
   Address address
}

class Address {
  String city
}

def person = new Person(address: new Address(city: 'Madrid'))

def field = 'address'
def subField = 'city'
assert 'Madrid' == person."${field}"."${subField}"

I think that the problem is with dot operator for access to a subproperty.

This works:

class Person{
   String address
}

def person = new Person(address:'Madrid')

def field = 'address'
assert 'Madrid' == person."${field}"

This works:

class Person{
   Address address
}

class Address {
  String city
}

def person = new Person(address: new Address(city: 'Madrid'))

def field = 'address'
def subField = 'city'
assert 'Madrid' == person."${field}"."${subField}"

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