在Groovy中使用JSONBuilder排除空值 [英] Exclude null values using JSONBuilder in Groovy

问题描述

是否可以使用默认的JsonBuilder库在Groovy中创建JSON值，以排除对象的所有空值?例如Jackson在Java中通过注释类以排除空值的方式.

Is it possible to create JSON values in Groovy using the default JsonBuilder library to exclude all the null values of an object? Such as what Jackson does in Java by annotating classes to exclude null values.

一个例子是:

{
   "userId": "25",
   "givenName": "John",
   "familyName": null,
   "created": 1360080426303
}

应打印为:

{
   "userId": "25",
   "givenName": "John",
   "created": 1360080426303
}

推荐答案

由于我的方法在具有List属性的Map上工作，因此不确定是否适合您:

Not sure if it's OK for you as my method works on a Map with List properties:

def map = [a:"a",b:"b",c:null,d:["a1","b1","c1",null,[d1:"d1",d2:null]]]

def denull(obj) {
  if(obj instanceof Map) {
    obj.collectEntries {k, v ->
      if(v) [(k): denull(v)] else [:]
    }
  } else if(obj instanceof List) {
    obj.collect { denull(it) }.findAll { it != null }
  } else {
    obj
  }
}

println map
println denull(map)

产量:

[a:a, b:b, c:null, d:[a1, b1, c1, null, [d1:d1, d2:null]]]
[a:a, b:b, d:[a1, b1, c1, [d1:d1]]]

过滤掉null的值之后，您可以将Map呈现为JSON.

After filter null values out, you then can render the Map as JSON.

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