Json嵌套对象检查是否为空 [英] Json nested Objects check if null

问题描述

考虑以下json

{  
   "sub1":{  
     "name":"Name-sub1",
     "sub11":{
       "name":"Name-sub11",
       "sub111":{
         "name":"Name-sub111",
         ...
       },
       ..
     },
     ...
   },
   ...
}

我现在想在Java中获取内部名称Element(名称-sub111)(这是io.vertx.core.json.JsonObject)

I now want to fetch the inner name Element (Name-sub111) in java (it's a io.vertx.core.json.JsonObject)

object.getJsonObject("sub1").getJsonObject("sub11").getJsonObject("sub111").getString("name")

但是我不确定sub1还是sub11或sub111是否存在-所以我总是需要检查null

But I'm not sure if sub1 or sub11 or sub111 even exist - so I always need to check for null

if(object.getJsonObject("sub1") != null && object.getJsonObject("sub1").getJsonObject("sub11") != null && object.getJsonObject("sub1").getJsonObject("sub11").getJsonObject("sub111") != null) {
    return object.getJsonObject("sub1").getJsonObject("sub11").getJsonObject("sub111").getString("name");
}

有人知道这种情况下更好的解决方案吗?

Does someone know a better solutions for this case?

推荐答案

此处的一个选项是使用Java 8 Optional，它消除了重复的方法调用.但是，对于某些人来说，最终结果可能看起来不够清晰:

an option here is to use Java 8 Optional, which eliminates the dupplicate method calls. Howewver, the end result might not look clear enough for some:

    return Optional.ofNullable(object.getJsonObject("sub1")).map(subObj1 -> 
        Optional.ofNullable(subObj1.getJsonObject("sub11")).map(subObj11 ->
            Optional.ofNullable(subObj11.getJsonObject("sub111")).map(subObj111 -> subObj111.getString("name") 
    )));

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