英文:
NiFi how do I get JSON array of string converted to comma separated plain text value and substring(1024)
问题
尝试了5小时，试图将一个包含字符串值的JSON数组转换为普通字符串，用逗号分隔值并通过子字符串修剪长度。
NiFi可以做到吗？
例如，从以下开始：
[
"Charlie was here",
"Linus was here",
"Snoopy was here",
"Sally was here"
]
我尝试将其转换为：
Charlie was here,Linus was here,Snoopy was here,Sally was here
因此，如果上述值被存储到名为'myData'的属性中，
然后我可以对它进行子字符串操作，以缩短总长度，不管最后被截掉什么。
例如：
myData:substring(0,1024)
我尝试使用以下处理器，各种组合，但没有找到正确的处理器。
- UpdateAttribute
- EvaluateJSONPath
- SplitJSON
- MergeContent
我最接近的是使用splitjson和mergecontent，但然后内容中没有逗号分隔值，我最终得到了：
Charlie was hereLinus was hereSnoopy was hereSally was here
我在这里找到的几乎所有内容都涉及将文本转换为JSON，而不是将JSON转换为文本。
我错过了哪个处理器？
英文:
Been at this for 5 hours trying to convert a JSON array of string values to a plain string comma separated value and trim the length via substring.
Can NiFi do this?
e.g.
Starting with
[
"Charlie was here",
"Linus was here",
"Snoopy was here",
"Sally was here"
]
I am trying to convert it to
Charlie was here,Linus was here,Snoopy was here,Sally was here
So if the above value gets stored into an attribute called 'myData'
then I can substring it to shorten the overall length and it does not matter what gets chopped off at the end.
e.g.
myData:substring(0,1024)
I have been trying to use the following processors, various combinations but have not been able to find the correct one to use.
- UpdateAttribute
- EvaluateJSONPath
- SplitJSON
- MergeContent
The closest I got is with the splitjson and mergecontent but then the content contains no comma separating the values and I end up with
Charlie was hereLinus was hereSnoopy was hereSally was here
Just about everything I have found posted in here deals with text convert to json but not json convert to text.
What processor am I missing here?
答案1
得分: 1
一个选择是使用JoltTransformJSON处理器，具体规范如下：
[
{
"operation": "shift",
"spec": {
"*": "&1[]"
}
},
{
"operation": "modify-overwrite-beta",
"spec": {
"*": "=join(',',@(1,&))"
}
},
{// 仅导出扁平化后的字符串
"operation": "shift",
"spec": {
"*": ""
}
}
]
该网站上的演示地址为：
英文:
An option would be using JoltTransformJSON processor with the following specification :
[
{
"operation": "shift",
"spec": {
"*": "&1[]"
}
},
{
"operation": "modify-overwrite-beta",
"spec": {
"*": "=join(',',@(1,&))"// concatenate all string components separated by comma
}
},
{// derive the unnested string only
"operation": "shift",
"spec": {
"*": ""
}
}
]
the demo on the site http://jolt-demo.appspot.com/ is :
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