How to read values from nested JSON without using any library like GSON or org.JSON?
JSON is :
{data: { "EV_TOT_AMT" : "12" , "EV_CURR" : "INR", "T_BASKET" : [{"ORDER" : "abc", "BASE" : "xyx"},{"ORDER" : "def", "BASE" : "mno"}] } }
I want to read specific values as EV_TOT_AMT , EV_CURR , ORDER.
As far as I know, Java doesn't includes a JSON parser inside it's core classes... so if you don't want to use an external library, you'll need to build your own JSON parser.
Of course, you can just search the JSON string for your desired substrings and get the values moving into the string from the next ":" to the next "," (if the first character after the ":" is not an "["). But this isn't a good approach, unless your JSON input string is going to have always the same structure... well... actually that's not a good approach, period.
Related
below my json :
"temperature": {
"level": 8,
"format": function (value) {
return value + ' (C°)';
},
"minimum": null,
...
...
}
My goal is to write key format, I have try this but without much conviction...
package require rl_json
namespace import rl_json::json
set rj "{}"
set s1 {function (value) {
return value + ' (C°)';
}
}
json set rj temperature [json object [list level {number 8} format [json template {{"~L:s1"}}] minimum {null}]]
Error parsing JSON value: Expecting : after object key at offset 8
What you are trying to produce is not (partial) JSON, as defined, but rather general Javascript. As such, you cannot reasonably expect JSON-specific tooling (such as rl_json) to work with it. It is usually better to keep your JSON and your Javascript separated, with the data in JSON (including any dynamic generation) and your Javascript as a static artefact (or generated from something like Typescript). Mixing code and dynamic generation requires great care to get right; it is usually better to try to write things so you don't need to be that careful!
If you must do this defintely-not-advised thing, use something like subst or format to inject the variable parts (which you can generate with rl_json) in the overall string. No code for that from me: my advice is don't do that.
I have converted some columns to JSON using the columns to json node. The output from that is:
{
"Material" : 101,
"UOM" : "GRAM",
"EAN" : 7698,
"Description" : "CHALK BOX"
}
I would like to add the value of the material property as a key to each JSON object. So, my desired output is:
"101": {
"Material" : 101,
"UOM" : "GRAM",
"EAN" : 7698,
"Description" : "CHALK BOX"
}
I have tried entering the following expression in the JSON transformer node but all I get is a question mark in the new column it generates:
$Material$:{"Material":$Material$,"UOM":$UOM$,"EAN":$EAN$,"Description":$Description$}
I have also tried replacing the $Material$ with "Material" but got the same result.
How would I go about this, please?
In case you convert the Material column to String (for example with String Manipulator), you can easily configure the Columns to JSON:
As you can see the Data bound key is the important part.
The String Manipulator node configuration (string($Material$)):
I finally managed to solve this by a different method.
I split the JSON data into several columns, then used the join function to create a string in the required order. I put the resulting string through the string to JSON node to create the new JSON object.
Thanks for all your tips and comments !
I have a JSON like
{
"campaign_key": 316,
"client_key": 127,
"cpn_mid_counter": "24",
"cpn_name": "Bopal",
"cpn_status": "Active",
"clt_name": "Bopal Ventures",
"clt_status": "Active"
}
Expected output
1st JSON :
{
"campaign_key": 316,
"client_key": 127,
"cpn_mid_counter": "24",
"cpn_name": "Bopal",
"cpn_status": "Active"
}
2nd JSON:
{
"clt_name": "Bopal Ventures",
"clt_status": "Active"
}
How do I acheive this by using NIFI? Thanks.
You can do what 'user' had said. The not-so-good thing about that approach is, if you number of fields are increasing, then you are required to add that many JSON Path expression attributes to EvaluateJsonPath and subsequently add that many attributes in ReplaceText.
Instead what I'm proposing is, use QueryRecord with Record Reader set to JsonTreeReader and Record Writer set to JsonRecordSetWriter. And add two dynamic relationship properties as follows:
json1 : SELECT campaign_key, client_key, cpn_mid_counter, cpn_name, cpn_status FROM FLOWFILE
json2 : SELECT clt_name, clt_status FROM FLOWFILE
This approach takes care of reading and writing the output in JSON format. Plus, if you want to add more fields, you just have add the field name in the SQL SELECT statement.
QueryRecord processor lets you execute SQL query against the FlowFile content. More details on this processor can be found here
Attaching screenshots
Karthik,
Use EvaluateJsonPath processor to get those all json Values by using its keys.
Example: $.campaign_key for gets compaign key value and $.clt_name for get clt name.
Like above one you can get all jsons.
Then use ReplaceText Processor for convert single json into two jsons.
{"Compaign_Key":${CompaignKey},...etc}
{"Clt_name":${clt_name}}
It will convert single json into two jsons.
Hope this helpful and let me know if you have issues.
I have a function in scala that translates a value and produces a string.
strOut = translate(strIn)
Suppose the following JSON object:
{
"id": "c730433b-082c-4984-3d56-855c243265f0",
"standard": "stda",
"timestamp": "tsx000",
"stdparms" : {
"stdparam1": "a",
"stdparam2": "b"
}
}
and the following mapping provided by the translation function:
"stda" -> "stdb"
"tsx000" -> "tsy000"
"a" -> "f"
"b" -> "g"
What is the best way to translate the whole JSON object using the translate function? My goal is to obtain the following result:
{
"id": "c730433b-082c-4984-3d56-855c243265f0",
"standard": "stdb",
"timestamp": "tsy000",
"stdparms" : {
"stdparam1": "f",
"stdparam2": "g"
}
}
I must use the io.circe library due to project related matters.
If you know beforehand which fields you want to translate, or what translations apply to that field, you can use Cursors to traverse the JSON tree. Or if the fields themselves are fixed (you always know what fields to expect) Optics may require less code.
When you get to the right leaf, you apply the translation.
However, when you don't know what could apply when/where it might be easier to find/replace using string methods.
Note that the JSON you provided as an example is not valid JSON by the way.
An instance of my JAXB Object model contains an element that I want output when I generate Xml for the instance but not when I generate json
i.e I want
<release-group>
<type>Album</type>
<title>Fred</title>
</release-group>
and
"release-group" : {
"title" : "fred",
},
but have
"release-group" : {
"type" : "Album",
"title" : "fred"
},
Can I do this using the oxml.xml mapping file
This answer shows how I can do it for attributes using the transient keyword, Can I get MOXy to not output an attribute when generating json? but I cannot get that to work for an element.
Sorry problem solved, a bit of confusion on my part.
The example I gave above didn't actually match the true situation accurately, type was actually output as an attribute for Xml, but use of transient didnt work because it had been renamed in the JAXB
#XmlAttribute(name = "target-type", required = true)
#XmlSchemaType(name = "anyURI")
protected String targetType;
So adding
<java-type name="ReleaseGroup">
<java-attributes>
<xml-transient java-attribute="targetType"/>
</java-attributes>
</java-type>
worked, previously I was incorrectly doing
<java-type name="ReleaseGroup">
<java-attributes>
<xml-transient java-attribute="target-type"/>
</java-attributes>
</java-type>