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How do I create an ElasticSearch query without knowing what the field is?

I have someone putting JSON objects into Elasticsearch for which I do not know any fields. I would like to search all the fields for a given value using a matchQuery.
I understand that the _all is deprecated, and the copy_to doesn't work because I don't know what fields are available beforehand. Is there a way to accomplish this without knowing what fields to search for beforehand?

Yes, you can achieve this using a custom _all field (which I called my_all) and a dynamic template for your index. Basically, this idea is to have a generic mapping for all fields with a copy_to setting to the my_all field. I've also added store: true for the my_all field but only for the purpose of showing you that it works, in practice you won't need it.
So let's go and create the index:
PUT my_index
{
"mappings": {
"_doc": {
"dynamic_templates": [
{
"all_fields": {
"match": "*",
"mapping": {
"copy_to": "my_all"
}
}
}
],
"properties": {
"my_all": {
"type": "text",
"store": true
}
}
}
}
}
Then index a document:
PUT my_index/_doc/1
{
"test": "the cat drinks milk",
"age": 10,
"alive": true,
"date": "2018-03-21T10:00:00.123Z",
"val": ["data", "data2", "data3"]
}
Finally, we can search using the my_all field and also show its content (because we store its content) in addition to the _source of the document:
GET my_index/_search?q=my_all:cat&_source=true&stored_fields=my_all
And the result is shown below:
{
"_index": "my_index",
"_type": "_doc",
"_id": "1",
"_score": 0.2876821,
"_source": {
"test": "the cat drinks milk",
"age": 10,
"alive": true,
"date": "2018-03-21T10:00:00.123Z",
"val": [
"data",
"data2",
"data3"
]
},
"fields": {
"my_all": [
"the cat drinks milk",
"10",
"true",
"2018-03-21T10:00:00.123Z",
"data",
"data2",
"data3"
]
}
}
So given you can create the index and mapping of your index, you'll be able to search whatever people are sending to it.

How to get value from json object with java obect mapper

I want to get the value at the field first inside name.
How i can access in this field using HashMap in java
{ "payload":{
"name": {
"first": "jean",
"last": "bob,
},
"address": {
"code": "75",
"city": "paris",
"country": "France"
},
}}

Use one of the available Java libraries for handling JSON. E.g. Gson from Guava API. They are pretty straing fw.

JSONObject["featured_image"] is not a String

Hi all I am getting a following json from Wordpress rest APi Call
[
{
"ID": 248,
"post_title": "test post",
"post_author": "admin",
"excerpt": "",
"url": "http://localhost/wp-learning/?p=248",
"permalink": "http://192.168.10.31/wp-learning/test-post/",
"post_date": "2017-08-07 09:15:57",
"comment_count": "2",
"category": [
{
"term_id": 1,
"name": "Uncategorized",
"slug": "uncategorized",
"term_group": 0,
"term_taxonomy_id": 1,
"taxonomy": "category",
"description": "",
"parent": 0,
"count": 1,
"filter": "raw",
"cat_ID": 1,
"category_count": 1,
"category_description": "",
"cat_name": "Uncategorized",
"category_nicename": "uncategorized",
"category_parent": 0
}
],
"views": "4",
"featured_image": false
},
{
"ID": 247,
"post_title": "The Coolest Vanity Apps for You and Your Girls",
"post_author": "admin",
"excerpt": "",
"url": "http://td_uid_79_598817d2cebf2",
"permalink": "http://192.168.10.31/wp-learning/the-coolest-vanity-apps-for-you-and-your-girls/",
"post_date": "2017-08-07 07:33:38",
"comment_count": "0",
"category": [
{
"term_id": 15,
"name": "Beauty",
"slug": "beauty",
"term_group": 0,
"term_taxonomy_id": 15,
"taxonomy": "category",
"description": "On each category you can set a Category template style, a Top post style (grids) and a module type for article listing.",
"parent": 14,
"count": 17,
"filter": "raw",
"cat_ID": 15,
"category_count": 17,
"category_description": "On each category you can set a Category template style, a Top post style (grids) and a module type for article listing.",
"cat_name": "Beauty",
"category_nicename": "beauty",
"category_parent": 14
}
],
"views": "0",
"featured_image": "http://192.168.10.31/wp-learning/wp-content/uploads/2017/08/3.jpg"
}
]
I am problem in fetching the tag name "featured_image". what type of datatype is it? i tried
jsonObj.getString("featured_image");
for this it gave me error JSONObject["featured_image"] is not a String.
also
resultsObj.getJSONObject("featured_image").toString()
for this it gave me error JSONObject["featured_image"] is not a JSONObject.

You are doing resultsObj.getJSONObject("featured_image").toString() which asks to get a JSON Object out of the Key/Value at 'featured_image'.
But we can see that the value is a string, or a bool:
"featured_image": "http://192.168.10.31/wp-learning/wp-content/uploads/2017/08/3.jpg"
"featured_image": false
So you should not call getJSONObject() on this key, at all.

Based on your JSON Structure, it looks like the "featured_image" is of boolean type, it is not string or object.

I think its inner json problem
try like this :
JSONObject category = jsonObj.getJSONObject("category");
category.getJSONObject("featured_image");

You can use following code, I didn't tested but that can be helpful in determining the data type and based on the type you can decide which method needs to be called.
So use:
JsonValue type = resultsObj.get("featured_image").getValueType();
if (type.getValueType() == JsonValue.ValueType.TRUE || type.getValueType() == JsonValue.ValueType.FALSE){
// call boolean method
boolean bValue = resultsObj.get("featured_image").getAsBoolean()
}else{
//based on you type you can call respective method.
}
Refer following link:
JsonValueType
getValueType

How do I convert a list represented as a string to a list?

I am building an Android application which reads from themoviedb.org.
What I am trying to do is have the user enter a movie title and use that title to find its id.
When I run the query to search for movies, I get a response like:
{
"page": 1,
"results": [
{
"poster_path": "aaaaa.jpg",
"id": "11",
"description": "MovieDescription"
},
{
"poster_path": "bbbbb.jpg",
"id": "12",
"description": "MovieDescription2"
},
{
"poster_path": "ccccc.jpg",
"id": "13",
"description": "MovieDescription"
}
]
}
Using the Maven JSON library, I can fetch the results key as a string using json.get("results").
returning:
[
{
"poster_path": "aaaaa.jpg",
"id": "11",
"description": "MovieDescription"
},
{
"poster_path": "bbbbb.jpg",
"id": "12",
"description": "MovieDescription2"
},
{
"poster_path": "ccccc.jpg",
"id": "13",
"description": "MovieDescription"
}
]
But I want to convert the first of these results to another JSONObject so that I can get the movie's id from the first result.
I'm thinking that the way to do this is to convert the results value to a list of JSONObject and then use the json.get("id") method on the first object in the list. But I do not know how to do this conversion.
Any help would be appreciated.

You can use JSONObject.getJSONArray to get the result directly as a JSON Array:
JSONArray results = json.getJSONArray("results") // Get results as JSON Array
JSONObject first = results.getJSONObject(0) // Get first object as JSON Object
See: JSONObject#getJSONArray(String)

Checking Keys in JSON Records using Java

"transaction": {
"id": 1,
"empid": "12345",
"details1": {
"name": "xyz",
"age": "30",
"sex": "M",
"Address": {
"Office": "office",
"Home": "Home"
}
},
"abcDetails": "asdf",
"mobile": 123455
},
I need to test if JSON record contains more then two keys(details, Address).
Then, I need to pass those key input to this line:
parserValue1 = parserValue.asObject().get("firstKey").asObject().get("secondKey");
Can anyone help me?

Many json parsers have a has("key") or contains("key") accessor.
Otherwise you will have to add a condition to check if get("") returns null, or turn your whole Json object into a map, where you do the same checks.