How to create a nameless Json array with Jackson

» json » How to create a nameless Json array with Jackson

By : user3038557

Date : November 24 2020, 12:01 PM

I wish this helpful for you It seems that you might want to just omit the root object declaration and leave it as an array, as it not a valid json format.

code :

JsonGenerator generator = factory.createGenerator(os, JsonEncoding.UTF8);
generator.writeStartArray();
while (rs.next()) {
    generator.writeStartObject();
    generator.writeStringField("value", rs.getString("value"));
    generator.writeEndObject();
}
generator.writeEndArray(); 
generator.close();

[{"value":"1"}, {"value":"2"}, {"value":"3"}, {"value":"4"}]

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Create a valid JSON using Jackson that contains an array and a custom field

By : A.H

Date : March 29 2020, 07:55 AM

may help you . I think you can use Hashmap. Jackson will understand how to apply filter to the Object in array and will just skip any other object(String/array) it finds. Here is demo, that works for me:

code :

import com.fasterxml.jackson.annotation.JsonFilter;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.ser.FilterProvider;
import com.fasterxml.jackson.databind.ser.impl.SimpleBeanPropertyFilter;
import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;
import org.json.JSONException;

import java.io.IOException;
import java.util.HashMap;

public class test12 {
    public static void main(String[] args) throws IOException, JSONException {
        Object[] allUsers = get_all_users();

        String[] ignorableFieldNames = {"skip"};

        ObjectMapper mapper = new ObjectMapper();
        mapper.enable(SerializationFeature.INDENT_OUTPUT);

        mapper.addMixIn(Object.class, PropertyFilterMixIn.class);
        FilterProvider filters = new SimpleFilterProvider()
                .addFilter("filter properties by name",
                        SimpleBeanPropertyFilter.serializeAllExcept(
                                ignorableFieldNames));
        mapper.setFilterProvider(filters);

        HashMap<String, Object> map = new HashMap<String, Object>();
        map.put("users", allUsers);
        map.put("uri", "/users");
        String result = mapper.writeValueAsString(map);

        System.out.println(result);
    }

    @JsonFilter("filter properties by name")
    public static class PropertyFilterMixIn {
    }

    private static Object[] get_all_users() {
        User user1 = new User();
        user1.foo = "abc1";
        user1.bar = "def1";
        user1.skip = "this field is skipped";
        User user2 = new User();
        user2.foo = "abc2";
        user2.bar = "def2";
        user2.skip = "this field is skipped";
        return new Object[]{user1, user2};
    }

    public static class User {
        public String foo;
        public String bar;
        public String skip;
    }
}

{
  "users" : [ {
    "foo" : "abc1",
    "bar" : "def1"
  }, {
    "foo" : "abc2",
    "bar" : "def2"
  } ],
  "uri" : "/users"
}

Simple nameless json array convert to mapped JS or PHP array

By : LikeSE

Date : March 29 2020, 07:55 AM

Does that help You have a 2 dimensional array. To split it into columns, you can just iterate the array and push the values into new arrays

code :

var data = [[1,2],[1,2]];
var firstValues=[];
var secondValues=[];
for(var i=0; i < data.length; i++){
    firstValues.push(data[i][0]);
    secondValues.push(data[i][1]);
}

Parsing a nameless JSON array in Java

By : rafa00706

Date : March 29 2020, 07:55 AM

Hope this helps The correct way:
Parse this as an array using JSONArray(String)1:

how to create json array using jackson

By : j v

Date : March 29 2020, 07:55 AM

I wish this help you Can you build the array as an object before writing it, rather than bothering with all the individual pieces?

Create a CN1 JSON Array from POJO for Jackson

By : Jawrow92

Date : March 29 2020, 07:55 AM

it helps some times I'm doing pretty similar things with my app ! Eg : SQLite database with cn1-data-access library for cn1 application and server side with hibernate and jackson plugin.
I've developped method to map/unmap object recursively in cn1-data-access plugin.