This post explains how to write json data to a file using JsonGenerator. The previous post explains the same using JsonWriter. The difference is that to use JsonWriter we need to build the entire object (which represents json data) in memory before writing to a file. Whereas with JsonGenerator we dont need to build the entire object. The code explains how to write the below json data

{
    "firstName": "Duke",
    "lastName": "Java",
    "age": 18,
    "streetAddress": "100 Internet Dr",
    "city": "JavaTown",
    "state": "JA",
    "postalCode": "12345",
    "phoneNumbers": [
        { "Mobile": "111-111-1111" },
        { "Home": "222-222-2222" }
    ]
}

Code

package objectmodel;

import java.io.FileWriter;
import java.io.IOException;

import javax.json.Json;
import javax.json.stream.JsonGenerator;

public class Example7 {
    public static void main(String[] args) {
        try(FileWriter fw = new FileWriter("E:\\Projects\\JavaProjects\\JavaJSONProject\\jsondata4.txt");
        JsonGenerator jsonGenerator = Json.createGenerator(fw);) {
            jsonGenerator.writeStartObject(); //Writes the character '{'
            jsonGenerator.write("firstName","Duke");
            jsonGenerator.write("lastName","Duke");
            jsonGenerator.write("age",18);
            jsonGenerator.write("streetAddress","100 Internet Dr");
            jsonGenerator.write("city","JavaTown");
            jsonGenerator.write("state","JA");
            jsonGenerator.write("postalCode","12345");

            jsonGenerator.writeStartArray("phoneNumbers"); //Writes the character '['
            jsonGenerator.writeStartObject();
            jsonGenerator.write("Mobile","111-111-1111");
            jsonGenerator.writeEnd();
            jsonGenerator.writeStartObject();
            jsonGenerator.write("Home","222-222-2222");
            jsonGenerator.writeEnd();
            jsonGenerator.writeEnd(); //Writes the character ']'

            jsonGenerator.writeEnd(); //Writes the character '}'
        } catch(IOException excep){
            excep.printStackTrace();
        }
    }
}