Reading JSON Array with multiple elements and appending values into JsonArray / JAVA

Question

So i have the following Json file:

["burger" : [{"Name": "Chicken Burger", "Price": 3.00},{"Name": "Cheeseburger", "Price": 2.00},{"Name": "beef burger", "Price": 2.00}]"burgerToppings" : [{"Name": "Lettuce"},{"Name": "Tomato"},{"Name":"Cucumber"},]"burgerSauces" : [{"Name": "Mayo"},{"Name": "ketchup"},{"Name": "Spicey mayo"}]]

I would like to store the "Burger" Names and price in a separate ArrayList.

A follow-up question is I would like to be able to append new values/elements into the JSONArray

Update: This is in java, eclipse

Why not do this with Jackson? Create the entities you need and let Jackson do the heavy lifting — Dan
– Dan, Commented Jul 27, 2018 at 20:11
I have been trying to use Json simple but no tutorial online and no luck myself, il try Jackson, any links/sources you reccomend? Thanks — Jahan Ulhaque
– Jahan Ulhaque, Commented Jul 27, 2018 at 20:17

Dan · Accepted Answer · 2018-07-27 20:27:29Z

1

You'll have to play around with the schema to fix some properties that are missing like burgerSausce, etc. You get the idea though

Looks like you have malformed JSON. I believe what you're looking for is:

    {"burger" : 

  { "burgerTypes" :
   [
     {"Name": "Chicken Burger", "Price": 3.00},
     {"Name": "Cheeseburger", "Price": 2.00},
     {"Name": "beef burger", "Price": 2.00}
   ]
   },

   "burgerToppings" : [
      {"Name": "Lettuce"},
      {"Name": "Tomato"},
      {"Name":"Cucumber"}
    ],
    "burgerSauces" : [  
      {"Name": "Mayo"},
      {"Name": "ketchup"},
      {"Name": "Spicey mayo"}
    ]  
}

I'd take that JSON, turn it into a schema, and run it through a converter to create some POJO's. Once you have the POJO's generated, use Jackson to do the work for you.

I went to http://www.jsonschema2pojo.org/ and generated the following:

    -----------------------------------com.example.Burger.java-----------------------------------

package com.example;

import java.util.List;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"burgerTypes"
})
public class Burger {

@JsonProperty("burgerTypes")
public List<BurgerType> burgerTypes = null;

}
-----------------------------------com.example.BurgerSauce.java-----------------------------------

package com.example;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"Name"
})
public class BurgerSauce {

@JsonProperty("Name")
public String name;

}
-----------------------------------com.example.BurgerTopping.java-----------------------------------

package com.example;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"Name"
})
public class BurgerTopping {

@JsonProperty("Name")
public String name;

}
-----------------------------------com.example.BurgerType.java-----------------------------------

package com.example;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"Name",
"Price"
})
public class BurgerType {

@JsonProperty("Name")
public String name;
@JsonProperty("Price")
public Float price;

}
-----------------------------------com.example.Example.java-----------------------------------

package com.example;

import java.util.List;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"burger",
"burgerToppings",
"burgerSauces"
})
public class Example {

@JsonProperty("burger")
public Burger burger;
@JsonProperty("burgerToppings")
public List<BurgerTopping> burgerToppings = null;
@JsonProperty("burgerSauces")
public List<BurgerSauce> burgerSauces = null;

}

Now that you have your entities you can simply call:

Burger burger = objectMapper.readValue(json, Burger.class);

edited Jul 27, 2018 at 20:27

answered Jul 27, 2018 at 20:19

Dan

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4 Comments

Jahan Ulhaque Over a year ago

Thanks! il try this tomorrow! but pretty much that's all the code I need then? Thank you very much

Dan Over a year ago

I hope you'll accept this answer once its all settled

Jahan Ulhaque Over a year ago

would you be able to add an element to a json array/hashmap? This is one of the issues I was having. Thanks for the all the help!

Dan Over a year ago

Yes, but then you would need to regenerate your pojo's. Thats why I said you're going to need to play around with it until you figure out what format you're going to use/ receive.

OneCricketeer · Accepted Answer · 2018-07-27 20:36:38Z

1

You can use JsonPath to do this easily (once you fix the JSON formatting)

[{"burger" : [{"Name": "Chicken Burger", "Price": 3.00},{"Name": "Cheeseburger", "Price": 2.00},{"Name": "beef burger", "Price": 2.00}],"burgerToppings" : [{"Name": "Lettuce"},{"Name": "Tomato"},{"Name":"Cucumber"}],"burgerSauces" : [{"Name": "Mayo"},{"Name": "ketchup"},{"Name": "Spicey mayo"}]}]

$[0].burger..Name

[
   "Chicken Burger",
   "Cheeseburger",
   "beef burger"
]

And

$[0].burger..Price

[
   3.0,
   2.0,
   2.0
]

answered Jul 27, 2018 at 20:36

OneCricketeer

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