list to json java example

stackoverflow.com › questions › 14228912 › how-to-convert-list-to-json-in-java

Use GSON library for that. Here is the sample code

List<String> foo = new ArrayList<String>();
foo.add("A");
foo.add("B");
foo.add("C");

String json = new Gson().toJson(foo );

Here is the maven dependency for Gson

<dependencies>
    <!--  Gson: Java to Json conversion -->
    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>2.2.2</version>
        <scope>compile</scope>
    </dependency>
</dependencies>

Or you can directly download jar from here and put it in your class path

http://code.google.com/p/google-gson/downloads/detail?name=gson-1.0.jar&can=4&q=

To send Json to client you can use spring or in simple servlet add this code

response.getWriter().write(json);

Answer from code_fish on Stack Overflow

Baeldung

baeldung.com › home › java › java list › converting a java list to a json array

Converting a Java List to a Json Array | Baeldung

June 18, 2025 - In addition to external libraries like Gson and Jackson, Java also provides a built-in library called org.json for JSON processing. To convert a Java List to a JSON array using org.json, we can use the JSONArray class to accomplish this task. Here’s an example:

Stack Overflow

stackoverflow.com › questions › 14228912 › how-to-convert-list-to-json-in-java

How to convert List to Json in Java - Stack Overflow

Top answer

1 of 8

153

Use GSON library for that. Here is the sample code

List<String> foo = new ArrayList<String>();
foo.add("A");
foo.add("B");
foo.add("C");

String json = new Gson().toJson(foo );

Here is the maven dependency for Gson

<dependencies>
    <!--  Gson: Java to Json conversion -->
    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>2.2.2</version>
        <scope>compile</scope>
    </dependency>
</dependencies>

Or you can directly download jar from here and put it in your class path

http://code.google.com/p/google-gson/downloads/detail?name=gson-1.0.jar&can=4&q=

To send Json to client you can use spring or in simple servlet add this code

response.getWriter().write(json);

2 of 8

14

You need an external library for this.

JSONArray jsonA = JSONArray.fromObject(mybeanList);
System.out.println(jsonA);

Google GSON is one of such libraries

You can also take a look here for examples on converting Java object collection to JSON string.

Discussions

How to convert List to Json String in java (com.amazonaws.util.json.JSONObject) - Stack Overflow

@VinaySawant Right, ObjectMapper is for Java -> JSON objects. You can just use toString(), changed my answer. – Florian Albrecht Commented Apr 4, 2018 at 12:18 ... List jsons = new ArrayList<>(); jsons.add(new JSONObject(ImmutableMap.of("Attribute", "EmailAddress", "Value", "[email ... More on stackoverflow.com

stackoverflow.com

How to parse json to get size of the list using jsonObject in java?

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r/javahelp

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May 16, 2022

Spring Boot - make json conversion use float[] instead of List<Double>

My initial answer (more digging possible later) is “no, you can’t.” Or at least, no you can’t the way you are doing it. You are deserializing to Map. The deserializer gets to pick everything then. To do more, you start needing to have a target object to deserialize to instead. You can write your own custom deserializer and go from there: https://www.baeldung.com/jackson-deserialization and http://tutorials.jenkov.com/java-json/jackson-objectmapper.html#custom-deserializer go into that. That said, I have to ask why you want a float array instead? More on reddit.com

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September 11, 2018

How to turn json objects into an array of json objects using Java?

Please ensure that: Your code is properly formatted as code block - see the sidebar (About on mobile) for instructions You include any and all error messages in full You ask clear questions You demonstrate effort in solving your question/problem - plain posting your assignments is forbidden (and such posts will be removed) as is asking for or giving solutions. Trying to solve problems on your own is a very important skill. Also, see Learn to help yourself in the sidebar If any of the above points is not met, your post can and will be removed without further warning. Code is to be formatted as code block (old reddit: empty line before the code, each code line indented by 4 spaces, new reddit: https://imgur.com/a/fgoFFis ) or linked via an external code hoster, like pastebin.com, github gist, github, bitbucket, gitlab, etc. Please, do not use triple backticks (```) as they will only render properly on new reddit, not on old reddit. Code blocks look like this: public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } } You do not need to repost unless your post has been removed by a moderator. Just use the edit function of reddit to make sure your post complies with the above. If your post has remained in violation of these rules for a prolonged period of time (at least an hour), a moderator may remove it at their discretion. In this case, they will comment with an explanation on why it has been removed, and you will be required to resubmit the entire post following the proper procedures. To potential helpers Please, do not help if any of the above points are not met, rather report the post. We are trying to improve the quality of posts here. In helping people who can't be bothered to comply with the above points, you are doing the community a disservice. I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns. More on reddit.com

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June 28, 2022

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Convert JSON String to List of Objects with Gson in Java - YouTube

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