How to Convert a JSON String to a Map in Java - Step by Step Examples

How to Convert a JSON String to a Map in Java ?

Answer

To convert a JSON string to a map in Java, you can use the Jackson library, which provides methods to parse JSON data and convert it into a map.

✐ Examples

1 Converting a JSON String to a Map

We can convert a JSON string to a map in Java by using the Jackson library's ObjectMapper class to parse the JSON string and convert it into a map.

For example,

We start by importing the necessary classes from the Jackson library: com.fasterxml.jackson.databind.ObjectMapper and java.util.Map.
We create an instance of the ObjectMapper class.
We define a JSON string containing key-value pairs.
We use the readValue method of the ObjectMapper instance to parse the JSON string into a map.
We print the resulting map to the console to verify the conversion.

Java Program

import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.Map;

public class JsonToMapExample {
    public static void main(String[] args) {
        try {
            // Create an instance of ObjectMapper
            ObjectMapper objectMapper = new ObjectMapper();

            // Define a JSON string
            String jsonString = "{\"1\": 10, \"2\": 20, \"3\": 30, \"4\": 40, \"5\": 50}";

            // Parse the JSON string into a map
            Map<String, Integer> myMap = objectMapper.readValue(jsonString, Map.class);

            // Print the resulting map
            System.out.println("Map from JSON string:");
            myMap.forEach((key, value) -> System.out.println(key + ": " + value));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Output

Map from JSON string:
1: 10
2: 20
3: 30
4: 40
5: 50

Summary

In this tutorial, we learned How to Convert a JSON String to a Map in Java language with well detailed examples.

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