Java ObjectMapper-class And Method Code Example

Here is an example of how to use the ObjectMapper class from the com.fasterxml.jackson.databind package in Java:

import com.fasterxml.jackson.databind.ObjectMapper;

public class MyClass {
    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper();

        // Example of deserializing JSON to a Java object
        MyObject obj = mapper.readValue("{\"name\":\"John\",\"age\":30}", MyObject.class);
        System.out.println(obj.getName()); // prints "John"
        System.out.println(obj.getAge()); // prints 30

        // Example of serializing a Java object to JSON
        String json = mapper.writeValueAsString(obj);
        System.out.println(json); // prints {"name":"John","age":30}

        // Example of deserializing JSON to a Map
        Map<String, Object> map = mapper.readValue("{\"name\":\"John\",\"age\":30}", new TypeReference<Map<String, Object>>(){});
        System.out.println(map.get("name")); // prints "John"
        System.out.println(map.get("age")); // prints 30

class MyObject {
    private String name;
    private int age;

    // getters and setters

This example creates an instance of ObjectMapper. The ObjectMapper class is used to convert between JSON and Java objects. In this example, it is used to deserialize JSON into a MyObject instance and to serialize a MyObject instance to JSON. Also it shows how to deserialize JSON to a Map.

TypeReference is used to provide the type information for the mapping.

readValue method is used to deserialize JSON to a Java object or Map.

writeValueAsString method is used to serialize a Java object to a JSON string.