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.