Java - deserialize JSON array to java object with Jackson lib (from json string to java object)

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

​

import java.util.Arrays;

​

public class JacksonDeserializeArray {

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    public static void main(String[] args) throws JsonProcessingException {

​

        String usersJson = 

                "[{\"name\":\"Kate\",\"age\":24}," +

                "{\"name\":\"John\",\"age\":26}," +

                "{\"name\":\"Ann\",\"age\":25}]";

​

        ObjectMapper objectMapper = new ObjectMapper();

        User[] users = objectMapper.readValue(usersJson, User[].class);

​

        System.out.println(Arrays.toString(users));

    }

​

    private static class User {

        private String name;

        private int age;

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        // Jackson requires to have this constructor

        public User() {

​

        }

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        public User(String name, int age) {

            this.name = name;

            this.age = age;

        }

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        public String getName() {

            return name;

        }

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        public int getAge() {

            return age;

        }

​

        @Override

        public boolean equals(Object o) {

            if (this == o) return true;

            if (o == null || getClass() != o.getClass()) return false;

​

            User user = (User) o;

​

            if (age != user.age) return false;

            return name != null ? name.equals(user.name) : user.name == null;

        }

​

        @Override

        public int hashCode() {

            int result = name != null ? name.hashCode() : 0;

            result = 31 * result + age;

            return result;

        }

​

        @Override

        public String toString() {

            return "User{" +

                    "name='" + name + '\'' +

                    ", age=" + age +

                    '}';

        }

    }

}

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

​

import java.util.ArrayList;

import java.util.List;

​

public class ConvertUsersToJson {

​

    public static void main(String[] args) throws JsonProcessingException {

        List<User> users = new ArrayList<>();

        users.add(new User("Kate", 24));

        users.add(new User("John", 26));

        users.add(new User("Ann", 25));

​

        ObjectMapper objectMapper = new ObjectMapper();

        String usersJson = objectMapper.writeValueAsString(users);

​

        // [{"name":"Kate","age":24},{"name":"John","age":26},{"name":"Ann","age":25}]

        System.out.println(usersJson);

    }

​

    private static class User {

        private String name;

        private int age;

​

        // Jackson requires to have this constructor

        public User() {

​

        }

​

        public User(String name, int age) {

            this.name = name;

            this.age = age;

        }

​

        public String getName() {

            return name;

        }

​

        public int getAge() {

            return age;

        }

​

        @Override

        public boolean equals(Object o) {

            if (this == o) return true;

            if (o == null || getClass() != o.getClass()) return false;

​

            User user = (User) o;

​

            if (age != user.age) return false;

            return name != null ? name.equals(user.name) : user.name == null;

        }

​

        @Override

        public int hashCode() {

            int result = name != null ? name.hashCode() : 0;

            result = 31 * result + age;

            return result;

        }

​

        @Override

        public String toString() {

            return "User{" +

                    "name='" + name + '\'' +

                    ", age=" + age +

                    '}';

        }

    }

}