Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to map the JSON data with Jackson Object Model in Java?
The ObjectMapper class provides functionality for converting between Java objects and matching JSON constructs. We can achieve mapping of JSON data represented by an Object Model to a particular Java object using a tree-like data structure that reads and stores the entire JSON content in memory. In the first step, read the JSON data into the JsonNode object then mapped it to another instance by calling the treeToValue() method of ObjectMapper class.
Syntax
public <T> T treeToValue(TreeNode n, Class<T> valueType) throws JsonProcessingException
Example
import java.io.*;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.*;
public class JsonTreeModelDemo {
public static void main(String[] args) throws JsonProcessingException, IOException {
String jsonString = "{\"id\":\"102\", \"name\":\"Raja Ramesh\", \"address\":[{\"area\":\"Madhapur\", \"city\":\"Hyderabad\"}]}";
ObjectMapper objectMapper = new ObjectMapper();
JsonNode jsonNode = objectMapper.readTree(jsonString);
User user = objectMapper.treeToValue(jsonNode, User.class);
System.out.println(user);
}
}
// User class
class User {
private int id;
private String name;
private Address[] address;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Address[] getAddress() {
return address;
}
public void setAddress(Address[] address) {
this.address = address;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("{");
sb.append(id).append(",");
sb.append(name).append(",");
for(Address address1 : address) {
sb.append(address1).append(",");
}
sb.append("}");
return sb.toString();
}
}
// Address class
class Address {
private String area;
private String city;
public String getArea() {
return area;
}
public void setArea(String area) {
this.area = area;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("{");
sb.append(area).append(",");
sb.append(city);
sb.append("}");
return sb.toString();
}
}Output
{102,Raja Ramesh,{Madhapur,Hyderabad},}
Updated on: 07-Jul-2020
2K+ Views
Advertisements