Jackson: Utility class to convert object to json and json to an object

I am using below Jackson dependency.

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.9.9</version>
</dependency>

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.9.3</version>
</dependency>

Below snippet is used to convert an object to string.

public static String marshal(Object obj) throws JsonProcessingException {
 ObjectMapper mapper = new ObjectMapper();
 return mapper.writeValueAsString(obj);
}

Below snippet is used to convert json string to an object.

public static <T> T unmarshal(Class<T> clazz, String json)
  throws JsonParseException, JsonMappingException, IOException {
 ObjectMapper mapper = new ObjectMapper();
 return (T) mapper.readValue(json, clazz);
}

Find the utility class.

JacksonUtil.java

package com.sample.app.util;

import java.io.IOException;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonUtil {
 public static String marshal(Object obj) throws JsonProcessingException {
  ObjectMapper mapper = new ObjectMapper();
  return mapper.writeValueAsString(obj);
 }

 public static <T> T unmarshal(Class<T> clazz, String json)
   throws JsonParseException, JsonMappingException, IOException {
  ObjectMapper mapper = new ObjectMapper();
  return (T) mapper.readValue(json, clazz);
 }
}

Let’s test the utility class with Employee class.

Address.java

package com.sample.app.model;

public class Address {
 private String city;
 private String state;
 private String country;

 public String getCity() {
  return city;
 }

 public void setCity(String city) {
  this.city = city;
 }

 public String getState() {
  return state;
 }

 public void setState(String state) {
  this.state = state;
 }

 public String getCountry() {
  return country;
 }

 public void setCountry(String country) {
  this.country = country;
 }

 @Override
 public String toString() {
  StringBuilder builder = new StringBuilder();
  builder.append("Address [city=").append(city).append(", state=").append(state).append(", country=")
    .append(country).append("]");
  return builder.toString();
 }

}

Employee.java

package com.sample.app.model;

public class Employee {
 private int id;
 private String firstName;
 private String lastName;
 private Address address;

 public int getId() {
  return id;
 }

 public void setId(int id) {
  this.id = id;
 }

 public String getFirstName() {
  return firstName;
 }

 public void setFirstName(String firstName) {
  this.firstName = firstName;
 }

 public String getLastName() {
  return lastName;
 }

 public void setLastName(String lastName) {
  this.lastName = lastName;
 }

 public Address getAddress() {
  return address;
 }

 public void setAddress(Address address) {
  this.address = address;
 }

 @Override
 public String toString() {
  StringBuilder builder = new StringBuilder();
  builder.append("Employee [id=").append(id).append(", firstName=").append(firstName).append(", lastName=")
    .append(lastName).append(", address=").append(address).append("]");
  return builder.toString();
 }

}

App.java

package com.sample.app;

import java.io.IOException;

import com.sample.app.model.Address;
import com.sample.app.model.Employee;
import com.sample.app.util.JacksonUtil;

public class App {
 public static void main(String args[]) throws IOException {
  Employee emp = new Employee();
  emp.setId(1);
  emp.setFirstName("krishna");
  emp.setLastName("Majety");

  Address addr = new Address();
  addr.setCity("Chirala");
  addr.setCountry("India");
  addr.setState("Andhra Pradesh");
  emp.setAddress(addr);

  String serialized = JacksonUtil.marshal(emp);
  Employee emp1 = JacksonUtil.unmarshal(Employee.class, serialized);

  System.out.println(serialized);
  System.out.println(emp1);
 }
}

Run App.java, you can see below messages in console.

{"id":1,"firstName":"krishna","lastName":"Majety","address":{"city":"Chirala","state":"Andhra Pradesh","country":"India"}}
Employee [id=1, firstName=krishna, lastName=Majety, address=Address [city=Chirala, state=Andhra Pradesh, country=India]]

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