Binding JSON to POJO

We will see simple Java class Employee being transformed to and from JSON String.

Following is project structure generated by Maven

Following is POM.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>custom.jackson</groupId>
  <artifactId>learning</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>learning</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
	      <groupId>junit</groupId>
	      <artifactId>junit</artifactId>
	      <version>3.8.1</version>
	      <scope>test</scope>
    </dependency>
    <dependency>
	    <groupId>com.fasterxml.jackson.core</groupId>
	    <artifactId>jackson-core</artifactId>
	    <version>2.12.3</version>
   </dependency>
   <dependency>
	    <groupId>com.fasterxml.jackson.core</groupId>
	    <artifactId>jackson-databind</artifactId>
	    <version>2.12.3</version>
	</dependency>
	<dependency>
	    <groupId>com.fasterxml.jackson.core</groupId>
	    <artifactId>jackson-annotations</artifactId>
	    <version>2.12.3</version>
	</dependency>
  </dependencies>
</project>

Bean class Employee.java

package custom.jackson.learning;

public class Employee {

	private String firstName;
	private String lastName;
	private boolean isCertified;
	private int age;
	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 boolean isCertified() {
		return isCertified;
	}
	public void setCertified(boolean isCertified) {
		this.isCertified = isCertified;
	}
	@Override
	public String toString() {
		return "Employee [firstName=" + firstName + ", lastName=" + lastName + ", isCertified=" + isCertified + ", age="
				+ age + "]";
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	
	
}

package custom.jackson.learning;

import java.io.IOException;

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

/**
 * Hello world!
 *
 */
public class App 
{
    public static void main( String[] args )
    {
    		      ObjectMapper mapper = new ObjectMapper();
    		      String jsonString = "{\"firstName\":\"Suresh\", \"lastName\":\"Rana\", \"certified\":\"true\", \"age\":21}";
    		      
    		      try{
    		    	  
    		    	 //Transform JSON to Employee Object
    		         Employee employee_Suresh = mapper.readValue(jsonString, Employee.class);
    		         
    		         System.out.println("print Java object");
    		         System.out.println(employee_Suresh);
    		         
    		         //Transform Employee object to JSON
    		         jsonString = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(employee_Suresh);
    		         
    		         System.out.println("print json converted string");
    		         System.out.println(jsonString);
    		      }
    		      catch (JsonParseException e) { e.printStackTrace();}
    		      catch (JsonMappingException e) { e.printStackTrace(); }
    		      catch (IOException e) { e.printStackTrace(); }
    }
}

Output