Jackson - Full Data Binding

Full data binding refers to mapping of JSON to any Java Object.

//Create an ObjectMapper instance
ObjectMapper mapper = new ObjectMapper(); 

//map JSON content to Student object
Student student = mapper.readValue(new File("student.json"), Student.class);

//map Student object to JSON content
mapper.writeValue(new File("student.json"), student);

Full Data Binding Example

Let us take a simple example to understand full data binding in detail. In the following example, we will map a Java Object directly to JSON and vice versa.
Create a Java class file named JacksonTester in C:\>Jackson_WORKSPACE.

File: JacksonTester.java

import java.io.File;
import java.io.IOException;

import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;

public class JacksonTester {
   public static void main(String args[]){
   
      JacksonTester tester = new JacksonTester();
  
      try {
         Student student = new Student();
         student.setAge(10);
         student.setName("Mahesh");
         tester.writeJSON(student);

         Student student1 = tester.readJSON();
         System.out.println(student1);

      }
      catch (JsonParseException e) { e.printStackTrace(); }
      catch (JsonMappingException e) { e.printStackTrace(); }
      catch (IOException e) { e.printStackTrace(); }
   }

   private void writeJSON(Student student) throws JsonGenerationException,  JsonMappingException, IOException{
      ObjectMapper mapper = new ObjectMapper(); 
      mapper.writeValue(new File("student.json"), student);
   }

   private Student readJSON() throws JsonParseException, JsonMappingException, IOException{
      ObjectMapper mapper = new ObjectMapper();
      Student student = mapper.readValue(new File("student.json"), Student.class);
      return student;
   }
}

class Student {
   private String name;
   private int age;
 
   public Student(){}
 
   public String getName() {
      return name;
   }
 
   public void setName(String name) {
      this.name = name;
   }
 
   public int getAge() {
      return age;
   }
 
   public void setAge(int age) {
      this.age = age;
   }
 
   public String toString(){
      return "Student [ name: "+name+", age: "+ age+ " ]";
   } 
}

Verify the Result

Compile the classes using javac compiler as follows −

C:\Jackson_WORKSPACE>javac JacksonTester.java

Now execute the jacksonTester to see the result.

C:\Jackson_WORKSPACE>java JacksonTester

Verify the Output −

Student [ name: Mahesh, age: 10 ]