Jackson - Full Data Binding


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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 ]

jackson_data_binding.htm

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