Jackson - Enlace de datos completo

El enlace de datos completo se refiere al mapeo de JSON a cualquier objeto JAVA.

//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);

Veamos el enlace de datos simple en acción. Aquí asignaremos el objeto JAVA directamente a JSON y viceversa.

Cree un archivo de clase java llamado JacksonTester en C:\>Jackson_WORKSPACE.

Archivo: JacksonTester.java

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

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

Compila las clases usando javac compilador de la siguiente manera:

C:\Jackson_WORKSPACE>javac JacksonTester.java

Ahora ejecute el jacksonTester para ver el resultado:

C:\Jackson_WORKSPACE>java JacksonTester

Verificar la salida

Student [ name: Mahesh, age: 10 ]

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