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);
Let's see simple data binding in action. Here we'll map 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 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
Compile the classes using javac compiler as follows:
C:\Jackson_WORKSPACE>javac JacksonTester.java
Now run the jacksonTester to see the result:
C:\Jackson_WORKSPACE>java JacksonTester
Verify the Output
Student [ name: Mahesh, age: 10 ]
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