Converting an Object to/from JSON using GSON (Google API)

Converting an Object to/from JSON using GSON (Google API)

Maven dependency required :

<dependency>

         <groupId>com.google.code.gson</groupId>

         <artifactId>gson</artifactId>

         <version>1.7.1</version>

  </dependency>

DataObject class

public class DataObject {

      private int data1 = 100;

      private int data2 = 200;

      List<String> list = new ArrayList<String>() {

            private static final long serialVersionUID = 1L;

            {

                  add("String 1");

                  add("String 2");

                  add("String 3");

            }

      };

      public String toString() {

            return "DataObject [data1=" + data1 + ", data2=" + data2 + ", list="

                        + list + "]";

      }

}

Class converting Object to/from JSON

public class ObjectToFromJson {

      public static void toJson() {

            DataObject obj = new DataObject();

            Gson gson = new Gson();

            // convert java object to JSON format,

            // and returned as JSON formatted string

            String json = gson.toJson(obj);

            System.out.println(json);

            try {

                  // write converted json data to a file named "file.json"

                  FileWriter writer = new FileWriter("C://workspace//DataStructure//GJson//file.json");

                  writer.write(json);

                  writer.close();

            } catch (IOException e) {

                  e.printStackTrace();

            }

      }

     

      public static void fromJson() {

            Gson gson = new Gson();

            try {

                  BufferedReader br = new BufferedReader(new FileReader(

                              "C://workspace//DataStructure//GJson//file.json"));

                  // convert the json string back to object

                  DataObject obj = gson.fromJson(br, DataObject.class);

                  System.out.println(obj);

            } catch (IOException e) {

                  e.printStackTrace();

            }

      }

     

      public static void main(String[] args) {

            toJson();

            fromJson();

      }

}

Output :

{"data1":100,"data2":200,"list":["String 1","String 2","String 3"]}

DataObject [data1=100, data2=200, list=[String 1, String 2, String 3]]