Spring Boot MongoDB get only certain fields from database into model - spring

Question

I am trying to understand how to work with MongoDB and Spring Boot. I have a mongodb with sample data and I want it to return only selected fields and not the entire data.
My mongoDB collection contains data in the format
DAO.java
package com.books.Reading.DAO;
import com.books.Reading.model.booksModel;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.data.mongodb.repository.Query;
public interface readingListDAO extends MongoRepository<booksModel, String> {
#Query("{'title' : 'Griffon in Action'}")
public booksModel findFirstByOrderByTitleAsc();
}
model.java
package com.books.Reading.model;
import org.springframework.data.mongodb.core.mapping.Document;
#Document
public class booksModel {
String title;
String isbn;
int pageCount;
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getIsbn() {
return isbn;
}
public void setIsbn(String isbn) {
this.isbn = isbn;
}
public int getPageCount() {
return pageCount;
}
public void setPageCount(int pageCount) {
this.pageCount = pageCount;
}
}
controller.java
package com.books.Reading.controller;
import com.books.Reading.model.booksModel;
import com.books.Reading.service.readingListService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class readingListController {
#Autowired
private readingListService rlService;
#RequestMapping("/")
#ResponseBody
public booksModel getOne(){
return rlService.getOne();
}
}
service.java
package com.books.Reading.service;
import com.books.Reading.model.booksModel;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
#Service
public class readingListService {
#Autowired
private com.books.Reading.DAO.readingListDAO readingListDAO;
public booksModel getOne(){
System.out.println(readingListDAO.findFirstByOrderByTitleAsc());
return readingListDAO.findFirstByOrderByTitleAsc();
}
}
application.properties
spring.data.mongodb.host=127.0.0.1
spring.data.mongodb.port=27017
spring.data.mongodb.database=book
spring.session.mongodb.collection-name=readinglist
The MongoDB is hosted locally. How can I retrieve only selected fields (title, isbn and pageCount) from the database.
I am very new to Spring Boot, so if there are other errors or best practices, I welcome your feedback.

Answer 1

By default, all the properties of document will be fetched. if you want to ignore some of the properties in the result, you can use filter option.
#Query(value = "{'title' : ?0}", fields = "{'description' : 0}")
BooksModel findBooksModelByTitle(String title);