书籍、类别和目录

package com.redislabs.edu.redi2read.boot;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.redislabs.edu.redi2read.models.Book;
import com.redislabs.edu.redi2read.models.Category;
import com.redislabs.edu.redi2read.repositories.BookRepository;
import com.redislabs.edu.redi2read.repositories.CategoryRepository;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

import lombok.extern.slf4j.Slf4j;

@Component
@Order(3)
@Slf4j
public class CreateBooks implements CommandLineRunner {
  @Autowired
  private BookRepository bookRepository;

  @Autowired
  private CategoryRepository categoryRepository;

  @Override
  public void run(String... args) throws Exception {
    if (bookRepository.count() == 0) {
    ObjectMapper mapper = new ObjectMapper();
    TypeReference<List<Book>> typeReference = new TypeReference<List<Book>>() {
    };

    List<File> files = //
        Files.list(Paths.get(getClass().getResource("/data/books").toURI())) //
            .filter(Files::isRegularFile) //
            .filter(path -> path.toString().endsWith(".json")) //
            .map(java.nio.file.Path::toFile) //
            .collect(Collectors.toList());

    Map<String, Category> categories = new HashMap<String, Category>();

    files.forEach(file -> {
          try {
            log.info(">>>> Processing Book File: " + file.getPath());
            String categoryName = file.getName().substring(0, file.getName().lastIndexOf("_"));
            log.info(">>>> Category: " + categoryName);

            Category category;
            if (!categories.containsKey(categoryName)) {
            category = Category.builder().name(categoryName).build();
            categoryRepository.save(category);
            categories.put(categoryName, category);
            } else {
            category = categories.get(categoryName);
            }

            InputStream inputStream = new FileInputStream(file);
            List<Book> books = mapper.readValue(inputStream, typeReference);
            books.stream().forEach((book) -> {
            book.addCategory(category);
            bookRepository.save(book);
            });
            log.info(">>>> " + books.size() + " Books Saved!");
          } catch (IOException e) {
            log.info("Unable to import books: " + e.getMessage());
          }
    });

    log.info(">>>> Loaded Book Data and Created books...");
    }
  }
}