Springboot demo

Author.java

package books.entity;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@JsonIgnoreProperties(ignoreUnknown = true)
public class Author {

    private String firstName;
    private String lastName;

    public Author() {
    }

    public Author(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    @Override
    public String toString() {
        return "Author{" +
                "firstName='" + firstName + '\'' +
                ", lastName='" + lastName + '\'' +
                '}';
    }
}

Book.java

package books.entity;

public class Book {

    private String name;
    private String isbn;
    private int publishYear;
    private Author author;

    public Book() {
    }

    public Book(String name, String isbn, int publishYear, Author author) {
        this.name = name;
        this.isbn = isbn;
        this.publishYear = publishYear;
        this.author = author;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getIsbn() {
        return isbn;
    }

    public void setIsbn(String isbn) {
        this.isbn = isbn;
    }

    public int getPublishYear() {
        return publishYear;
    }

    public void setPublishYear(int publishYear) {
        this.publishYear = publishYear;
    }

    public Author getAuthor() {
        return author;
    }

    public void setAuthor(Author author) {
        this.author = author;
    }

    @Override
    public String toString() {
        return "Book{" +
                "name='" + name + '\'' +
                ", isbn='" + isbn + '\'' +
                ", publishYear=" + publishYear +
                ", author=" + author +
                '}';
    }
}

BookRepository.java

package books;

import books.entity.Author;
import books.entity.Book;

import java.util.ArrayList;
import java.util.List;

public class BookRepository {

    private List<Book> books;

    public BookRepository() {
        books = new ArrayList<Book>();
        initializeSampleData();
    }

    private void initializeSampleData() {
        books.add(new Book("Kmotr", "80-242-1102-5", 1969, new Author("Mario", "Puzo")));
        books.add(new Book("Omerta", "80-242-1642-6", 2000, new Author("Mario", "Puzo")));
        books.add(new Book("Inferno", "978-80-257-0934-4", 2013, new Author("Dan", "Brown")));
        books.add(new Book("Stoletý stařík, který vylezl z okna a zmizel", "978-80-87697-00-9", 2009, new Author("Jonas", "Jonasson")));
        books.add(new Book("Digitální pevnost", "80-86518-95-7", 1998, new Author("Dan", "Brown")));
        books.add(new Book("Modrá sféra", "80-7303-047-0", 2001, new Author("Jeffery", "Deaver")));
    }

    public List<Book> findAll() {
        return books;
    }

    public Book findByIsbn(String isbn) {
        return books.stream()
                .filter(book -> book.getIsbn().equals(isbn))
                .findFirst().orElse(null);
    }

    public Book add(Book book) {
        boolean exist = findByIsbn(book.getIsbn()) != null;
        if (exist)
            throw new RuntimeException("Books exist - ISBN: " + book.getIsbn());

        books.add(book);
        return book;
    }

    public Book remove(String isbn) {
        Book book = findByIsbn(isbn);
        if (book != null) {
            books.remove(book);
            return book;
        }

        throw new RuntimeException("Books doesn't exist - ISBN: " + book.getIsbn());
    }

    public Book update(String isbn, Book changes) {
        Book currentBook = findByIsbn(isbn);
        if (currentBook == null) {
            throw new RuntimeException("Books doesn't exist - ISBN: " + isbn);
        }

        if (!isbn.equals(changes.getIsbn()) && findByIsbn(changes.getIsbn()) != null) {
            throw new RuntimeException("Duplicate book - ISBN: " + isbn);
        }

        currentBook.setIsbn(changes.getIsbn());
        currentBook.setName(changes.getName());
        currentBook.setPublishYear(changes.getPublishYear());
        currentBook.setAuthor(changes.getAuthor());
        return currentBook;
    }
}

BooksController.java

package books;

import books.entity.Book;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import java.util.Collection;

@Controller
@EnableAutoConfiguration
public class BooksController {

    private final BookRepository bookRepository;

    public BooksController() {
        this.bookRepository = new BookRepository();
    }

    @ResponseBody
    @RequestMapping(value = "/books", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
    public Collection<Book> getAll() {
        return bookRepository.findAll();
    }

    @ResponseBody
    @RequestMapping(value = "/books/{isbn}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
    public Book findByIsbn(@PathVariable String isbn) {
        return bookRepository.findByIsbn(isbn);
    }

    @ResponseBody
    @RequestMapping(value = "/books/", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE)
    public Book add(@RequestBody Book book) {
        return bookRepository.add(book);
    }

    @ResponseBody
    @RequestMapping(value = "/books/{isbn}", method = RequestMethod.PUT, produces = MediaType.APPLICATION_JSON_VALUE)
    public Book update(@PathVariable String isbn, @RequestBody Book book) {
        return bookRepository.update(isbn, book);
    }


    @ResponseBody
    @RequestMapping(value = "/books/{isbn}", method = RequestMethod.DELETE, produces = MediaType.APPLICATION_JSON_VALUE)
    public Book remove(@PathVariable String isbn) {
        return bookRepository.remove(isbn);
    }


    public static void main(String[] args) {
        SpringApplication.run(BooksController.class, args);
    }
}

RestClientDemo.java

package exchangesrates;

import com.amazonaws.util.json.JSONException;
import com.amazonaws.util.json.JSONObject;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class RestClientDemo {

    // http://fixer.io/

    public static void main(String[] args) throws IOException, JSONException {
        // console();
        entity();
    }

    private static void entity() throws IOException, JSONException {
        HttpClient client = new DefaultHttpClient();
        HttpGet request = new HttpGet("http://api.fixer.io/latest");
        HttpResponse response = client.execute(request);
        BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

        StringBuffer result = new StringBuffer();
        String line = "";
        while ((line = rd.readLine()) != null) {
            result.append(line);
        }

        JSONObject json = new JSONObject(result.toString());
        System.out.println(json);
    }

    public static void console() throws IOException {
        HttpClient client = new DefaultHttpClient();
        HttpGet request = new HttpGet("http://api.fixer.io/latest");
        HttpResponse response = client.execute(request);
        BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        String line = "";
        while ((line = rd.readLine()) != null) {
            System.out.println(line);
        }
    }
}

SampleController.java

import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.stereotype.*;
import org.springframework.web.bind.annotation.*;

@Controller
@EnableAutoConfiguration
public class SampleController {

    @RequestMapping("/")
    @ResponseBody
    String home() {
        return "Hello World!";
    }

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SampleController.class, args);
    }
}