update book model and perform cupd operations in H2 database

1.在models中添加：

public static Finder<Integer,Book> find = new Finder<>(Book.class);      

2.在BooksController中：

//for all books
public Result index(){
//Set<Book> books = Book.allBooks();
List<Book> books = Book.find.all();//添加了此行
return ok(index.render(books)) ;
}      

3.在views的books中将開頭改為：

@(books:List[Book])      

4.在BooksController的中：

public Result save(){
Form<Book> bookForm = formFactory.form(Book.class).bindFromRequest();
Book book = bookForm.get();
//Book.add(book);
book.save();//修改點
return redirect(routes.BooksController.index());
}

将所有Book book = Book.findById(id);改為Book book = Book.find.byId(id);

在public Result update()中添加oldBook.update();

将Book.remove(book);改為book.delete();      

5.localhost:9000測試正常

到此paly項目之BookStoreApp的學習到了一段落，全程差不多是根據youtube中一個巴基斯坦小哥的視訊學習的，