设计模式二工厂方法模式：边学边做个生成电子书的工具（python+dart）

工厂方法模式定义一个用于创建对象的接口，让子类决定实例化哪一个类 ，使得一个类的实例化延迟到他的子类。

小工具的python 实现部分代码 markdown 直接贴的代码会乱，我还不懂如何调整，大家将就

highlight: a11y-dark

import abc
from abc import *

class BookInfo(object):
    url = ""
    navItemContent = ""
    content = ""

    def __init__(self, url, navItem, content):
        self.url = url
        self.navItemContent = navItem
        self.content = content




class ExportBook(metaclass=abc.ABCMeta):
    @abstractmethod
    def exportBookApi(self,book):
        pass



class ExportBookPdf(ExportBook):
    def __init__(self, book):
        pass
    def exportBookApi(self,book):
        print("export pdf file by ExportBookApi ")
        print(book.fileExtension)
        print(book.bookInfo.url)


class ExportBookMobi(ExportBook):
    def __init__(self, book):
        pass
    def exportBookApi(self,book):
        print("export mobi file by ExportBookApi")
        print(book.fileExtension)

class ExportBookHtml(ExportBook):
    def __init__(self, book):
        pass
    def exportBookApi(self,book):
        print("export html file by ExportBookApi")
        print(book.fileExtension)


class ExportBookOperate(ExportBook):
    @staticmethod
    def exportBookFactory(book):
        if isinstance(book, MobiBook):
            return ExportBookMobi(book)
        elif isinstance(book,PdfBook):
            return ExportBookPdf(book)
        elif isinstance(book,HtmlBook):
            return ExportBookHtml(book)
        else:
            print("其他格式暂不支持")


class Book(metaclass=abc.ABCMeta):
    bookInfo = ""
    fileExtension = ""
    name = ""


    def __init__(self, bookInfo, fmt):
        self.bookInfo = bookInfo
        self.fileExtension = "." + fmt
        self.name = self.calcBookName(fmt)
        self.prepare()

    @abstractmethod
    def makeBook(self):
        '''
        makeBook
        :制作电子书:
        '''

    def calcBookName(self, fmt):
        '''
        从参数里面计算出书的名字
        :return:
        '''
        print(self.bookInfo.url)
        filenameTempString = self.bookInfo.url.split("//")[1]
        filenameTempString = filenameTempString.replace(".", "_")
        filenameTempString = filenameTempString.replace("-", "_")
        filenameTempString = filenameTempString.replace("/", "_")
        file_name = filenameTempString + self.fileExtension

        return file_name

    def prepare(self):
        """
        准备工作
        :return:
        """
        # print(__doc__)
        print(self.name)


class PdfBook(Book):
    """
    pdf book
    """
    def makeBook(self):
        """
        make pdf book func
        :return:
        """
        print(PdfBook.__doc__)


class MobiBook(Book):
    """
    Mobi book
    """
    def makeBook(self):
        """
        make mobi book func
        :return:
        """
        print(MobiBook.__doc__)


class HtmlBook(Book):
    """html book """

    def makeBook(self):
        """
        make html book func
        :return:
        """
        print(HtmlBook.__doc__)


class SimpleFactory(object):
    """
    简单工厂
    """

    @staticmethod
    def createBook(bookInfo, fmt):
        """
        简单工厂
        :param bookInfo:
        :param fmt:
        :return:
        """

        if 'pdf' in fmt:
            print("create pdf factory")
            return PdfBook(bookInfo, fmt)
        elif "mobi" in fmt:
            print("create mobi file")
            return MobiBook(bookInfo, fmt)
        elif 'html' in fmt:
            print("create html file")
            return HtmlBook(bookInfo, fmt)
        else:
            print("暂时支持pdf 和mobi和html")


print("test now")
bookInfo = BookInfo("https://flutter.cn/docs", "nav_item", "content")
bookCreate = SimpleFactory.createBook(bookInfo, 'pdf')

bookExport = ExportBookOperate.exportBookFactory(bookCreate)
bookExport.exportBookApi(bookCreate)

运行结果截个图

dart 实现的代码

class BookInfo {
  String url = "";
  String content = "";
  String navItem = "";
  BookInfo(this.url, this.navItem, this.content);
}

class Book {
  BookInfo bookInfo;

  String fmt;

  Book(this.bookInfo, this.fmt) {
    print("init bookInfo");
  }

  makeBook() {
    print("make book" + fmt);
  }
}

class HtmlBook extends Book {
  HtmlBook(BookInfo bookInfo, String fmt) : super(bookInfo, fmt);

  @override
  makeBook() {
    print("html file  override xxxxxxxxxxxxxxxxxxxx");
    return super.makeBook();
  }
}

class PdfBook extends Book {
  PdfBook(BookInfo bookInfo, String fmt) : super(bookInfo, fmt);

  @override
  makeBook() {
    print("pdf file");
    return super.makeBook();
  }
}

class MobiBook extends Book {
  MobiBook(BookInfo bookInfo, String fmt) : super(bookInfo, fmt);
  @override
  makeBook() {
    print("mobi book");
    return super.makeBook();
  }
}

class SimpleFactory extends Object {
  static createBook(BookInfo bookInfo, String fmt) {
    if (fmt.endsWith("pdf")) {
      print(" pdf xxx");
      return PdfBook(bookInfo, fmt);
    } else if (fmt.endsWith("html")) {
      print(" html xxx");
      return HtmlBook(bookInfo, fmt);
    } else if (fmt.endsWith("mobi")) {
      print(" mobi xxx");
      return MobiBook(bookInfo, fmt);
    } else {
      print("不支持其他格式");
    }
  }
}

abstract class ExportBook {
  exportBookApi(Book book);
}

class ExportBookPdf extends ExportBook {
  ExportBookPdf(Book book);
  @override
  exportBookApi(Book book) {
    print("implement of export pdf file");
    print(book.fmt);
  }
}

class ExportBookHtml extends ExportBook {
  ExportBookHtml(Book book);
  @override
  exportBookApi(Book book) {
    print("implement of export html file");
    print(book.fmt);
  }
}

class ExportBookMobi extends ExportBook {
  ExportBookMobi(Book book);
  @override
  exportBookApi(Book book) {
    print("implement of export mobi file");
    print(book.fmt);
  }
}

class ExportBookFactory {
  static ExportBook? exportBookFactory(Book book) {
    try {
      if (book.runtimeType.toString() == "PdfBook") {
        print("pdf book factory");
        return ExportBookPdf(book);
      } else if (book.runtimeType.toString() == "HtmlBook") {
        print("html book factory");
        return ExportBookHtml(book);
      } else if (book.runtimeType.toString() == "MobiBook") {
        print("mobi book factory");
        return ExportBookMobi(book);
      }
    } catch (e) {
      print("$e");
    }
    return null;
  }
}

void main(List<String> args) {
  BookInfo bi = BookInfo("https://flutter.cn/docs", "nav_item", "content");

  Book thisBook = SimpleFactory.createBook(bi, "html");
  thisBook.makeBook();

  print("---------------------------------------");

  ExportBookFactory.exportBookFactory(thisBook)?.exportBookApi(thisBook);
}

运行结果