一.小结
工厂模式用于创建具有相同属性的产品的一种方式。根据产品是具体产品还是具体工厂可分为简单工厂模式和工厂方法模式，根据工厂的抽象程度可分为工厂方法模式和抽象工厂模式。
二.简单工厂模式
简单工厂模式通用UML图如下：
下面以一个书籍的分类来说明：
public interface IBook {
String
content();
}
public class Novel implements IBook {
@Override
public String
content() {
return "小说";
}
}
public class Biography implements IBook {
@Override
public String
content() {
return "传记";
}
}
public final class BookFactory {
private BookFactory() {
}
public static IBook
getBook(Class
<? extends IBook> bookCls
) {
IBook book
= null
;
try {
book
= bookCls
.getDeclaredConstructor().newInstance();
} catch (Exception e
) {
e
.printStackTrace();
}
return book
;
}
}
public class Client {
public static void main(String
[] args
) {
IBook book
= BookFactory
.getBook(Novel
.class);
System
.out
.println("Book: " + book
.content());
}
}
三.工厂方法模式
public interface AbstractBookFactory {
IBook
getBook();
}
public class NovelFactory implements AbstractBookFactory {
@Override
public IBook
getBook() {
return new Novel();
}
}
public class BiographyFactory implements AbstractBookFactory {
@Override
public IBook
getBook() {
return new Biography();
}
}
public final class FactoryBuilder {
private FactoryBuilder() {
}
public static Novel
getNovel() {
return (Novel
) new NovelFactory().getBook();
}
public static Biography
getBiography() {
return (Biography
) new BiographyFactory().getBook();
}
}
public class Client {
public static void main(String
[] args
) {
System
.out
.println(FactoryBuilder
.getBiography().content());
}
}
四.抽象工厂
public interface IFan {
String
like();
}
public class NovelFan implements IFan{
@Override
public String
like() {
return "小说书迷";
}
}
public class BiographyFan implements IFan{
@Override
public String
like() {
return "传记书迷";
}
}
public interface AbstractFactory {
IBook
getBook();
IFan
getFan();
}
public class NovelFactory implements AbstractFactory {
@Override
public IBook
getBook() {
return new Novel();
}
@Override
public IFan
getFan() {
return new NovelFan();
}
}
public class BiographyFactory implements AbstractFactory {
@Override
public IBook
getBook() {
return new Biography();
}
@Override
public IFan
getFan() {
return new BiographyFan();
}
}
public class Client {
public static void main(String
[] args
) {
BiographyFactory biographyFactory
= FactoryBuilder
.getBiographyFactory();
System
.out
.println(biographyFactory
.getBook().content() + " " + biographyFactory
.getFan().like());
}
}
