简单工厂

src/main/java/top/fjy8018/designpattern/pattern/creational/simplefactory/AbstractVideo.java

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+package top.fjy8018.designpattern.pattern.creational.simplefactory;
+
+/**
+ * 简单工厂
+ *
+ * @author F嘉阳
+ * @date 2018-09-23 16:13
+ */
+public abstract class AbstractVideo {
+    public abstract void produce();
+}

src/main/java/top/fjy8018/designpattern/pattern/creational/simplefactory/JavaAbstractVideo.java

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+package top.fjy8018.designpattern.pattern.creational.simplefactory;
+
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * @author F嘉阳
+ * @date 2018-09-23 16:13
+ */
+@Slf4j
+public class JavaAbstractVideo extends AbstractVideo {
+    @Override
+    public void produce() {
+        log.info("生产Java视频");
+    }
+}

src/main/java/top/fjy8018/designpattern/pattern/creational/simplefactory/PythonAbstractVideo.java

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+package top.fjy8018.designpattern.pattern.creational.simplefactory;
+
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * @author F嘉阳
+ * @date 2018-09-23 16:14
+ */
+@Slf4j
+public class PythonAbstractVideo extends AbstractVideo {
+    @Override
+    public void produce() {
+        log.info("生产Python视频");
+    }
+}

src/main/java/top/fjy8018/designpattern/pattern/creational/simplefactory/VideoFactory.java

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+package top.fjy8018.designpattern.pattern.creational.simplefactory;
+
+/**
+ * @author F嘉阳
+ * @date 2018-09-23 16:16
+ */
+public class VideoFactory {
+
+    /**
+     * 由工厂负责创建类，业务层无需关心具体实现
+     * 其缺点是不符合开闭原则，即如果具体实现类扩展后，工厂类也必须修改
+     *
+     * @param type
+     * @return
+     */
+    public AbstractVideo getVideo(String type) {
+        switch (type) {
+            case "Java":
+                return new JavaAbstractVideo();
+            case "Python":
+                return new PythonAbstractVideo();
+            default:
+                return null;
+        }
+    }
+
+    /**
+     * 通过反射在一定程度弥补简单工厂不足（开闭原则）
+     *
+     * @param c
+     * @return
+     */
+    public AbstractVideo getVideo(Class c) {
+        AbstractVideo video = null;
+        try {
+            video = (AbstractVideo) Class.forName(c.getName()).newInstance();
+        } catch (ClassNotFoundException | IllegalAccessException | InstantiationException e) {
+            e.printStackTrace();
+        }
+        return video;
+    }
+}

src/test/java/top/fjy8018/designpattern/pattern/creational/simplefactory/AbstractVideoTest.java

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+package top.fjy8018.designpattern.pattern.creational.simplefactory;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class AbstractVideoTest {
+
+    /**
+     * 不使用简单工厂，则业务层需要引入具体的实现类
+     */
+    @Test
+    void before() {
+        AbstractVideo video = new JavaAbstractVideo();
+        video.produce();
+    }
+
+    /**
+     * 使用简单工厂后业务层无需导入具体的实现类，即不关心具体实现过程
+     */
+    @Test
+    void after() {
+        VideoFactory factory = new VideoFactory();
+        AbstractVideo video = factory.getVideo("Java");
+        video.produce();
+    }
+
+    /**
+     * 通过传递类名方式改进扩展性问题
+     */
+    @Test
+    void improve() {
+        VideoFactory factory = new VideoFactory();
+        AbstractVideo video = factory.getVideo(JavaAbstractVideo.class);
+        video.produce();
+    }
+}