Add ShapeDemo.java in w5 folder

6/w5/ShapeDemo.java

@@ -0,0 +1,51 @@
+public class ShapeDemo {
+    public static void main(String[] args) {
+        // 创建不同形状的对象
+        Shape circle = new Circle();
+        Shape rectangle = new Rectangle();
+        
+        // 测试drawShape方法
+        drawShape(circle);
+        drawShape(rectangle);
+    }
+    
+    /**
+     * 调用形状的draw方法
+     * @param s 形状对象
+     */
+    public static void drawShape(Shape s) {
+        s.draw();
+    }
+}
+
+/**
+ * 形状基类
+ */
+class Shape {
+    /**
+     * 绘制方法
+     */
+    public void draw() {
+        System.out.println("绘制形状");
+    }
+}
+
+/**
+ * 圆形类
+ */
+class Circle extends Shape {
+    @Override
+    public void draw() {
+        System.out.println("绘制圆形");
+    }
+}
+
+/**
+ * 矩形类
+ */
+class Rectangle extends Shape {
+    @Override
+    public void draw() {
+        System.out.println("绘制矩形");
+    }
+}