上传文件至 'w5 Shape'

w5 Shape/Circle.java

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+public class Circle extends Shape {
+	@Override
+	public void draw() {
+		System.out.println("绘制一个圆形");
+	}
+}

w5 Shape/Rectangle.java

@@ -0,0 +1,6 @@
+public class Rectangle extends Shape {
+	@Override
+	public void draw() {
+		System.out.println("绘制一个矩形");
+	}
+}

w5 Shape/Shape.java

@@ -0,0 +1,5 @@
+public class Shape {
+	public void draw() {
+		System.out.println("绘制一个形状");
+	}
+}

w5 Shape/TestShape.java

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+public class TestShape {
+
+	public static void drawShape(Shape s) {
+		s.draw();
+	}
+
+	public static void main(String[] args) {
+		Shape shape = new Shape();
+		Circle circle = new Circle();
+		Rectangle rectangle = new Rectangle();
+		drawShape(shape);
+		drawShape(circle);
+		drawShape(rectangle);
+	}
+}