diff --git a/day09/src/com/inmind/extends_constructor04/Demo07.java b/day09/src/com/inmind/extends_constructor04/Demo07.java
new file mode 100644
index 0000000..73b6856
--- /dev/null
+++ b/day09/src/com/inmind/extends_constructor04/Demo07.java
@@ -0,0 +1,13 @@
+package com.inmind.extends_constructor04;
+/*
+继承中构造方法的访问特点：
+1.创建子类对象时，一定会先调用父类的构造方法
+2.super调用父类的构造方法时，必须在子类构造方法的第一行
+3.super可以调用父类的有参，无参构造方法，但必须在子类构造方法的第一行调用
+ */
+public class Demo07 {
+    public static void main(String[] args) {
+        Zi zi = new Zi();
+        System.out.println("程序结束");
+    }
+}
diff --git a/day09/src/com/inmind/extends_constructor04/Fu.java b/day09/src/com/inmind/extends_constructor04/Fu.java
new file mode 100644
index 0000000..775847e
--- /dev/null
+++ b/day09/src/com/inmind/extends_constructor04/Fu.java
@@ -0,0 +1,14 @@
+package com.inmind.extends_constructor04;
+
+public class Fu {
+    int i;
+
+    /*public Fu(){
+        System.out.println("父类的无参构造执行了");
+    }*/
+
+    public Fu(int i){
+        this.i = i;
+        System.out.println("父类的有参构造执行了");
+    }
+}
diff --git a/day09/src/com/inmind/extends_constructor04/Zi.java b/day09/src/com/inmind/extends_constructor04/Zi.java
new file mode 100644
index 0000000..ea374d4
--- /dev/null
+++ b/day09/src/com/inmind/extends_constructor04/Zi.java
@@ -0,0 +1,10 @@
+package com.inmind.extends_constructor04;
+
+public class Zi extends Fu{
+
+    public Zi(){
+        //super();//如果没写super(),编译器会主动地在第一行主动添加
+        super(1);
+        System.out.println("子类的无参构造执行了");
+    }
+}