update

code/src/main/java/com/raorao/java/oop/Children.java

@@ -0,0 +1,17 @@
+package com.raorao.java.oop;
+
+/**
+ * 子类.
+ *
+ * @author Xiong Raorao
+ * @since 2018-09-06-9:27
+ */
+public class Children extends Father {
+
+  int sum = 2;
+  int chlid = 3;
+
+  public void say() {
+    System.out.println("this is children say!");
+  }
+}

code/src/main/java/com/raorao/java/oop/Client.java

@@ -0,0 +1,16 @@
+package com.raorao.java.oop;
+
+/**
+ * 测试.
+ *
+ * @author Xiong Raorao
+ * @since 2018-09-06-9:28
+ */
+public class Client {
+
+  public static void main(String[] args) {
+    Father f = new Children();
+    System.out.println(f.num);
+    f.say();
+  }
+}

code/src/main/java/com/raorao/java/oop/Father.java

@@ -0,0 +1,16 @@
+package com.raorao.java.oop;
+
+/**
+ * 父类.
+ *
+ * @author Xiong Raorao
+ * @since 2018-09-06-9:26
+ */
+public class Father {
+  int num = 1;
+  public void say(){
+    System.out.println("this is father say!");
+  }
+}
+
+