refactor

school/Staff.java

@@ -0,0 +1,23 @@
+package school;
+
+public class Staff extends Person {
+    private String staffID;
+
+    public Staff(String name, int age, String staffID) {
+        super(name, age);
+        this.staffID = staffID;
+    }
+
+    public void speak() {
+        System.out.println("I am a staff, my name is " + getName() + ", and I am " + getAge()
+                + " years old. My staff ID is " + staffID + ".");
+    }
+
+    public String getStaffID() {
+        return staffID;
+    }
+
+    public void setStaffID(String staffID) {
+        this.staffID = staffID;
+    }
+}