TIJ笔记：内部类的初始化

看编程思想有点时间了，看到了些在马士兵老师没有讲过的部分，所以打算记录一下

内部类的初始化：

.内部类的初始化和外部类的初始化略有不同，可以使用 外部类对象.new 内部类对象 创建内部类对象

 package com.github.hellxz.practice10_2_2;

 public class Outer {
     public String toString() {
         return "Outer class override toString() method";
     }
     class Inner{
         public String toString() {
             return "Inner class override toString() method";
         }
     }
     public static void main(String args[]) {
         //this is wrong way to create inner class instance
         //! Inner inner = new Outer.Inner();
         Outer outer = new Outer(); //create outer instance first ,cuz an inner instance must create on a outer instance
         Inner inner = outer.new Inner(); //create inner instance.
         //the declare type also can be Outer.Inner
         Outer.Inner inner2 = outer.new Inner();
     }
 }

内部类对象返回外部类对象的引用：

.使用 .this  在上边代码的基础上修改代码

 package com.github.hellxz.test;

 public class Outer {
     public String toString() {
         return "Outer class override toString() method";
     }
     class Inner{
         //a method to return outer class reference
         Outer outer() {
             return Outer.this;
         }
         public String toString() {
             return "Inner class override toString() method";
         }
     }
     public static void main(String args[]) {
         Outer outer = new Outer();
         System.out.println(outer); //show which reference
         Inner inner = outer.new Inner();
         System.out.println(inner);
         // use inner class method to return outer class reference
         //! Inner inner2 = inner.outer(); //it wrong
         Outer outer2 = inner.outer();
         System.out.println(outer2);
     }
 }

 //output:
 //Outer class override toString() method
 //Inner class override toString() method
 //Outer class override toString() method

问我为啥注释都英文，因为我这linuxmint的root用户的fcitx好像没装好。在普通用户下正常，一使用root用户就不行，百度好久也没解决，有知道解决方法的老哥评论下告知呗，小弟感激不尽！