Java多线程解决private对象逸出-工厂模式(解决对象还未初始化完成就对外暴露)

叁歲伎倆 2022-12-03 09:18 95阅读 0赞

### 文章目录 ###

*   *   *  工厂模式

### 工厂模式 ###

使用工厂模式 ,对象一旦发布就是一个完整的对象,  
修复之前如下的文章中, 使用监听器,对象未完成初始化就把对象提供给外界  
[https://javaweixin6.blog.csdn.net/article/details/108350767][https_javaweixin6.blog.csdn.net_article_details_108350767]

构造方法使用private , 这样其他的对象不能调用构造方法.  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMjI5NjY5_size_16_color_FFFFFF_t_70_pic_center][]  
创建此工厂方法, 完成了初始化之后, 再进行注册  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMjI5NjY5_size_16_color_FFFFFF_t_70_pic_center 1][]  
main方法修改如下 :  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMjI5NjY5_size_16_color_FFFFFF_t_70_pic_center 2][]

完整的代码如下:

package com.thread.background;
    
    /** * 类名称:FactoryDesignFixListener * 类描述: 工厂模式修复监听器的对象还未初始化完成就对外发布 * * @author: https://javaweixin6.blog.csdn.net/ * 创建时间:2020/9/2 22:13 * Version 1.0 */
    public class FactoryDesignFixListener { 
    
        int count;
    
        private EventListener listener;
    
        private FactoryDesignFixListener(FactoryDesignFixListener.MySource source) { 
            //匿名内部类的方式 , 创建 EventListener接口实例
            listener = new EventListener() { 
                @Override
                public void onEvent(Event e) { 
                    //监听器, 监听到东西的时候, 就打印获取的值
                    System.out.println("\n我得到的数字是 " + count);
                }
            };
    
            //模拟其他业务逻辑
            for (int i = 0; i < 10000; i++) { 
                System.out.print(i);
            }
    
            //count初始化
            count = 100;
        }
    
        /** * 工厂模式方法 * * @param source * @return */
        public static FactoryDesignFixListener getInstance(MySource source) { 
            FactoryDesignFixListener sageListener = new FactoryDesignFixListener(source);
    
            //完成了初始化之后, 再进行注册
            source.registerListener(sageListener.listener);
            return sageListener;
        }
    
    
        public static void main(String[] args) { 
            MySource mySource = new MySource();
            new Thread(() -> { 
                try { 
                    Thread.sleep(10);
                } catch (InterruptedException e) { 
                    e.printStackTrace();
                }
                FactoryDesignFixListener instance = FactoryDesignFixListener.getInstance(mySource);
                mySource.eventCome(new FactoryDesignFixListener.Event() { 
    
                });
            }).start();
            FactoryDesignFixListener instance = FactoryDesignFixListener.getInstance(mySource);
        }
    
        static class MySource { 
    
            private FactoryDesignFixListener.EventListener listener;
    
            void registerListener(FactoryDesignFixListener.EventListener eventListener) { 
                this.listener = eventListener;
            }
    
            /** * 每次有事件来临的时候, 触发eventCome方法 * * @param e */
            void eventCome(FactoryDesignFixListener.Event e) { 
                if (listener != null) { 
                    listener.onEvent(e);
                } else { 
                    System.out.println("还未初始化完毕! ");
                }
            }
    
        }
    
        interface EventListener { 
            void onEvent(FactoryDesignFixListener.Event e);
        }
    
        interface Event { 
    
        }
    
    }

运行程序打印如下, 得到的是100 . 而之前由于已经隐含的暴露了外部类的对象,得到的是0 .  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMjI5NjY5_size_16_color_FFFFFF_t_70_pic_center 3][]

[https_javaweixin6.blog.csdn.net_article_details_108350767]: https://javaweixin6.blog.csdn.net/article/details/108350767
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMjI5NjY5_size_16_color_FFFFFF_t_70_pic_center 1]: /images/20221123/a553866b0f5449e6841b1be9fc95d723.png
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