Java8 - 自定义实现体会Future的原理

绝地灬酷狼 2022-10-22 07:40 135阅读 0赞

### 文章目录 ###

*  自定义Future
 *  
 *  
 *  同步方式

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70]

--------------------

# 自定义Future #

package com.artisan.java8.testFuture.customFuture;
    
    public interface CustomFutureInterface<T> { 
    
    
        T get();
    
        Boolean isFinished();
    
    }

#  #

package com.artisan.java8.testFuture.customFuture;
    
    public interface CustomCallable<T> { 
    
        T doAction();
    }

#  #

package com.artisan.java8.testFuture.customFuture;
    
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.atomic.AtomicBoolean;
    import java.util.concurrent.atomic.AtomicReference;
    
    /** * @author 小工匠 * @version 1.0 * @description: TODO * @date 2021/4/5 9:40 * @mark: show me the code , change the world */
    public class CustomFutureTest<T> { 
    
    
        public static <T> CustomFutureInterface<T> invoke(CustomCallable<T> callable){ 
    
            // 使用引用，传递结果
            AtomicReference<T> result = new AtomicReference<>();
            AtomicBoolean isDone = new AtomicBoolean(false);
    
            // 开启子线程，执行异步任务
            new Thread(()->{ 
                T t = callable.doAction();
                // 在子线程中将结果封装到原子类中，便于其他线程获取
                result.set(t);
                isDone.set(true);
    
            }).start();
    
    
           
            CustomFutureInterface<T> tCustomFutureInterface = new CustomFutureInterface<T>() { 
                @Override
                public T get() { 
                    return result.get();
                }
    
                @Override
                public Boolean isFinished() { 
                    return isDone.get();
                }
            } ;
            return tCustomFutureInterface;
        }
    
        public static void main(String[] args) { 
    
            CustomFutureInterface<String> invoke = invoke(() -> { 
                try { 
                    TimeUnit.SECONDS.sleep(5);
                } catch (InterruptedException e) { 
                    return "I'm Error";
    
                }
                return "I'm value";
            });
    
    
            System.out.println("获取子线程的返回结果: " + invoke.get());
    
            while(!invoke.isFinished()){ 
    
                try { 
                    System.out.println("子线程 没有结束，休眠1S...");
                    TimeUnit.SECONDS.sleep(1);
                } catch (InterruptedException e) { 
                    e.printStackTrace();
                }
            }
    
    
            System.out.println("子线程执行结束了，获取子线程的返回结果..."  + invoke.get());
    
        }
    
    
    
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70 1]

--------------------

# 同步方式 #

为了对比下，我们来看下同步的方式

/** * 同步阻塞方法 * @param callable * @param <T> * @return */
        public static <T>  T block(CustomCallable<T> callable){ 
            return callable.doAction();
        }

调用测试

System.out.println(" ");
    
            System.out.println("同步测试ing...............start");
            long begin = System.currentTimeMillis();
            //测试同步
            String result = block(
                    () -> { 
                        { 
                            try { 
                                TimeUnit.SECONDS.sleep(5);
                            } catch (InterruptedException e) { 
                                return "I'm Error";
                            }
                            return "I'm value sync";
                        }
                    });
            System.out.println("同步测试ing...............end cost " + (System.currentTimeMillis() - begin));
    
            System.out.println("返回结果: " + result);

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70_pic_center]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70]: /images/20221022/90b28bd4bcce4b6582b28787a4393f8f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70 1]: /images/20221022/d9d7df79cfc34e608dd5ec9f166ba366.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70 2]: /images/20221022/c977850de9064ad583c4e81e87882355.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70_pic_center]: /images/20221022/4b6f67cd7dd443248ac581e8f150c67c.png