多线程学习总结（线程的创建）

淡淡的烟草味﹌ 2023-02-26 12:26 16阅读 0赞

### 线程创建的三种方式 ###

##### 1.继承Thread类 #####

public class Test07 { 
        public static void main(String[] args) { 
            new MyThread().start();
        }
    }
    class MyThread extends Thread{ 
        @Override
        public void run() { 
            super.run();
            System.out.println("11111");
        }
    }

##### 2.实现Runnable接口 #####

public class Test08 { 
        public static void main(String[] args) { 
            new Thread(new MyThread2()).start();
        }
    }
    class MyThread2 implements Runnable{ 
    
        @Override
        public void run() { 
            System.out.println("22222");
        }
    }

##### 3.实现Callable接口 #####

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##### 1.Thread()参数要放一个Runnable的一个实现类 #####

public Thread(Runnable target) { 
        init(null, target, "Thread-" + nextThreadNum(), 0);
    }

##### 2.RunnableFuture接口继承了Runnable接口 #####

public interface RunnableFuture<V> extends Runnable, Future<V> { 
        /** * Sets this Future to the result of its computation * unless it has been cancelled. */
        void run();
    }

##### 3.FutureTask实现了上边那个接口，而且它里边的构造方法可以传Callable #####

public class FutureTask<V> implements RunnableFuture<V> { 
    public FutureTask(Callable<V> callable) { 
        if (callable == null)
            throw new NullPointerException();
        this.callable = callable;
        this.state = NEW;       // ensure visibility of callable
    }
    }

##### 具体操作如下 #####

public class Test09 { 
        public static void main(String[] args) throws ExecutionException, InterruptedException { 
            MyThread3 myThread3 = new MyThread3();
            FutureTask<String> task = new FutureTask<>(myThread3);
            new Thread(task).start();
            String s = task.get();
            System.out.println(s);
        }
    }
    class MyThread3 implements Callable<String>{ 
    
        @Override
        public String call() throws Exception { 
            return "3333";
        }
    }

##### Callable 这里的泛型就是方法的返回类型，通过task.get()方法可以获得。而Runnable接口，没有返回类型 #####

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