ThreadLocal类，实例测试，FutureTask类，实例测试。

1：测试ThreadLocal类, 为每个线程域保存局部变量。例如下面的例子。

ThreadLocal为每个线程保存了一个Test对象，那么当执行线程时，每个线程中的test具有唯一性。某一个线程执行时，查询当前线程是否在ThreadLocalMap是否具有Test缓存对像，判断出该线程具有ThreadLocal保存的Test对象时，就不再创建Test对象，使用ThreadLocal为本线程保存的Test对象。如果没有就创建一个。

package chapter03;

import java.util.concurrent.Executor;

import java.util.concurrent.ThreadPoolExecutor;

/**

 * @program: GradleTestUseSubModule

 * @author: Yafei Li

 * @create: 2018-07-12 16:14

 **/

public class ThreadLocalTest {

    static ThreadLocal<Test> threadLocal=new ThreadLocal(){

        public Test initialValue() {

            return new Test();

        }

    };

    public static void main(String[] args){

        Thread thread = new Thread(new Runnable() {

            @Override

            public void run() {

                while (true) {

                    Test test = threadLocal.get();

                    test.countplus();

                    System.out.println(Thread.currentThread()+"  "+test.i);

                    if (test.i > 5) {

                        break;

                    }

                }

            }

        });

        Thread thread2 = new Thread(new Runnable() {

            @Override

            public void run() {

                while (true) {

                    Test test = threadLocal.get();

                    test.countplus();

                    System.out.println(Thread.currentThread()+"  "+test.i);

                    if (test.i > 5) {

                        break;

                    }

                }

            }

        });

        thread.start();

        thread2.start();

        /**

         * 结果

         Thread[Thread-0,5,main]  1

         Thread[Thread-1,5,main]  1

         Thread[Thread-1,5,main]  2

         Thread[Thread-1,5,main]  3

         Thread[Thread-1,5,main]  4

         Thread[Thread-1,5,main]  5

         Thread[Thread-1,5,main]  6

         Thread[Thread-0,5,main]  2

         Thread[Thread-0,5,main]  3

         Thread[Thread-0,5,main]  4

         Thread[Thread-0,5,main]  5

         Thread[Thread-0,5,main]  6

         */

    }

}

class Test{

    int i=0;

    public void countplus() {

        i++;

    }

}

2：FutureTask表示线程一个将来的结果，方法会等到该线程得到结果为止。

例如：

package chapter05.class5;

import org.junit.Test;

import java.util.concurrent.Callable;

import java.util.concurrent.FutureTask;

/**

 * @program: GradleTestUseSubModule

 * @author: Yafei Li

 * @create: 2018-07-13 17:24

 **/

public class MyPreloader {

    //FutureTask 异步结果，闭锁

    private final FutureTask<ProductInfo> future = new FutureTask<ProductInfo>(new Callable<ProductInfo>() {

        @Override

        public ProductInfo call() throws Exception {

            System.out.println("执行thread中的future");

            System.out.println(System.currentTimeMillis());

            Thread.sleep(10000);

            ProductInfo productInfo=new ProductInfo("myname","mypassword");

            return productInfo;

        }

    });

    private final Thread thread = new Thread(future);  //FutureTask实现了Runnable类。

    public void start(){

        thread.start();

    }

    public ProductInfo get() {

        try {

            return future.get();  //会等待线程执行，直到返回结果。

        }catch (Exception e){

            e.printStackTrace();

        }

        return null;

    }

    @Test

    public void test() {

        thread.start();  //执行thread，得到FutureTask

        ProductInfo productInfo=get();  //会等待线程执行，直到得到返回的结果

        System.out.println("name："+productInfo.getName()+"    password:"+productInfo.getPassword());

        System.out.println(System.currentTimeMillis());

    }

}

ProductInfo类

package chapter05.class5;

public class ProductInfo {

    private String name;

    private String password;

    public ProductInfo(String name, String password) {

        this.name = name;

        this.password = password;

    }

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

}

结果：

执行thread中的future

153147614573

name：myname    password:mypassword

153147614574

巴特西

ThreadLocal类，实例测试，FutureTask类，实例测试。

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