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
1531476154573
name：myname    password:mypassword
1531476164574