浅谈Java获得多线程的返回结果方式(3种)

package com.test.thread;

import java.util.*;
import sun.swing.AccumulativeRunnable;
//获得线程的返回结果方式一
/*
 *在runnable实现类中设置一个变量x,在run方法中将其改变为我们期待的结果，然后通过一个getX()方法将这个变量返回 
 */
public class RunnableTest {
 public static void main(String[] args) throws Exception {
  System.out.println("使用Runnable获取返回结果");
  List<Thread> workers = new ArrayList<>(10);
  List<RunnableAcction> tasks = new ArrayList<>(10);
  //创建10个线程，每个线程分别负责累加1-10,11-20，.........，91-100
  for(int i=0;i<10;i++) {
  RunnableAcction task = new RunnableAcction(i*10+1,(i+1)*10);
  Thread work = new Thread(task,"累加器线程"+i);
  workers.add(work);
  tasks.add(task);
  work.start();
  }
  int total = 0;
  for(int i = 0;i<workers.size();i++) {
  workers.get(i).join();
  total += tasks.get(i).getResult();
  }
  System.out.println("\n累加的结果："+total);
 }
 
 static final class RunnableAcction implements Runnable{
  
  private int a;
  public RunnableAcction(int a, int b) {
  super();
  this.a = a;
  this.b = b;
  }
  private int b;
  private int result; 
  @Override
  public void run() {
  result = 0;
  try {
   for(int i=a;i<= b;i++) {
   result += i;
   Thread.sleep(100);
   }
  } catch (Exception e) {
   // TODO: handle exception
  }
  System.out.printf("(%s) - 运行结束，结果为 %d\n",Thread.currentThread().getName(),result);
  }
    public int getResult() {//获取线程返回结果
       return result;
    }
 }
}

import java.util.*;
import java.util.concurrent.*;

public class CallableTest {

  public static void main(String[] args) throws Exception {
    System.out.println("使用 Callable 获得返回结果：");
    
    List<FutureTask<Integer>> futureTasks = new ArrayList<>(10);
    // 新建 10 个线程，每个线程分别负责累加 1~10, 11~20, ..., 91~100
    for (int i = 0; i < 10; i++) {
      AccumCallable task = new AccumCallable(i * 10 + 1, (i + 1) * 10);
      FutureTask<Integer> futureTask = new FutureTask<>(task);
      futureTasks.add(futureTask);
      Thread worker = new Thread(futureTask, "慢速累加器线程" + i);
      worker.start();
    }

    int total = 0;
    for (FutureTask<Integer> futureTask : futureTasks) {
      total += futureTask.get(); // get() 方法会阻塞直到获得结果
    }
    System.out.println("累加的结果: " + total);
  }

  static final class AccumCallable implements Callable<Integer> {

    private final int begin;
    private final int end;

    public AccumCallable(int begin, int end) {
      this.begin = begin;
      this.end = end;
    }

    @Override
    public Integer call() throws Exception {
      int result = 0;
      for (int i = begin; i <= end; i++) {
        result += i;
        Thread.sleep(100);
      }
      System.out.printf("(%s) - 运行结束，结果为 %d\n",
      Thread.currentThread().getName(), result);
      return result;
    }
  } 
}

import java.util.*;
import java.util.concurrent.*;

public class FutureTest1 {

  public static void main(String[] args) {
  
    Task task = new Task();// 新建异步任务,然后执行futureTask
    FutureTask<Integer> future = new FutureTask<Integer>(task) {
      // 异步任务执行完成，回调
      @Override
      protected void done() {
        try {
          System.out.println("future.done():" + get());
        } catch (InterruptedException e) {
          e.printStackTrace();
        } catch (ExecutionException e) {
          e.printStackTrace();
        }
      }
    };
    // 创建线程池（使用了预定义的配置）
    ExecutorService executor = Executors.newCachedThreadPool();
    executor.execute(future);

    try {
      Thread.sleep(1000);
    } catch (InterruptedException e1) {
      e1.printStackTrace();
    }
    // 可以取消异步任务
    // future.cancel(true);

    try {
      // 阻塞，等待异步任务执行完毕-获取异步任务的返回值
      System.out.println("future.get():" + future.get());
    } catch (InterruptedException e) {
      e.printStackTrace();
    } catch (ExecutionException e) {
      e.printStackTrace();
    }
  }

  // 异步任务
  static class Task implements Callable<Integer> {
    // 返回异步任务的执行结果
    @Override
    public Integer call() throws Exception {
      int i = 0;
      for (; i < 10; i++) {
        try {
          System.out.println("异步任务："+Thread.currentThread().getName() + "_"              + i);
          Thread.sleep(500);
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
      }
      return i;
    }
  }
}