@FunctionalInterface
public interface Callable<V> {
    V call() throws Exception;
}

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;

// 定義Callable實(shí)現(xiàn)類(lèi)
class MyCallable implements Callable<Integer> {
    @Override
    public Integer call() throws Exception {
        int sum = 0;
        for (int i = 1; i <= 100; i++) {
            sum += i;
        }
        return sum;
    }
}

public class CallableThreadExample {
    public static void main(String[] args) {
        // 創(chuàng)建Callable實(shí)例
        Callable<Integer> callable = new MyCallable();
        // 創(chuàng)建FutureTask實(shí)例，并將Callable實(shí)例作為參數(shù)傳入
        FutureTask<Integer> futureTask = new FutureTask<>(callable);
        // 創(chuàng)建Thread實(shí)例，并將FutureTask作為參數(shù)傳入
        Thread thread = new Thread(futureTask);
        // 啟動(dòng)線程
        thread.start();

        try {
            // 獲取Callable任務(wù)的執(zhí)行結(jié)果
            Integer result = futureTask.get();
            System.out.println("計(jì)算結(jié)果: " + result);
        } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
        }
    }
}

import java.util.concurrent.*;

class MyCallable2 implements Callable<String> {
    @Override
    public String call() throws Exception {
        Thread.sleep(2000);
        return "任務(wù)執(zhí)行完成";
    }
}

public class CallableThreadPoolExample {
    public static void main(String[] args) {
        // 創(chuàng)建線程池
        ExecutorService executorService = Executors.newFixedThreadPool(3);
        // 創(chuàng)建Callable實(shí)例
        Callable<String> callable = new MyCallable2();
        // 提交Callable任務(wù)，并返回Future對(duì)象
        Future<String> future = executorService.submit(callable);

        try {
            // 獲取任務(wù)執(zhí)行結(jié)果
            String result = future.get();
            System.out.println(result);
        } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
        } finally {
            // 關(guān)閉線程池
            executorService.shutdown();
        }
    }
}