Java实现父子线程共享数据的几种方法

public class SharedVariableExample {
    private static int sharedData = 0;

    public static void main(String[] args) {
        Thread parentThread = new Thread(() -> {
            // 修改共享数据
            sharedData = 10;
            System.out.println("Parent Thread set sharedData to " + sharedData);

            Thread childThread = new Thread(() -> {
                // 访问共享数据
                System.out.println("Child Thread sees sharedData as " + sharedData);
            });

            childThread.start();
        });

        parentThread.start();
    }
}

public class ThreadLocalExample {
    private static ThreadLocal<Integer> threadLocalData = ThreadLocal.withInitial(() -> 0);

    public static void main(String[] args) {
        threadLocalData.set(10);

        Thread childThread = new Thread(() -> {
            Integer data = threadLocalData.get();
            System.out.println("Child Thread sees threadLocalData as " + data);
        });

        childThread.start();
    }
}

public class SynchronizedExample {
    private static int sharedData = 0;

    public static void main(String[] args) {
        Object lock = new Object();

        Thread parentThread = new Thread(() -> {
            synchronized (lock) {
                sharedData = 10;
                System.out.println("Parent Thread set sharedData to " + sharedData);

                Thread childThread = new Thread(() -> {
                    synchronized (lock) {
                        System.out.println("Child Thread sees sharedData as " + sharedData);
                    }
                });

                childThread.start();
            }
        });

        parentThread.start();
    }
}

import java.util.concurrent.ConcurrentHashMap;

public class ConcurrentHashMapExample {
    private static ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();

    public static void main(String[] args) {
        map.put("sharedKey", 10);

        Thread parentThread = new Thread(() -> {
            System.out.println("Parent Thread set map value to " + map.get("sharedKey"));

            Thread childThread = new Thread(() -> {
                System.out.println("Child Thread sees map value as " + map.get("sharedKey"));
            });

            childThread.start();
        });

        parentThread.start();
    }
}

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class ExecutorServiceExample {
    public static void main(String[] args) throws InterruptedException, ExecutionException {
        ExecutorService executor = Executors.newFixedThreadPool(2);

        Future<Integer> future = executor.submit(() -> {
            return 10; // 子线程返回数据
        });

        Integer result = future.get(); // 获取子线程返回的数据
        System.out.println("Main Thread received result: " + result);

        executor.shutdown();
    }
}