Java开发：如何使用异步编程提高应用性能

import java.util.concurrent.*;

public class FutureDemo {
    public static void main(String[] args) throws InterruptedException, ExecutionException {
        ExecutorService executorService = Executors.newSingleThreadExecutor();

        // 提交任务并返回Future对象
        Future<String> future = executorService.submit(() -> {
            Thread.sleep(1000);
            return "异步任务执行结果";
        });

        // 执行其他操作
        System.out.println("执行其他操作...");

        // 获取异步任务结果（阻塞等待）
        String result = future.get();
        System.out.println("异步任务执行结果：" + result);

        // 关闭线程池
        executorService.shutdown();
    }
}

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

public class CompletableFutureDemo {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        // 使用CompletableFuture执行异步任务
        CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "异步任务执行结果";
        });

        // 执行其他操作
        System.out.println("执行其他操作...");

        // 异步任务返回结果后执行回调函数
        future.thenAccept(result -> {
            System.out.println("异步任务执行结果：" + result);
        });

        // 阻塞等待异步任务完成
        future.get();
    }
}

import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

@Service
public class AsyncService {
    @Async
    public void asyncMethod() {
        // 异步执行的方法逻辑
        // ...
    }
}

public class Main {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
        context.register(AsyncService.class);
        context.refresh();

        AsyncService asyncService = context.getBean(AsyncService.class);
        asyncService.asyncMethod();

        context.close();
    }
}

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;

public class NettyClient {
    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup group = new NioEventLoopGroup();

        try {
            Bootstrap bootstrap = new Bootstrap()
                    .group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new MyChannelInitializer());

            ChannelFuture future = bootstrap.connect("localhost", 8080).sync();

            // 异步发送数据
            Channel channel = future.channel();
            channel.writeAndFlush("Hello, Netty!");

            // 关闭连接
            channel.closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }
}