JDK future 与 netty future promise 实例
所属分类 netty
浏览量 84
java.util.concurrent.Future
io.netty.util.concurrent.Future
io.netty.util.concurrent.Promise
io.netty.util.concurrent.Future extends java.util.concurrent.Future
io.netty.util.concurrent.Promise extends io.netty.util.concurrent.Future
jdk自带的Future只能同步等待结果。
netty自带的Future能同步等待结果,也可以用异步的方式(如:使用addListener方法设置回调方法)等待结果。
Promise有Future的所有功能,脱离任务独立存在(可以主动创建并赋结果),可作为线程之间传递结果的容器。
import io.netty.channel.EventLoop;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.util.concurrent.DefaultPromise;
import io.netty.util.concurrent.GenericFutureListener;
import io.netty.util.concurrent.Promise;
import java.time.LocalDateTime;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
public class FutureAndPromiseDemo {
public static void main(String[] args) throws Exception{
ExecutorService executor = Executors.newFixedThreadPool(2);
Future future = executor.submit(new Callable() {
@Override
public String call() throws Exception {
Thread.sleep(1000);
return "result,"+ LocalDateTime.now();
}
});
System.out.println(future.get());
// netty future
NioEventLoopGroup eventExecutors = new NioEventLoopGroup();
EventLoop eventLoop = eventExecutors.next();
io.netty.util.concurrent.Future nettyfuture = eventLoop.submit(new Callable() {
@Override
public String call() throws Exception {
Thread.sleep(1000);
return "netty_future_result_"+LocalDateTime.now();
}
});
nettyfuture.addListener(new GenericFutureListener>() {
@Override
public void operationComplete(io.netty.util.concurrent.Future super String> future) throws Exception {
// get or getNow
System.out.println(future.getNow());
}
});
System.out.println(LocalDateTime.now());
Thread.sleep(2000);
// promise
Promise promise = new DefaultPromise<>(eventLoop);
new Thread(()->{
try {
Thread.sleep(1000);
promise.setSuccess("netty_promise_result_"+LocalDateTime.now());
} catch (Exception e) {
promise.setFailure(e);
}
}).start();
System.out.println(LocalDateTime.now());
System.out.println(promise.get());
}
}
https://gitee.com/dyyx/netty-learning-example/blob/master/netty-iot/src/main/java/com/sanshengshui/iot/test/FutureAndPromiseDemo.java
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