Vertx 文檔建議executeBlocking()在需要調用阻塞 API 時使用方法。另一方面，Vertx 還提供了一個 Future 的概念，它基本上做同樣的事情。但該executeBlocking()方法不是靜態的。它也不是 Future 的簡單包裝器，如果您查看它的實現，您會發現它非常復雜。這兩者有什么區別？假設我想以異步方式執行一些長時間運行的任務。這兩種方法有什么區別嗎？方法一：doTheJob() { Future<Void> future = Future.future(); executeLongRunningBlockingOperation(); future.complete(); return future;}doTheJob().setHandler(asyncResult -> { // ... handle result});方法二：vertx.executeBlocking(future -> { executeLongRunningBlockingOperation(); future.complete();}, res -> { // ... handle result});
1 回答
慕后森
TA貢獻1802條經驗 獲得超5個贊
您的第一個示例不是Future. 調用executeLongRunningBlockingOperation()將阻塞主線程，直到該方法完成——也就是說，在阻塞操作完成之前不會發生任何其他事情。在您的第二個示例中，阻塞調用被分拆到后臺線程中，并且其他事情在它執行時繼續發生。
為了用更完整的示例說明這一點，此代碼：
public void executeLongRunningBlockingOperation() {
Thread.sleep(5000);
}
public Future<Void> doTheJob() {
System.out.println("Doing the job...");
Future<Void> future = Future.future();
executeLongRunningBlockingOperation();
// this line will not be called until executeLongRunningBlockingOperation returns!
future.complete();
// nor will this method! This means that the method won't return until the long operation is done!
return future;
}
public static void main(String[] args) {
doTheJob().setHandler(asyncResult -> {
System.out.println("Finished the job");
});
System.out.println("Doing other stuff in the mean time...");
}
將產生以下輸出：
Doing the job...
Finished the job
Doing other stuff in the mean time...
而這段代碼（使用executeBlocking）：
...
public Future<Void> doTheJob() {
System.out.println("Doing the job...");
Future<Void> future = Future.future();
Vertx vertx = Vertx.vertx();
vertx.executeBlocking(call -> {
executeLongRunningBlockingOperation();
call.complete;
}, result -> {
// this will only be called once the blocking operation is done
future.complete();
});
// this method returns immediately since we are not blocking the main thread
return future;
}
...
將產生：
Doing the job...
Doing other stuff in the mean time...
Finished the job
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