CompletableFuture.join()

`CompletableFuture.join()`是Java中用于异步编程的工具类`CompletableFuture`提供的一种方法，它主要用于阻塞当前线程，直到所有给定的完成阶段Future任务都已完成并且没有失败。当你有一个Future列表，并希望它们全部完成后继续执行后续操作，这时可以使用`join`。

例如：

CompletableFuture<String> future1 = ...;
CompletableFuture<String> future2 = ...;

List<CompletableFuture<String>> futures = Arrays.asList(future1, future2);
CompletableFuture<Void> combinedFuture = CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]));

combinedFuture.join(); // 线程会在这里等待，直到所有future完成

String result1 = future1.get();
String result2 = future2.get(); // 这里可以获取每个future的结果了

`join`方法如果任何一个Future抛出异常，`combinedFuture`也将立即失败并抛出异常。

相关问题

completableFuture.join

CompletableFuture.join() is a method in Java's CompletableFuture class that blocks the current thread until the CompletableFuture has completed its computation and returns the result of the computation. It is similar to calling get() method, but with one important difference: join() does not throw checked exceptions, so it can be used in lambda expressions and method references that do not declare any checked exceptions.

Here is an example of using join() method:

CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
    return "Hello";
});

String result = future.join();
System.out.println(result);

In this example, we create a CompletableFuture that returns the string "Hello" asynchronously using the supplyAsync() method. We then call the join() method on the CompletableFuture to block the current thread until the computation is completed and get the result of the computation. Finally, we print the result "Hello" to the console.

CompletableFuture.join

CompletableFuture.join()是一个阻塞方法，会等待Future的完成，返回Future的结果或者抛出Future的异常。具体而言，如果Future已经完成，那么join()立即返回结果；否则，join()会让当前线程阻塞，直到Future完成，然后返回结果或者抛出异常。它通常用于等待异步操作完成，然后获取其结果。