CompletableFuture.complete 和 CompletableFuture.get的使用方法

CompletableFuture.complete方法用于手动完成一个CompletableFuture，可以将结果值或异常传递给它。例如，可以使用以下代码手动完成一个CompletableFuture：

CompletableFuture<String> future = new CompletableFuture<>();
future.complete("Hello World");

CompletableFuture.get方法用于等待CompletableFuture的完成并返回结果值。如果CompletableFuture还没有完成，get方法将阻塞当前线程直到CompletableFuture完成。例如，可以使用以下代码等待CompletableFuture的完成并获取结果值：

CompletableFuture<String> future = CompletableFuture.completedFuture("Hello World");
String result = future.get();

需要注意的是，如果CompletableFuture完成时抛出了异常，get方法将抛出ExecutionException异常，并将原始异常作为其原因。可以使用try-catch块来处理这种情况。

相关问题

CompletableFuture.get

CompletableFuture.get() is a method used to retrieve the result of a CompletableFuture. It blocks the current thread until the CompletableFuture completes and returns the result of the computation or throws an exception if the computation failed.

The get() method has two overloaded versions: one without any arguments and another with a timeout parameter. The first version blocks indefinitely until the CompletableFuture completes, whereas the second version blocks for the specified timeout duration and throws a TimeoutException if the CompletableFuture does not complete within that time.

It is important to note that calling the get() method on a CompletableFuture may cause the calling thread to block, which can impact performance and scalability in certain situations. As such, it is recommended to use asynchronous methods like thenApply(), thenCompose(), or handle() instead of get() whenever possible.

CompletableFuture.supplyAsync(）什么用法

The `CompletableFuture.supplyAsync()` method is used to create and execute an asynchronous task that returns a result. It takes a `Supplier` functional interface as a parameter, which provides the result of the computation. The method returns a `CompletableFuture` object that represents the result of the computation.

Here is an example code snippet that demonstrates the usage of `CompletableFuture.supplyAsync()` method:

CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
    // Perform some expensive computation here
    return "Result of the computation";
});

// Do some other work while the computation is running in the background

String result = future.get(); // This will block until the computation is complete and return the result

In this example, we create a `CompletableFuture` that will execute the computation asynchronously using the default executor. The `get()` method is called on the future to block and wait for the result of the computation. This allows us to perform other work while the computation is running in the background. Once the computation is complete, the result can be obtained from the future.