将Optional的值分配给变量(如果存在) [英] Assign value of Optional to a variable if present

问题描述

我正在使用Java Optional.我看到Optional有一个ifPresent方法.

Hi I am using Java Optional. I saw that the Optional has a method ifPresent.

代替做类似的事情:

Optional<MyObject> object = someMethod();
if(object.isPresent()) {
    String myObjectValue = object.get().getValue();
}

我想知道如何使用Optional.ifPresent()将值分配给变量.

I wanted to know how I can use the Optional.ifPresent() to assign the value to a variable.

我正在尝试类似的事情:

I was trying something like:

String myValue = object.ifPresent(getValue());

要获取分配给该变量的值，我需要lambda函数是什么?

What do I need the lambda function to be to get the value assigned to that variable?

推荐答案

您可以使用 #orElse 或 orElseThrow 来提高代码的可读性.

You could use #orElse or orElseThrow to improve the readbility of your code.

Optional<MyObject> object = someMethod();
String myValue = object.orElse(new MyObject()).getValue();

---

Optional<MyObject> object = someMethod();
String myValue = object.orElseThrow(RuntimeException::new).getValue();

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