Objects.requireNonNull（T obj）而不是null检查并手动抛出IllegalArgumentException？ [英] Objects.requireNonNull(T obj) instead of null checks and manually thrown IllegalArgumentException?

问题描述

每当我必须检查方法的给定参数是否为空时，我曾经写过一个空检查并抛出 IllegalArgumentException 如果空检查失败：

Whenever I had to check if the given parameters to a method are not null, I used to write a null check and throw a IllegalArgumentException if the null check fails:

    if (user == null) {
        throw new IllegalArgumentException("User can't be null.");
    }

但是，通过阅读某些Java 8类的源代码，例如 ArrayList ，我发现Oracle正在使用 Objects.requireNonNull 检查参数是否为空值，然后，如果测试失败，则< a href =https://docs.oracle.com/javase/8/docs/api/java/lang/NullPointerException.html =nofollow noreferrer> NullPointerException 。

However, by reading the source code of some Java 8 classes such as ArrayList, I found out that Oracle are using Objects.requireNonNull to check a parameter against a null value, and then, if the test fails, a NullPointerException is thrown.

这样，早期的代码片段应该采用这种方法：

This way, the earlier code snippet should look like this by adopting this approach:

Objects.requireNonNull(user, "User can't be null.");

更小，更易读。

假设我控制了系统的整个异常处理，（即使我不应该，有时它是处理这些未经检查的异常的业务的一部分），我应该替换我的 IllegalArgumentException 使用 NullPointerException 并使用 Objects.requireNonNull 而不是编写我自己的null检查和异常抛出？

Assuming that I have control of the whole exception handling of the system, (even that I shouldn't, sometimes it is part of the business to handle these unchecked exceptions), should I replace my IllegalArgumentException with NullPointerException and use Objects.requireNonNull instead of writing my own null checking and exception throwing?

推荐答案

使用 Objects.requireNonNull（c）是一种非常优雅的方法来检查元素是否为空。但是有一个有趣的讨论是关于选择 NullPointerException 还是 IllegalArgumentException - > 有空参数的IllegalArgumentException或NullPointerException？。因此抛出 NullPointerException 是表达引用为空的java方式。

Using Objects.requireNonNull(c) is a very elegant way to check if the element is not null. But there is an interesting discussion about whether choosing NullPointerException or IllegalArgumentException --> IllegalArgumentException or NullPointerException for a null parameter?. So throwing NullPointerException is the java way to express that a reference is null.

否则，您可以创建自己的方法 requireNotNull（）。这很简单：

Otherwise, you can make your own method requireNotNull(). It is simple :

 public static <T> T requireNonNull(T obj) {
        if (obj == null)
            throw new NullPointerException();
        return obj;
    }

您可以更改异常 NullPointerException by IllegalArgumentException 。

and you can change the exception NullPointerException by IllegalArgumentException.

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