Java Sonar NullPointerException

Question

我有错误

A "NullPointerException" could be thrown; "btn" is nullable here.

代码:

Button btn = getButton();
Assert.assertNotNull ("No button", btn);
btn.click();

除以下情况外，我如何解决此问题:

Button btn = getButton();
if (btn != null) {
  btn.click();
}

Answer 1

如果您使用的是java-8，那么您可以使用Optional

Optional<Button> btn = getButton();//need to let return to Optional<Button>
btn.ifPresent(b -> b.click());