将 Integer（可能为 null）转换为 Java 中的 int 的更好方法？

Question

An Integer can be null . I convert an Integer to an int by:

Integer integer = null;
int i;

try {
    i = integer.intValue();
}
catch (NullPointerException e) {
    i = -1;
} 

Is there a better way?

Answer 1

避免异常总是更好。

int i = integer != null ? integer.intValue() : -1;

Answer 2

If you already have guava in your classpath, then I like the answer provided by michaelgulak .

Integer integer = null;
int i = MoreObjects.firstNonNull(integer, -1);

Answer 3

Java 9 introduce Objects.requireNonNullElse , alternative solution in Java Vanilla (without external library):

Integer integerValue = null;
int intValue = Objects.requireNonNullElse(integerValue, 0);

Answer 4

使用Java8，以下工作也是如此：

Optional.ofNullable(integer).orElse(-1)

Answer 5

Apache Commons Lang 3

ObjectUtils.firstNonNull(T...)

Java 8 Stream

Stream.of(T...).filter(Objects::nonNull).findFirst().orElse(null)

Taken From: https://stackoverflow.com/a/18741740/6620565