为什么有BigInteger(String)但没有BigInteger(long)? [英] Why is there BigInteger(String) but no BigInteger(long)?

问题描述

在Java中，要使用构造函数new BigInteger(String)将String转换为BigInteger，而要使用工厂函数BigInteger.valueof(long)转换int/long，为什么?

In Java, to convert a String to BigInteger you use the constructor new BigInteger(String) but to convert an int/long you use the factory function BigInteger.valueof(long), why is that?

推荐答案

实际上是一个BigInteger(long)构造函数，但它是私有的.工厂方法上的javadoc提供有关原因的信息:

There actually is a BigInteger(long) constructor, but it's private. The javadoc on the factory method provides info on why:

此静态工厂方法"优先于(长)提供 构造函数，因为它允许重复使用经常使用的 BigIntegers.

This "static factory method" is provided in preference to a (long) constructor because it allows for reuse of frequently used BigIntegers.

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