java7新增的一个小特性

最新推荐文章于 2025-12-26 18:13:00 发布

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原文链接：https://www.oreilly.com/content/java7-features/#:~:text=In%20Java%207%2C%20a%20new%20feature%20called%20invokedynamic,created%20to%20extend%20the%20support%20of%20dynamic%20languages.

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本文介绍Java7引入的新特性，即在数字字面量中使用下划线来提高可读性，例如可以将1000写为1_000。此外还介绍了在同一版本中引入的二进制字面量，如0b1，这使得开发者不再需要将其转换为十六进制。

Numeric literals with underscores
Numerical literals are definitely eye strainers. I am sure you would start counting the zeroes like me if you’ve been given a number with, say, ten zeros. It’s quite error prone and cumbersome to identify a literal if it’s a million or a billion unless you count the places from right to left. Not anymore. Java 7 introduced underscores in identifying the places. For example, you can declare 1000 as shown below:

int thousand = 1_000;
or 1000000 (one million) as follows

int million = 1_000_000
Note that binary literals are also introduced in this release too — for example “0b1” — so developers don’t have to convert them to hexadecimals any more.