如何在 Java 中将 String 转换为 int? [英] How do I convert a String to an int in Java?

问题描述

如何在 Java 中将 String 转换为 int?

How can I convert a String to an int in Java?

我的字符串只包含数字，我想返回它代表的数字.

My String contains only numbers, and I want to return the number it represents.

例如，给定字符串"1234"，结果应该是数字1234.

For example, given the string "1234" the result should be the number 1234.

推荐答案

String myString = "1234";
int foo = Integer.parseInt(myString);

如果您查看 Java 文档 你会注意到catch"就是这个函数会抛出NumberFormatException，当然你要处理:

If you look at the Java documentation you'll notice the "catch" is that this function can throw a NumberFormatException, which of course you have to handle:

int foo;
try {
   foo = Integer.parseInt(myString);
}
catch (NumberFormatException e)
{
   foo = 0;
}

(这种处理默认格式错误的数字为 0，但如果您愿意，您可以做其他事情.)

(This treatment defaults a malformed number to 0, but you can do something else if you like.)

或者，您可以使用 Guava 库中的 Ints 方法，该方法与 Java 8 的 Optional 相结合，提供了一种强大而简洁的方法将字符串转换为一个整数:

Alternatively, you can use an Ints method from the Guava library, which in combination with Java 8's Optional, makes for a powerful and concise way to convert a string into an int:

import com.google.common.primitives.Ints;

int foo = Optional.ofNullable(myString)
 .map(Ints::tryParse)
 .orElse(0)

这篇关于如何在 Java 中将 String 转换为 int?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！