java - 如何在Java中将String转换为int？(How do I convert a String to an int in Java?)

Question

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

(如何在Java中将String转换为int ？)

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

(我的字符串仅包含数字，我想返回它代表的数字。)

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

(例如，给定字符串"1234" ，结果应为数字1234 。)

  ask by Unknown user translate from so

Answer 1

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

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:

(如果您查看Java文档，您会发现“捕获”是此函数可以引发NumberFormatException ，当然您必须处理：)

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

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

(（此处理方式默认将格式错误的数字设置为0 ，但您可以根据需要执行其他操作。）)

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:

(另外，您可以使用Guava库中的Ints方法，该方法与Java 8的Optional结合使用，提供了一种强大而简洁的方法来将字符串转换为int：)

import com.google.common.primitives.Ints;

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