Java 如何将String转换为Int

Java 必知必会 第 6 篇

如何将String转换为Int

有两种方式

Integer x = Integer.valueOf(str); // or int y = Integer.parseInt(str);

这两种方式有一点点不同：

valueOf返回的是java.lang.Integer的实例parseInt返回的是基本数据类型 int

Short.valueOf/parseShort,Long.valueOf/parseLong等也是有类似差别。

另外还需注意的是，在做int类型转换时，可能会抛出NumberFormatException，因此要做好异常捕获

int foo; String StringThatCouldBeANumberOrNot = "26263Hello"; //will throw exception String StringThatCouldBeANumberOrNot2 = "26263"; //will not throw exception try { foo = Integer.parseInt(StringThatCouldBeANumberOrNot); } catch (NumberFormatException e) { //Will Throw exception! //do something! anything to handle the exception. } try { foo = Integer.parseInt(StringThatCouldBeANumberOrNot2); } catch (NumberFormatException e) { //No problem this time but still it is good practice to care about exceptions. //Never trust user input :) //do something! anything to handle the exception. }