关于JAVA中split()函数遇到的一点问题

很简单的，就是想分割一个文件路径字符串，取它的扩展名。

String file=new String("c:\\test\\file.exe");

String[] temp = file.split(".");

程序运行到这里，就异常终止了。想想以前用split分割很多种符号，都没问题。随手试了试split("\\")，依然失败。又换了其他的各种符号":"、"##"等等却又没问题。难道"."和"\\"有什么不对么？

在仔细看看JDK的文档：

String[] java.lang.String.split(String regex)

split

public String[] split(String regex)

Splits this string around matches of the given regular expression.

This method works as if by invoking the two-argument split method with the given expression and a limit argument of zero. Trailing empty strings are therefore not included in the resulting array.

The string "boo:and:foo", for example, yields the following results with these expressions:

Regex Result

: { "boo", "and", "foo" }

o { "b", "", ":and:f" }

Parameters:

regex - the delimiting regular expression

Returns:

the array of strings computed by splitting this string around matches of the given regular expression

Throws:

PatternSyntaxException - if the regular expression's syntax is invalid

Since:

1.4

See Also:

Pattern

清清楚楚的写着参数是String regex，一个regular expression，正则表达式。哎，以前没认真看过，一直当成普通的字符串在用了，只是运气好，恰好没出错。知错就改：

改成String[] temp = file.split("\\.");或者String[] temp = file.split("[.]");就可以了。至于那个"\\"分割的话，用String[] temp = file.split("\\\\");就可以了。