关于Java的String.split方法的具体使用方法

Java String的split方法的在处理不同的limit的时候，会有非常不同的结果，而且关键还有trailing empty strings，这可能会影响到最后得到的String数组的length。

摘自Java doc 6：http://docs.oracle.com/javase/6/docs/api/java/lang/String.html#split%28java.lang.String,%20int%29

split

public String[] split(String regex,int limit)

Splits this string around matches of the given regular expression.

The array returned by this method contains each substring of this string that is terminated by another substring that matches the given expression or is terminated by the end of the string. The substrings in the array are in the order in which they occur in this string. If the expression does not match any part of the input then the resulting array has just one element, namely this string.

The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array. If the limitn is greater than zero then the pattern will be applied at most n - 1 times, the array's length will be no greater thann, and the array's last entry will contain all input beyond the last matched delimiter. Ifn is non-positive then the pattern will be applied as many times as possible and the array can have any length. Ifn is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.

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

Regex	Limit	Result
:	2	{ "boo", "and:foo" }
:	5	{ "boo", "and", "foo" }
:	-2	{ "boo", "and", "foo" }
o	5	{ "b", "", ":and:f", "", "" }
o	-2	{ "b", "", ":and:f", "", "" }
o	0	{ "b", "", ":and:f" }

An invocation of this method of the form str.split(regex, n) yields the same result as the expression

Pattern.compile(regex).split(str, n)