string的split问题，没分了求救！

[dongfeng0803]

请教我用如下代码来分割文本时

		while(in.hasNextLine()){
			String text = in.next();
			String[] field = text.split(",");
			System.out.println(field.length);
		}

文本如下（每行都是用5个“,”分开的字段，可以为空）：

201109290140,507842208552,,,,
201109290104,507842330578,腾讯,,休闲娱乐\游戏\家园,
201109290227,490012727652,手机阅读,手机阅读,休闲娱乐\小说\手机阅读,

为什么第一个的field.length为2，第二、三个为5呢？我要提取第4个的字段该怎么做？

[程序源自程序猿]

因为分割后，java中会从后面开始检查所得的数组，把空的去掉，返回非空的

[newbie_Lee]

查阅API:

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" }

[coooliang]

没用过guava，学习了！

[JAKCXPP]

2楼正解

[swoky]

换个其它的方水法吧:
比如guava

		String s = "201109290140,507842208552,,,,";
		Iterator<String> it = Splitter.on(",").split(s).iterator();
		while (it.hasNext()) {
			System.out.println("hah:" + it.next());
		}

[朱超ZhuChao.Tech]

[Quote=引用 4 楼 的回复:]
换个其它的方水法吧:
比如guava


Java code


String s = "201109290140,507842208552,,,,";
Iterator<String> it = Splitter.on(",").split(s).iterator();
while (it.hasNext()) {
……
[/Quote]

+1

[地雷]

用commons下面的StringUtils里面的字符串分割方法可以实现保留空值。
比如splitByWholeSeparatorPreserveAllTokens

StringUtils.splitByWholeSeparatorPreserveAllTokens("ab   de fg", null)    = ["ab", "", "", "de", "fg"]

可以参考下面的api
http://commons.apache.org/lang/api-2.5/org/apache/commons/lang/StringUtils.html#split(java.lang.String)