用Java解析文本文件

Question

I have a text file that contains one line. Something like this: A10102012MikeM. The first letter can be either A or P, following numbers correspond to date, next comes name, and then gender(M or F). What is the best method to parse this info into Map ? Of course i can take string.substring(x,y) of each element. But it seems too hard-coded. Can this be accomplished with regex somehow??

Answer 1

Try this regex ^(A|P)(\\d+)(\\w+?)(M|F)$ .This will work but some conditions:

1) It will not check date validity.

2) Output should be exactly as you described otherwise it may fail.

String str = "A10102012MikeM";

String p = "^([A|P])(\\d+)(\\w+?)(M|F)$";
Pattern pattern = Pattern.compile(p);
Matcher matcher = pattern.matcher(str);
if (matcher.find()){
System.out.println(matcher.group(1));
System.out.println(matcher.group(2));
System.out.println(matcher.group(3));
System.out.println(matcher.group(4));
}

output =

A 10102012 Mike M

Answer 2

Yes, Java has very good support for regexes. You will want to check out java.util.regex.Pattern . Pay special attention to the Matcher groups which will let you extract data from the regex matches.

Answer 3

^(A|P)([0-9]){10}(.+)(M|F)$

• Group 1 ... A or P
• Group 2 ... 10 digit date
• Group 3 ... The name
• Group 4 ... M or F (gender)

Answer 4

^([AP])(\d+)([A-Za-z]+?)([MF])$

这个正则表达式（转义未完成）将不同部分的数据捕获到组中，以便您可以更轻松地获取它们。

Answer 5

A possible alternative to regex, depending on your exact situation, may be the flatworm project on sourceforge. For example, it can read the text file and populate java objects for you.

They've got a good field guide that walks through a number of use cases.