Using regular expressions in Java Pattern: java.util.regex.Pattern

[sony vijay]

Hi,

Say, I have a String like so: ts_20120413_dot_175531_dot_463_feed_user_at_gmail_dot_com_filename

This is a file name in the database which is prefixed with a timestamp, all dots and @ are replaced with _dot_ and _at_. I need to create a Pattern that matches Strings of the above type which can be split into three groups like so:

group1: ts_20120413_dot_175531_dot_463
group 2: user_at_gmail_dot_com
group 3: filename

I tried:

String input = ts_20120413_dot_175531_dot_463_feed_user_at_gmail_dot_com_filename;
final static Pattern FILEPATTERN = Pattern.compile("(ts_[1-9]+(_dot_[1-9]+)*)_feed_(.*)_([^_]*)");
Matcher m = FILEPATTERN.matcher(input);
if (!m.matches())
throw new Error("Invalid file name: " + input);
for (int i=1; i <= m.groupCount(); i++) {
String group = String.format("Group %s is: %s", i, m.group(i));
System.out.println(group);
}

The above code snippet throws the error: Invalid file name.
The expected output is:
Group 1 is: ts_20120413_dot_175531_dot_463
Group 2 is: user_at_gmail_dot_com
Group 3 is: filename

I can't figure out how to fix the error

- Sony

[Henry Wong]

 

sony vijay wrote:Hi,

Say, I have a String like so: ts_20120413_dot_175531_dot_463_feed_user_at_gmail_dot_com_filename

This is a file name in the database which is prefixed with a timestamp, all dots and @ are replaced with _dot_ and _at_. I need to create a Pattern that matches Strings of the above type which can be split into three groups like so:

group1: ts_20120413_dot_175531_dot_463
group 2: user_at_gmail_dot_com
group 3: filename

I tried:

String input = ts_20120413_dot_175531_dot_463_feed_user_at_gmail_dot_com_filename;
final static Pattern FILEPATTERN = Pattern.compile("(ts_[1-9]+(_dot_[1-9]+)*)_feed_(.*)_([^_]*)");
Matcher m = FILEPATTERN.matcher(input);
if (!m.matches())
throw new Error("Invalid file name: " + input);
for (int i=1; i <= m.groupCount(); i++) {
String group = String.format("Group %s is: %s", i, m.group(i));
System.out.println(group);
}

The above code snippet throws the error: Invalid file name.
The expected output is:
Group 1 is: ts_20120413_dot_175531_dot_463
Group 2 is: user_at_gmail_dot_com
Group 3 is: filename

I can't figure out how to fix the error

Hint: are there numbers that can't be matched with "[1-9]+" ??

Henry

[sony vijay]

I really want to break the first group before _feed starts. So, the following works

 Pattern.compile("(ts_.*)_feed_(.*)_([^_]*)");