fixed-length-record

Is there any framework/library to help writing fixed length flat files in java? I want to write a collection of beans/entities into a flat file without worrying with convertions, padding, alignment, fillers, etcs For example, I'd like to parse a bean like: public class Entity{ String name = "name"; // length = 10; align left; fill with spaces Integer id = 123; // length = 5; align left; fill with spaces Integer serial = 321 // length = 5; align to right; fill with '0' Date register = new Date();// length = 8; convert to yyyyMMdd } ... into ... name 123 0032120110505 mikhas 5000 0122120110504

I need to match a fixed width field on a file layout with a regular expression. The field is numeric/integer, always have four characters and is included in the range of 0..1331. When the number is smaller than 1000, the string is filled with left zeros. So all these examples are valid: 0000 0001 0010 1000 1331 But the following must be not accepted: 1 01 10 100 4759 It would be nice if I could enforce this restriction only with regex. After playing a bit, I yielded the expression \0*[0-1331]\ . The problem is that it does not restrict the size to four characters. Of course I could do \000[0-9

What's the best way to read a fixed length record in Perl. I know to read a file like: ABCDE 302 DEFGC 876 I can do while (<FILE>) { $key = substr($_, 0, 5); $value = substr($_, 7, 3); } but isn't there a way to do this with read/unpack? runrig Update: For the definitive answer, see Jonathan Leffler's answer below. I wouldn't use this for just two fields (I'd use pack / unpack directly), but for 20 or 50 or so fields I like to use Parse::FixedLength (but I'm biased). E.g. (for your example) (Update: also, you can use $/ and <> as an alternative to read($fh, $buf, $buf_length)...see below): use

I am trying to find a better solution to convert a plain text (but with predefined lengths for each field) to xml. For example the input text can be "Testuser new york 10018", the first 11 characters indicates user name, next 12 character indicates city and next 5 characters indicates zip code. So I need to form a xml from the above string with predefined field lengths. I am thinking 2 approaches Define a business entity and fill the entity properties by using substring functions on the input text and then serialize the entity to xml Predefine the xml structure, use xslt to navigate to each