Parsing a text file in Java

Kingp35

I need a bit of help parsing a text file in Java as its been a while since I have done it. I have a text file that contains lines of input like the following.

write[12,43]
write[15,43]
read[12,67]
commit[12]
abort[15]

I need to set 3 variables. One as the operation name part (write, commit etc), one for the first number and one for the second (when required).

Could someone please point me in the right direction as to how to do this? I know it could be done much easier using PERL but it must be done in JAVA.

Thanks

Kingp35

Can you use regular expressions in java like in perl and if so, how?

timeout

well I take it you know how to read in the values from a text file so all that is need is your regular expression. This tutorial should help http://java.sun.com/docs/books/tutorial/extra/regex/

Timeout

Kingp35

Yes I know how to read in lines of a text file its the breaking up into its pieces that im having problems with. That tutorial looks helpfull. Ill have a look through it.

NutJob

would Xml be usefull here (have code i can throw you)

if not u could seperate using a tab or comma and use String liburary (indexof() .....)
to parse it out (old school)


By breaking it up what do u mean. Using the string liburary to parse it up as regular expressions can do that neatly.
Or
Converting integers and stuff back to ints

Mutant_Fruit

if the text is that simple, try using a string.indexof("[") type thing to find the read/write/commit/abort section. Then see if the remainder contains a "," symbol. If it does, you split it by the "," and parse the two integers out. Otherwise you know you only have 1 number, and you can just parse that out.

Theres no need to use regex or xml.

Hobbes

Its pretty easy if you can read the file already.

Something like.

StringTokenizer st= new StringTokenizer(s,"[,]");

Then read the first token which will always be a command. After that use that token to determine how to read the remainder but you can still use the stringtokenizer to pull the items from it.

Something like.

String command = st.nextToken();

if (command.equalsIgnoreCase("write") {
    String arg1 = st.nextToken();
    String arg2 = st.nextToken();
}
else if (command.equalsIgnoreCase("commit") { 
    String arg1 = st.nextToken();
}

Of course this assumes you are getting in fixed formatting arguments.

Kingp35

Thanks guys, got it working.