open text file, modify text, place into sql database with groovy - database

Question

I have a text file that has a large grouping of numbers (137mb text file) and am looking to use groovy to open the text file, read it line-by-line, modify the numbers, and then place them into a database (as strings). There are going to be 2 items per line that need to be written to separate database columns, which are related.
My text file looks as such:
A.12345
A.14553
A.26343
B.23524
C.43633
C.23525
So the flow would be:
Step 1.The file is opened
Step 2.Line 1 is red
Step 3.Line 1 is split into letter/number pair [:]
Step 4.The number is divided by 10
Step 5.Letter is written to letter data base (as string)
Step 6.Number is written to number database (as string)
Step 7.Letter:number pair is also written to a separate comma separated text file.
Step 8.Proceed to next line (line 2)
Output text file should look like this:
A,1234.5
A,1455.3
A,2634.3
B,2352.4
C,4363.3
C,2352.5
Database for numbers should look like this:
1:1234.5
2:1455.3
3:2634.3
4:2352.4
5:4363.3
6:2352.5
*lead numbers are database index locations, for relational purpose
Database for letters should look like this:
1:A
2:A
3:A
4:B
5:C
6:C
*lead numbers are database index locations, for relational purpose
I have been able to do most of this; the issue I am running into is not be able to use the .eachLine( line -> ) function correctly... and have NO clue how to output the values to the databases.
There is one more thing I am quite dense about, and that is the instance where the script encounters an error. The text file has TONS of entries (around 9000000) so I am wondering if there is a way to make it so if the script fails or anything happens that I can restart the script from the last modified line.
Meaning, the script has an error (my computer gets shut down somehow) and stops running at line 125122 (completes modification of line 125122) of the text file... how do I make it so when I start the script the second time run the script at line 125123.
Here is my sample code so far:
//openfile
myFile = new File("C:\\file.txt")
//set fileline to target
printFileLine = { it }
//set target to argument
numArg = myFile.eachLine( printFileLine )
//set argument to array split at "."
numArray = numArg.split(".")
//set int array for numbers after the first char, which is a letter
def intArray = numArray[2] { it as int } as int
//set string array for numbers after the first char, which is a letter
def letArray = numArray[1] { it as string }
//No clue how to write to a database or file... or do the persistence thing.
Any help would be appreciated.

Answer 1

I would use a loop to cycle over every line within the text file, I would also use Java methods for manipulating strings.
def file = new File('C:\\file.txt')
StringBuilder sb = new StringBuilder();
file.eachLine { line ->
//set StringBuilder to new line
sb.setLength(0);
sb.append(line);
//format string
sb.setCharAt(1, ',');
sb.insert(5, '.');
}
You could then write each line to a new text file, example here. You could use a simple counter (e.g. counter = 0; and then counter++;) to store the latest line that has been read/written and use that if an error occurs. You could catch possible errors within a try/catch statement if you are regularly getting crashes also.
This guide should give you a good start with working with a database (presuming SQL).
Warning, all of this code is untested and should hopefully give you more direction. There are probably many other ways to solve this differently, so keep an open mind.