Manuvidya change request , not worked with * split alternative is

reading csv file as array ; checking specific row and verifying coloums and modifying data and 

resending back, 

no xml convertion; read as array as lines; checking require index and change its content. 

see the output file

import com.sap.gateway.ip.core.customdev.util.Message

import groovy.util.XmlParser

import java.util.HashMap;

import java.util.*;

def Message processData(Message message) {

   

        def body = message.getBody(java.lang.String) as String

        body=body.replaceAll("\\*","#")

        

    def lines = body.split('\n')

// Split the second line by '*' delimiter (escape the asterisk *)

def fields = lines[1].split("#")

// Modify the 5th field (index 4) to substring the first 4 characters

fields[5] = fields[5][0..3]

// Reconstruct the second line with modified field

lines[1] = fields.join('#')

// Join the lines back to form the output string

 def outputString = lines.join('\n')

 message.setBody(outputString.replaceAll("#","\\*"))

//message=message1;

    return message

}

input

ISA*00*          *00*          *01*002331536      *ZZ*PHOENIXUS2     *230911*1628*U*00401*1104     *0*P*^~

GS*IN*002331536*PHOENIXUS2*20230911*162848*1104*X*004010~

ST*810*1104~

BIG*20230904*6100001992**ANSI testing PHNINT~

REF*PK*6100001992~

DTM*011*20230904~

IT1*5*3*EA*600**BP****PL*5~

TDS*187200~

TXI*ST*72.00~

CTT*1*3~

SE*9*1104~

GE*1*1104~

IEA*1*1104~

output

ISA*00*          *00*          *01*002331536      *ZZ*PHOENIXUS2     *230911*1628*U*00401*1104     *0*P*^~

GS*IN*002331536*PHOENIXUS2*20230911*1628*1104*X*004010~

ST*810*1104~

BIG*20230904*6100001992**ANSI testing PHNINT~

REF*PK*6100001992~

DTM*011*20230904~

IT1*5*3*EA*600**BP****PL*5~

TDS*187200~

TXI*ST*72.00~

CTT*1*3~

SE*9*1104~

GE*1*1104~

IEA*1*1104~