Refer to column headings csv Groovy - csv

Question

I'm trying to figure out if there's a way of accessing column headings in a CSV using OpenCSV in groovy? This is what I have:
#GrabConfig( systemClassLoader=true )
#Grab( 'mysql:mysql-connector-java:5.1.27' )
#Grab(group = 'net.sf.opencsv', module = 'opencsv', version = '2.3')
import groovy.sql.Sql
import au.com.bytecode.opencsv.CSVReader
import au.com.bytecode.opencsv.CSVParser
def sql = Sql.newInstance("jdbc:mysql://localhost:3306/nid", "developer","whatever", "com.mysql.jdbc.Driver")
def notes = sql.dataSet("vdc_notifications")
def TEST_FILE_NAME = 'C:\\Users\\me\\Desktop\\test.csv'
List<String[]> rows = new CSVReader(new FileReader(new File(TEST_FILE_NAME)), CSVParser.DEFAULT_SEPARATOR, CSVParser.DEFAULT_ESCAPE_CHARACTER, CSVParser.DEFAULT_QUOTE_CHARACTER).readAll()
What i'm trying to get to is being able to do:
rows.each() { row -> println row.some_column_name }

Answer 1

usually the first row of a CSV file contains the names of the columns. so you can either use a simple parsing approach and take the first row for the header:
#Grab('net.sf.opencsv:opencsv:2.3')
import au.com.bytecode.opencsv.CSVReader
import au.com.bytecode.opencsv.bean.CsvToBean;
import au.com.bytecode.opencsv.bean.HeaderColumnNameMappingStrategy;
def csv = """\
name,age
Charlie,23
Billy,64"""
// read the files and keep the first one as the header
def csvr = new CSVReader(new StringReader(csv))
def header
while ((line=csvr.readNext())) {
if (!header) {
header = line
} else {
// create a map from the header and the line
println([header,line].transpose().collectEntries())
}
}
Or you can use the CsvToBean and the HeaderColumnNameMappingStrategy to create beans:
class Person {
String name
Integer age
}
// use the mapper
def ctb = new CsvToBean<Person>()
def hcnms = new HeaderColumnNameMappingStrategy<Person>()
hcnms.type = Person
println ctb.parse(hcnms, new StringReader(csv))