how to insert Multiple records in REST request?

Below is my sample REST request:

{

"nav_artprc" : [
{
"Article" : "11111",
"Site" : "32",
"Partner" : "12345566"
},

{
"Article" : "12111",
"Site" : "12",
"Partner" : "12345566"
}
]
}

I am able to fetch it from my groovy script now using the below codes:

def slurper = new groovy.json.JsonSlurper()

import groovy.json.JsonOutput

def s = testRunner.testCase.getPropertyValue( "article")
def list = s.split(',')
def i = Integer.parseInt(testRunner.testCase.getPropertyValue("counter"))
def output = " "
//log.info list.size()
for (i=0; i < list.size(); i++) {
//log.info list[i]
def output1 = new String[3]
output1[i] = JsonOutput.toJson([Article: list[i],Site: '32',Partner: '1234566']).concat(',')
// log.info output1[i]
output = output.concat(output1[i])
log.info output
// i++

testRunner.testCase.setPropertyValue( "counter", i.toString())

}
def propRemove = output[0..-2]
log.info propRemove
def first = '{"nav_artprc" : [ '
def second = ' ]}'
def prop1 = first.concat(propRemove)
def prop = prop1.concat(second)

log.info prop
testRunner.testCase.testSteps["Properties"].setPropertyValue( "Pro", prop )
testRunner.testCase.setPropertyValue( "counter", new Integer(0).toString())

But I am unable to fetch multiple records from EXCEL sheet.

How I should fetch that?

Please suggest