you can create custom nar file and then put into lib folder of $NIFI_HOME directory and restart your nifi server.   Add dependecy in processor module & then write a java code then build and create your nar file. <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi</artifactId> <version>4.1.2</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>4.1.2</version> </dependency> <dependency> <groupId>com.opencsv</groupId> <artifactId>opencsv</artifactId> <version>5.1</version> <exclusions> <exclusion> <artifactId>commons-logging</artifactId> <groupId>commons-logging</groupId> </exclusion> </exclusions> </dependency> /* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.anoop.converter; import com.opencsv.CSVReader; import com.opencsv.exceptions.CsvValidationException; import org.apache.nifi.annotation.behavior.*; import org.apache.nifi.components.PropertyDescriptor; import org.apache.nifi.flowfile.FlowFile; import org.apache.nifi.annotation.lifecycle.OnScheduled; import org.apache.nifi.annotation.documentation.CapabilityDescription; import org.apache.nifi.annotation.documentation.SeeAlso; import org.apache.nifi.annotation.documentation.Tags; import org.apache.nifi.processor.AbstractProcessor; import org.apache.nifi.processor.ProcessContext; import org.apache.nifi.processor.ProcessSession; import org.apache.nifi.processor.ProcessorInitializationContext; import org.apache.nifi.processor.Relationship; import org.apache.nifi.processor.io.StreamCallback; import org.apache.nifi.processor.util.StandardValidators; import org.apache.poi.ss.usermodel.Cell; import org.apache.poi.ss.usermodel.Row; import org.apache.poi.xssf.usermodel.XSSFSheet; import org.apache.poi.xssf.usermodel.XSSFWorkbook; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.util.ArrayList; import java.util.Collections; import java.util.HashSet; import java.util.List; import java.util.Set; @Tags({"csvToExcel"}) @CapabilityDescription("This processor can convert CSV flow files into Excel flow file") @SeeAlso({}) @ReadsAttributes({@ReadsAttribute(attribute="", description="")}) @WritesAttributes({@WritesAttribute(attribute="", description="")}) @InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED) public class CsvToExcel extends AbstractProcessor { public static final Relationship REL_SUCCESS = new Relationship.Builder() .name("original") .description("The original file") .build(); private List<PropertyDescriptor> descriptors; private Set<Relationship> relationships; @Override protected void init(final ProcessorInitializationContext context) { descriptors = Collections.emptyList(); relationships = new HashSet<>(); relationships.add(REL_SUCCESS); relationships = Collections.unmodifiableSet(relationships); } @Override public Set<Relationship> getRelationships() { return this.relationships; } @Override public final List<PropertyDescriptor> getSupportedPropertyDescriptors() { return descriptors; } @OnScheduled public void onScheduled(final ProcessContext context) {} @Override public void onTrigger(final ProcessContext context, final ProcessSession session) { FlowFile flowFile = session.get(); if ( flowFile == null ) { return; } session.write(flowFile, new Converter()); session.putAttribute(flowFile,"convertedIntoExcel","true"); session.transfer(flowFile,REL_SUCCESS); } } class Converter implements StreamCallback { @Override public void process(InputStream in, OutputStream out) throws IOException { try { streamConversion(in,out); } catch (CsvValidationException e) { throw new RuntimeException(e); } } private void streamConversion(InputStream in, OutputStream out) throws IOException, CsvValidationException { CSVReader csvReader = new CSVReader(new InputStreamReader(in)); XSSFWorkbook workbook = new XSSFWorkbook(); XSSFSheet sheet = workbook.createSheet("Sheet1"); String[] rowData = null; int rowNum = 0; while ((rowData = csvReader.readNext()) != null) { Row row = sheet.createRow(rowNum++); int colNum = 0; for (String cellData : rowData) { Cell cell = row.createCell(colNum++); cell.setCellValue(cellData); } } workbook.write(out); workbook.close(); } }   ... View more