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01-20-2023
09:38 PM
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();
}
}
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