Apache
/
nifi
mirror of https://github.com/apache/nifi.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

NIFI-4112: Fix ConvertExcelToCSV to handle empty cells. 

Signed-off-by: Matt Burgess <mattyb149@apache.org>

This closes #1973
This commit is contained in:
Koji Kawamura 2017-07-04 16:30:19 +09:00 committed by Matt Burgess
parent 8acee02393
commit 5c48655e69
6 changed files with 227 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
nifi-nar-bundles/nifi-poi-bundle/nifi-poi-processors/pom.xml
View File

@ -29,6 +29,19 @@
<artifactId>nifi-poi-processors</artifactId>
<packaging>jar</packaging>
<build>
<plugins>
<plugin>
<groupId>org.apache.rat</groupId>
<artifactId>apache-rat-plugin</artifactId>
<configuration>
<excludes combine.children="append">
<exclude>src/test/resources/with-blank-cells.csv</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<!-- https://mvnrepository.com/artifact/xerces/xerces -->
<dependency>

79
nifi-nar-bundles/nifi-poi-bundle/nifi-poi-processors/src/main/java/org/apache/nifi/processors/poi/ConvertExcelToCSVProcessor.java
View File

@ -24,6 +24,8 @@ import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.io.FilenameUtils;
import org.apache.commons.lang3.StringUtils;
@ -78,6 +80,7 @@ public class ConvertExcelToCSVProcessor
public static final String SOURCE_FILE_NAME = "sourcefilename";
private static final String SAX_CELL_REF = "c";
private static final String SAX_CELL_TYPE = "t";
private static final String SAX_CELL_ADDRESS = "r";
private static final String SAX_CELL_STRING = "s";
private static final String SAX_CELL_CONTENT_REF = "v";
private static final String SAX_ROW_REF = "row";
@ -85,6 +88,7 @@ public class ConvertExcelToCSVProcessor
private static final String DESIRED_SHEETS_DELIMITER = ",";
private static final String UNKNOWN_SHEET_NAME = "UNKNOWN";
private static final String SAX_PARSER = "org.apache.xerces.parsers.SAXParser";
private static final Pattern CELL_ADDRESS_REGEX = Pattern.compile("^([a-zA-Z]+)([\\d]+)$");
public static final PropertyDescriptor DESIRED_SHEETS = new PropertyDescriptor
.Builder().name("extract-sheets")
@ -279,6 +283,27 @@ public class ConvertExcelToCSVProcessor
}
}
static Integer columnToIndex(String col) {
int length = col.length();
int accumulator = 0;
for (int i = length; i > 0; i--) {
char c = col.charAt(i - 1);
int x = ((int) c) - 64;
accumulator += x * Math.pow(26, length - i);
}
// Make it to start with 0.
return accumulator - 1;
}
private static class CellAddress {
final int row;
final int col;
private CellAddress(int row, int col) {
this.row = row;
this.col = col;
}
}
/**
* Extracts every row from an Excel Sheet and generates a corresponding JSONObject whose key is the Excel CellAddress and value
@ -290,6 +315,10 @@ public class ConvertExcelToCSVProcessor
private SharedStringsTable sst;
private String currentContent;
private boolean nextIsString;
private CellAddress firstCellAddress;
private CellAddress firstRowLastCellAddress;
private CellAddress previousCellAddress;
private CellAddress nextCellAddress;
private OutputStream outputStream;
private boolean firstColInRow;
long rowCount;
@ -306,18 +335,35 @@ public class ConvertExcelToCSVProcessor
this.outputStream = outputStream;
}
public void startElement(String uri, String localName, String name,
Attributes attributes) throws SAXException {
if (name.equals(SAX_CELL_REF)) {
String cellType = attributes.getValue(SAX_CELL_TYPE);
// Analyze cell address.
Matcher cellAddressMatcher = CELL_ADDRESS_REGEX.matcher(attributes.getValue(SAX_CELL_ADDRESS));
if (cellAddressMatcher.matches()) {
String col = cellAddressMatcher.group(1);
String row = cellAddressMatcher.group(2);
nextCellAddress = new CellAddress(Integer.parseInt(row), columnToIndex(col));
if (firstCellAddress == null) {
firstCellAddress = nextCellAddress;
}
}
if (cellType != null && cellType.equals(SAX_CELL_STRING)) {
nextIsString = true;
} else {
nextIsString = false;
}
} else if (name.equals(SAX_ROW_REF)) {
if (firstRowLastCellAddress == null) {
firstRowLastCellAddress = previousCellAddress;
}
firstColInRow = true;
previousCellAddress = null;
nextCellAddress = null;
} else if (name.equals(SAX_SHEET_NAME_REF)) {
sheetName = attributes.getValue(0);
}
@ -325,6 +371,16 @@ public class ConvertExcelToCSVProcessor
currentContent = "";
}
private void fillEmptyColumns(int nextColumn) throws IOException {
final CellAddress previousCell = previousCellAddress != null ? previousCellAddress : firstCellAddress;
if (previousCell != null) {
for (int i = 0; i < (nextColumn - previousCell.col); i++) {
// Fill columns.
outputStream.write(",".getBytes());
}
}
}
public void endElement(String uri, String localName, String name)
throws SAXException {
@ -334,29 +390,30 @@ public class ConvertExcelToCSVProcessor
nextIsString = false;
}
if (name.equals(SAX_CELL_CONTENT_REF)) {
if (firstColInRow) {
if (name.equals(SAX_CELL_CONTENT_REF)
// Limit scanning from the first column, and up to the last column.
&& (firstCellAddress == null || firstCellAddress.col <= nextCellAddress.col)
&& (firstRowLastCellAddress == null || nextCellAddress.col <= firstRowLastCellAddress.col)) {
try {
// A cell is found.
fillEmptyColumns(nextCellAddress.col);
firstColInRow = false;
try {
outputStream.write(currentContent.getBytes());
// Keep previously found cell address.
previousCellAddress = nextCellAddress;
} catch (IOException e) {
getLogger().error("IO error encountered while writing content of parsed cell " +
"value from sheet {}", new Object[]{getSheetName()}, e);
}
} else {
try {
outputStream.write(("," + currentContent).getBytes());
} catch (IOException e) {
getLogger().error("IO error encountered while writing content of parsed cell " +
"value from sheet {}", new Object[]{getSheetName()}, e);
}
}
}
if (name.equals(SAX_ROW_REF)) {
//If this is the first row and the end of the row element has been encountered then that means no columns were present.
if (!firstColInRow) {
try {
if (firstRowLastCellAddress != null) {
fillEmptyColumns(firstRowLastCellAddress.col);
}
rowCount++;
outputStream.write("\n".getBytes());
} catch (IOException e) {

97
nifi-nar-bundles/nifi-poi-bundle/nifi-poi-processors/src/main/resources/docs/org.apache.nifi.processors.poi.ConvertExcelToCSVProcessor/additionalDetails.html Normal file
View File

@ -0,0 +1,97 @@
<!DOCTYPE html>
<html lang="en">
<!--
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.
-->
<head>
<meta charset="utf-8" />
<title>ConvertExcelToCSVProcessor</title>
<style>
table {
border-collapse: collapse;
}
table, th, td {
border: 1px solid #ccc;
}
td.r {
text-align: right;
}
td {
width: 50px;
padding: 5px;
}
</style>
<link rel="stylesheet" href="../../../../../css/component-usage.css" type="text/css" />
</head>
<body>
<h2>How it extracts CSV data from a sheet</h2>
<p>
ConvertExcelToCSVProcessor extracts CSV data with following rules:
</p>
<ul>
<li>Find the fist cell which has a value in it (the FirstCell).</li>
<li>Scan cells in the first row, starting from the FirstCell,
until it reaches to a cell after which no cell with a value can not be found in the row (the FirstRowLastCell).</li>
<li>Process the 2nd row and later, from the column of FirstCell to the column of FirstRowLastCell.</li>
<li>If a row does not have any cell that has a value, then the row is ignored.</li>
</ul>
<p>
As an example, the sheet shown below will be:
</p>
<table>
<tbody>
<tr><th>row </th><th>A</th><th>B</th><th>C</th><th>D</th><th>E</th><th>F</th><th>G</th></tr>
<tr><td class="r"> 1</td><td> </td><td> </td><td> </td><td> </td><td> </td><td> </td><td> </td></tr>
<tr><td class="r"> 2</td><td> </td><td> </td><td>x</td><td>y</td><td>z</td><td> </td><td> </td></tr>
<tr><td class="r"> 3</td><td> </td><td> </td><td>1</td><td> </td><td> </td><td> </td><td> </td></tr>
<tr><td class="r"> 4</td><td>2</td><td> </td><td> </td><td>3</td><td> </td><td> </td><td> </td></tr>
<tr><td class="r"> 5</td><td> </td><td> </td><td> </td><td> </td><td>4</td><td> </td><td> </td></tr>
<tr><td class="r"> 6</td><td> </td><td> </td><td>5</td><td>6</td><td>7</td><td> </td><td> </td></tr>
<tr><td class="r"> 7</td><td> </td><td> </td><td> </td><td> </td><td> </td><td>8</td><td> </td></tr>
<tr><td class="r"> 8</td><td> </td><td> </td><td> </td><td> </td><td> </td><td> </td><td> </td></tr>
<tr><td class="r"> 9</td><td> </td><td> </td><td> </td><td> </td><td>9</td><td> </td><td> </td></tr>
<tr><td class="r"> 10</td><td> </td><td> </td><td> </td><td> </td><td> </td><td> </td><td> </td></tr>
<tr><td class="r"> 11</td><td> </td><td> </td><td> </td><td> </td><td> </td><td> </td><td> </td></tr>
</tbody>
</table>
<p>
converted to following CSV:
</p>
<pre>
x,y,z
1,,
,3,
,,4
5,6,7
,,9
</pre>
<ul>
<li>C2(x) is the FirstCell, and E2(z) is the FirstRowLastCell.</li>
<li>A4(2) is ignored because it is out of range. So is F7(8).</li>
<li>Row 7 and 8 are ignored because those do not have a valid cell.</li>
<li>It is important to have a header row as shown in the example to define data area,
especially when a sheet includes empty cells.</li>
</ul>
</body>
</html>

36
nifi-nar-bundles/nifi-poi-bundle/nifi-poi-processors/src/test/java/org/apache/nifi/processors/poi/ConvertExcelToCSVProcessorTest.java
View File

@ -16,9 +16,11 @@
*/
package org.apache.nifi.processors.poi;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import java.io.File;
import java.nio.charset.StandardCharsets;
import java.util.List;
import org.apache.nifi.flowfile.attributes.CoreAttributes;
@ -39,6 +41,16 @@ public class ConvertExcelToCSVProcessorTest {
testRunner = TestRunners.newTestRunner(ConvertExcelToCSVProcessor.class);
}
@Test
public void testColToIndex() {
assertEquals(Integer.valueOf(0), ConvertExcelToCSVProcessor.columnToIndex("A"));
assertEquals(Integer.valueOf(1), ConvertExcelToCSVProcessor.columnToIndex("B"));
assertEquals(Integer.valueOf(25), ConvertExcelToCSVProcessor.columnToIndex("Z"));
assertEquals(Integer.valueOf(29), ConvertExcelToCSVProcessor.columnToIndex("AD"));
assertEquals(Integer.valueOf(239), ConvertExcelToCSVProcessor.columnToIndex("IF"));
assertEquals(Integer.valueOf(16383), ConvertExcelToCSVProcessor.columnToIndex("XFD"));
}
@Test
public void testMultipleSheetsGeneratesMultipleFlowFiles() throws Exception {
@ -149,6 +161,30 @@ public class ConvertExcelToCSVProcessorTest {
testRunner.assertTransferCount(ConvertExcelToCSVProcessor.FAILURE, 0);
}
/**
* Validates that a sheet contains blank cells can be converted to a CSV without missing columns.
*
* @throws Exception
* Any exception thrown during execution.
*/
@Test
public void testProcessASheetWithBlankCells() throws Exception {
testRunner.setProperty(ConvertExcelToCSVProcessor.DESIRED_SHEETS, "Sheet1");
testRunner.enqueue(new File("src/test/resources/with-blank-cells.xlsx").toPath());
testRunner.run();
testRunner.assertTransferCount(ConvertExcelToCSVProcessor.SUCCESS, 1);
testRunner.assertTransferCount(ConvertExcelToCSVProcessor.ORIGINAL, 1);
testRunner.assertTransferCount(ConvertExcelToCSVProcessor.FAILURE, 0);
MockFlowFile ff = testRunner.getFlowFilesForRelationship(ConvertExcelToCSVProcessor.SUCCESS).get(0);
Long l = new Long(ff.getAttribute(ConvertExcelToCSVProcessor.ROW_NUM));
assertTrue(l == 8l);
ff.isContentEqual("test", StandardCharsets.UTF_8);
ff.assertContentEquals(new File("src/test/resources/with-blank-cells.csv"));
}
/**
* Tests for graceful handling and error messaging of unsupported .XLS files.
*/

8
nifi-nar-bundles/nifi-poi-bundle/nifi-poi-processors/src/test/resources/with-blank-cells.csv Normal file
View File

@ -0,0 +1,8 @@
A,B,C,D
A1,,,
,B2,C2,
,,C3,
,,C4,D4
A5,,C5,D5
A6,B6,,D6
A7,B7,C7,D7
1 A B C D
2 A1
3 B2 C2
4 C3
5 C4 D4
6 A5 C5 D5
7 A6 B6 D6
8 A7 B7 C7 D7

BIN
nifi-nar-bundles/nifi-poi-bundle/nifi-poi-processors/src/test/resources/with-blank-cells.xlsx Normal file
View File

Binary file not shown.