读入Excel大文件解决方法
官方例子
package cn.com.ftms.utils;
import org.apache.poi.openxml4j.exceptions.OpenXML4JException;
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import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.poi.openxml4j.exceptions.OpenXML4JException;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.openxml4j.opc.PackageAccess;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.util.CellAddress;
import org.apache.poi.ss.util.CellReference;
import org.apache.poi.util.SAXHelper;
import org.apache.poi.xssf.eventusermodel.ReadOnlySharedStringsTable;
import org.apache.poi.xssf.eventusermodel.XSSFReader;
import org.apache.poi.xssf.eventusermodel.XSSFSheetXMLHandler;
import org.apache.poi.xssf.eventusermodel.XSSFSheetXMLHandler.SheetContentsHandler;
import org.apache.poi.xssf.extractor.XSSFEventBasedExcelExtractor;
import org.apache.poi.xssf.model.StylesTable;
import org.apache.poi.xssf.usermodel.XSSFComment;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
/**
* A rudimentary XLSX -> CSV processor modeled on the
* POI sample program XLS2CSVmra from the package
* org.apache.poi.hssf.eventusermodel.examples.
* As with the HSSF version, this tries to spot missing
* rows and cells, and output empty entries for them.
* <p/>
* Data sheets are read using a SAX parser to keep the
* memory footprint relatively small, so this should be
* able to read enormous workbooks. The styles table and
* the shared-string table must be kept in memory. The
* standard POI styles table class is used, but a custom
* (read-only) class is used for the shared string table
* because the standard POI SharedStringsTable grows very
* quickly with the number of unique strings.
* <p/>
* For a more advanced implementation of SAX event parsing
* of XLSX files, see {@link XSSFEventBasedExcelExtractor}
* and {@link XSSFSheetXMLHandler}. Note that for many cases,
* it may be possible to simply use those with a custom
* {@link SheetContentsHandler} and no SAX code needed of
* your own!
*/
public class XLSX2CSV {
/**
* Uses the XSSF Event SAX helpers to do most of the work
* of parsing the Sheet XML, and outputs the contents
* as a (basic) CSV.
*/
private class SheetToCSV implements SheetContentsHandler {
private boolean firstCellOfRow = false;
private int currentRow = -1;
private int currentCol = -1;
private void outputMissingRows(int number) {
for (int i = 0; i < number; i++) {
for (int j = 0; j < minColumns; j++) {
output.append(',');
}
output.append('\n');
}
}
@Override
public void startRow(int rowNum) {
// If there were gaps, output the missing rows
outputMissingRows(rowNum - currentRow - 1);
// Prepare for this row
firstCellOfRow = true;
currentRow = rowNum;
currentCol = -1;
}
@Override
public void endRow(int rowNum) {
// Ensure the minimum number of columns
for (int i = currentCol; i < minColumns; i++) {
output.append(',');
}
output.append('\n');
}
@Override
public void cell(String cellReference, String formattedValue,
XSSFComment comment) {
if (firstCellOfRow) {
firstCellOfRow = false;
} else {
output.append(',');
}
// gracefully handle missing CellRef here in a similar way as XSSFCell does
if (cellReference == null) {
cellReference = new CellAddress(currentRow, currentCol).formatAsString();
}
// Did we miss any cells?
int thisCol = (new CellReference(cellReference)).getCol();
int missedCols = thisCol - currentCol - 1;
for (int i = 0; i < missedCols; i++) {
output.append(',');
}
currentCol = thisCol;
// Number or string?
try {
Double.parseDouble(formattedValue);
output.append(formattedValue);
} catch (NumberFormatException e) {
output.append('"');
output.append(formattedValue);
output.append('"');
}
}
@Override
public void headerFooter(String text, boolean isHeader, String tagName) {
// Skip, no headers or footers in CSV
}
}
///////////////////////////////////////
private final OPCPackage xlsxPackage;
/**
* Number of columns to read starting with leftmost
*/
private final int minColumns;
/**
* Destination for data
*/
private final PrintStream output;
/**
* Creates a new XLSX -> CSV converter
*
* @param pkg The XLSX package to process
* @param output The PrintStream to output the CSV to
* @param minColumns The minimum number of columns to output, or -1 for no minimum
*/
public XLSX2CSV(OPCPackage pkg, PrintStream output, int minColumns) {
this.xlsxPackage = pkg;
this.output = output;
this.minColumns = minColumns;
}
/**
* Parses and shows the content of one sheet
* using the specified styles and shared-strings tables.
*
* @param styles
* @param strings
* @param sheetInputStream
*/
public void processSheet(
StylesTable styles,
ReadOnlySharedStringsTable strings,
SheetContentsHandler sheetHandler,
InputStream sheetInputStream)
throws IOException, ParserConfigurationException, SAXException {
DataFormatter formatter = new DataFormatter();
InputSource sheetSource = new InputSource(sheetInputStream);
try {
XMLReader sheetParser = SAXHelper.newXMLReader();
ContentHandler handler = new XSSFSheetXMLHandler(
styles, null, strings, sheetHandler, formatter, false);
sheetParser.setContentHandler(handler);
sheetParser.parse(sheetSource);
} catch (ParserConfigurationException e) {
throw new RuntimeException("SAX parser appears to be broken - " + e.getMessage());
}
}
/**
* Initiates the processing of the XLS workbook file to CSV.
*
* @throws IOException
* @throws OpenXML4JException
* @throws ParserConfigurationException
* @throws SAXException
*/
public void process()
throws IOException, OpenXML4JException, ParserConfigurationException, SAXException {
ReadOnlySharedStringsTable strings = new ReadOnlySharedStringsTable(this.xlsxPackage);
XSSFReader xssfReader = new XSSFReader(this.xlsxPackage);
StylesTable styles = xssfReader.getStylesTable();
XSSFReader.SheetIterator iter = (XSSFReader.SheetIterator) xssfReader.getSheetsData();
int index = 0;
while (iter.hasNext()) {
InputStream stream = iter.next();
String sheetName = iter.getSheetName();
this.output.println();
this.output.println(sheetName + " [index=" + index + "]:");
processSheet(styles, strings, new SheetToCSV(), stream);
stream.close();
++index;
}
}
public static void main(String[] args) throws Exception {
/* if (args.length < 1) {
System.err.println("Use:");
System.err.println(" XLSX2CSV <xlsx file> [min columns]");
return;
}*/
File xlsxFile = new File("F:\\8月数据.xlsx");
if (!xlsxFile.exists()) {
System.err.println("Not found or not a file: " + xlsxFile.getPath());
return;
}
int minColumns = -1;
if (args.length >= 2)
minColumns = Integer.parseInt(args[1]);
// The package open is instantaneous, as it should be.
OPCPackage p = OPCPackage.open(xlsxFile.getPath(), PackageAccess.READ);
XLSX2CSV xlsx2csv = new XLSX2CSV(p, System.out, minColumns);
xlsx2csv.process();
p.close();
}
}
