maven:
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.8</version>
</dependency>
<dependency>
<groupId>xerces</groupId>
<artifactId>xercesImpl</artifactId>
<version>2.10.0</version>
</dependency>
代码:读取26M excel 2007 xlsx,43万记录,耗时25s (jvm: -Xmx1024M)
import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import org.apache.poi.hssf.usermodel.HSSFDateUtil;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.xssf.eventusermodel.XSSFReader;
import org.apache.poi.xssf.model.SharedStringsTable;
import org.apache.poi.xssf.usermodel.XSSFRichTextString;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.helpers.XMLReaderFactory;
public class XSSFProcess {
public static void main1(String[] args) throws Exception {
System.out.println();
long end, start = System.currentTimeMillis();
// Path file = Paths.get("/home/skzrorg/tmp/2007.xlsx");
Path file = Paths.get("/home/skzrorg/tmp/xlsx/IPTABLE.xlsx");
SheetDatasHandler handler = UtilPoi.read(file);
end = System.currentTimeMillis();
System.out.println("耗时:" + (end - start) / 1000f + "s");
List<List<Object>> sheet = handler.getSheetData(0);
System.out.println("sheet 大小:" + sheet.size());
System.out.println("sheet[0]" + sheet.get(0));
int i = new Random().nextInt(sheet.size());
System.out.println("sheet[" + i + "]" + sheet.get(i));
System.out.println("sheet[" + (sheet.size() - 1) + "]" + sheet.get(sheet.size() - 1));
}
private static int rowCount;
public static void main(String[] args) throws Exception {
System.out.println();
long end, start = System.currentTimeMillis();
Path file = Paths.get("/home/skzrorg/tmp/xlsx/IPTABLE.xlsx");
UtilPoi.read(file, new RowMapper() {
@Override
void mapRow(int sheetIndex, int rowIndex, List<Object> row) {
rowCount++;
}
});
end = System.currentTimeMillis();
System.out.println("耗时:" + (end - start) / 1000f + "s");
System.out.println("sheet 大小:" + rowCount);
}
}
class UtilPoi {
public static SheetDatasHandler read(Path file) throws Exception {
SheetDatasHandler handler = new SheetDatasHandler((int) (Files.size(file) / 50));
read(file, handler);
return handler;
}
public static void read(Path file, RowMapper mapper) throws Exception {
final long size = Files.size(file);
try (InputStream in = new BufferedInputStream(new FileInputStream(file.toFile()), size > Integer.MAX_VALUE ? 1024 * 1024 * 10 : (int) size)) {
read(in, mapper);
}
}
public static void read(InputStream in, RowMapper mapper) throws Exception {
XSSFReader reader = new XSSFReader(OPCPackage.open(in));
XMLReader parser = XMLReaderFactory.createXMLReader("org.apache.xerces.parsers.SAXParser");
mapper.setSharedStringsTable(reader.getSharedStringsTable());
parser.setContentHandler(mapper);
for (Iterator<InputStream> iter = reader.getSheetsData(); iter.hasNext();) {
try (InputStream sheetIn = iter.next()) {
parser.parse(new InputSource(sheetIn));
}
}
}
}
class SheetDatasHandler extends RowMapper {
private int bufRowSize, curSheetIndex = -1;
private List<List<List<Object>>> sheetDatas = new ArrayList<>();
private List<List<Object>> sheetData;
public List<List<List<Object>>> getSheetDatas() {
return sheetDatas;
}
public List<List<Object>> getSheetData(int sheetIndex) {
return sheetDatas.get(sheetIndex);
}
SheetDatasHandler(int bufRowSize) {
this.bufRowSize = bufRowSize;
}
@Override
void mapRow(int sheetIndex, int rowIndex, List<Object> row) {
if (curSheetIndex != sheetIndex) {
sheetData = new ArrayList<>(sheetIndex == 0 ? bufRowSize : sheetData.size() / 2);
sheetDatas.add(sheetData);
curSheetIndex = sheetIndex;
}
sheetData.add(row);
}
}
abstract class RowMapper extends DefaultHandler {
private SharedStringsTable sst;
private Map<Integer, String> strMap;
private int sheetIndex = -1, rowIndex = -1;
private List<Object> row;
private String cellS;
private String cellType;
private boolean valueFlag;
private StringBuilder value;
public void setSharedStringsTable(SharedStringsTable sst) {
this.sst = sst;
strMap = new HashMap<>(sst.getCount());
}
private void clearSheet() {
sst = null;
strMap = null;
row = null;
cellS = null;
cellType = null;
value = null;
rowIndex = 0;
}
private Object convertCellValue() {
String tmp = value.toString();
Object result = tmp;
if ("s".equals(cellType)) { //字符串
Integer key = Integer.parseInt(tmp);
result = strMap.get(key);
if (result == null) strMap.put(key, (String) (result = new XSSFRichTextString(sst.getEntryAt(key)).toString()));
} else if ("n".equals(cellType)) {
if ("2".equals(cellS)) { //日期
result = HSSFDateUtil.getJavaDate(Double.valueOf(tmp));
}
}
return result;
}
@Override
public void startElement(String uri, String localName, String name, Attributes attributes) throws SAXException {
if ("sheetData".equals(name)) {
sheetIndex++;
} else if ("row".equals(name)) {
rowIndex++;
row = new ArrayList<>();
} else if ("c".equals(name)) {
cellS = attributes.getValue("s");
cellType = attributes.getValue("t");
} else if ("v".equals(name)) {
valueFlag = true;
value = new StringBuilder();
}
}
@Override
public void endElement(String uri, String localName, String name) throws SAXException {
if ("sheetData".equals(name)) {
clearSheet();
} else if ("row".equals(name)) {
mapRow(sheetIndex, rowIndex, row);
} else if ("v".equals(name)) {
row.add(convertCellValue());
valueFlag = false;
}
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
if (valueFlag) value.append(ch, start, length);
}
abstract void mapRow(int sheetIndex, int rowIndex, List<Object> row);
}
如果采用dom解析,需要配置2G内存
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