系统需要用到一个导入excel文件的功能，使用poi组件常规方式读取excel时，内存耗尽，OutOfMemoryError,或者读取非常慢
所以写了一个工具类，使用poi sax方式读取excel，速度快很多，内存消耗可以接受。
测试结果如下：
.xlsx文件，35M大小，总4个sheel，
只读取第一个，37434行，54列
总行数：37434
读取耗时：39秒
打印耗时：17秒
主要代码如下：
ExcelUtils.class 主入口
package com.xxx.bi.utils.excel;
import java.util.List;
import java.util.Objects;
import org.apache.commons.lang3.StringUtils;
import com.google.common.collect.Lists;
public class ExcelUtils {
/** logger日志. */
// public static final Logger LOGGER = Logger.getLogger(ExcelUtils.class);
public ExcelUtils() {
}
/**
* 获取excel的表头
*
* @param filePath
* 文件路径
* @param headerNum
* 表头所在行数
* @return
*/
public static List getHeader(String filePath, int headerNum) {
if (StringUtils.isBlank(filePath)) {
throw new IllegalArgumentException("传入文件路径不能为空");
}
if (Objects.isNull(headerNum) || headerNum < 1) {
headerNum = 1;
}
try {
return LargeExcelFileReadUtil.getRowFromSheetOne(filePath, headerNum);
} catch (Exception e) {
// LOGGER.info("获取excel[" + filePath + "]表头失败，原因:", e);
e.printStackTrace();
}
return Lists.newArrayList();
}
/**
* 获取excel的所有数据
* 所有数据类型都是String
* 会以第一行数据的列数为总列数，所以第一行的数据必须都不为空，否则可能出java.lang.IndexOutOfBoundsException
*
* @param filePath
* 文件路径
* @param headerNum
* 表头所在行数
* @return
*/
public static List> getAllData(String filePath) {
if (StringUtils.isBlank(filePath)) {
throw new IllegalArgumentException("传入文件路径不能为空");
}
try {
return LargeExcelFileReadUtil.getRowsFromSheetOne(filePath);
} catch (Exception e) {
// LOGGER.info("获取excel[" + filePath + "]表头失败，原因:", e);
e.printStackTrace();
}
return Lists.newArrayList();
}
public static void main(String[] args) {
long start = System.currentTimeMillis();
String filepath = "C:/Users/Administrator/Desktop/05-作业调配表 -快递.xlsx";
// List result = ExcelUtils.getHeader(filepath, 1);
// for (String col : result) {
// System.out.println(col);
// }
List> result = ExcelUtils.getAllData(filepath);
long end = System.currentTimeMillis();
for (List list : result) {
System.out.println(list.toString());
}
long end1 = System.currentTimeMillis();
try {
Thread.sleep(1000l);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.err.println("总行数：" + result.size());
System.err.println(("读取耗时：" + (end - start) / 1000) + "秒");
System.err.println(("打印耗时：" + (end1 - end) / 1000) + "秒");
}
}
LargeExcelFileReadUtil.class 真正的工具类
package com.xxx.bi.utils.excel;
import java.io.InputStream;
import java.util.List;
import java.util.Objects;
import org.apache.log4j.Logger;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.xssf.eventusermodel.XSSFReader;
import org.apache.poi.xssf.model.SharedStringsTable;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;
public class LargeExcelFileReadUtil {
/** logger日志. */
public static final Logger LOGGER = Logger.getLogger(LargeExcelFileReadUtil.class);
// 处理一个sheet
public static List getRowFromSheetOne(String filename, Integer rowNum) throws Exception {
InputStream inputStream = null;
OPCPackage pkg = null;
SingleRowHandler singleRowHandler = null;
try {
pkg = OPCPackage.open(filename);
XSSFReader r = new XSSFReader(pkg);
SharedStringsTable sst = r.getSharedStringsTable();
singleRowHandler = new SingleRowHandler(sst, rowNum);
XMLReader parser = XMLReaderFactory.createXMLReader("com.sun.org.apache.xerces.internal.parsers.SAXParser");
parser.setContentHandler(singleRowHandler);
inputStream = r.getSheet("rId1");
InputSource sheetSource = new InputSource(inputStream);
parser.parse(sheetSource);
return singleRowHandler.getRow();
} catch (Exception e) {
String message = e.getMessage();
if (Objects.nonNull(rowNum) && Objects.nonNull(singleRowHandler)
&& SingleRowHandler.FINISH_ROW_MESSAGE.equalsIgnoreCase(message)) {
// 获取某一行数据完成 ，暂时不知道怎么能终止excel解析，直接抛出了异常，实际是成功的
return singleRowHandler.getRow();
}
throw e;
} finally {
if (Objects.nonNull(pkg)) {
pkg.close();
}
if (Objects.nonNull(inputStream)) {
inputStream.close();
}
}
}
// 处理一个sheet
public static List> getRowsFromSheetOne(String filename) throws Exception {
InputStream inputStream = null;
OPCPackage pkg = null;
MultiRowHandler multiRowHandler = null;
try {
pkg = OPCPackage.open(filename);
XSSFReader r = new XSSFReader(pkg);
SharedStringsTable sst = r.getSharedStringsTable();
multiRowHandler = new MultiRowHandler(sst);
XMLReader parser = XMLReaderFactory.createXMLReader("com.sun.org.apache.xerces.internal.parsers.SAXParser");
parser.setContentHandler(multiRowHandler);
inputStream = r.getSheet("rId1");
InputSource sheetSource = new InputSource(inputStream);
parser.parse(sheetSource);
return multiRowHandler.getRows();
} catch (Exception e) {
throw e;
} finally {
if (Objects.nonNull(pkg)) {
pkg.close();
}
if (Objects.nonNull(inputStream)) {
inputStream.close();
}
}
}
} SingleRowHandler.class 当行处理类，可以只获取表头或表格中的某一行数据
package com.xxx.bi.utils.excel;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.regex.Pattern;
import org.apache.poi.xssf.model.SharedStringsTable;
import org.apache.poi.xssf.usermodel.XSSFRichTextString;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class SingleRowHandler extends DefaultHandler {
public final static String FINISH_ROW_MESSAGE = "row data process finish";
private Integer rowNum = null;// rowNum不为空时则标示只需要获取这一行的数据
private int curRowNum = 1;
private String cellType = "";
private SharedStringsTable sst;
private String lastContents;
private boolean nextIsString;
private String cellPosition;
private List row = new ArrayList<>();
public List getRow() {
return row;
}
public SingleRowHandler(SharedStringsTable sst, Integer rowNum) {
this.sst = sst;
this.rowNum = rowNum;
}
public void startElement(String uri, String localName, String name, Attributes attributes) throws SAXException {
if (name.equals("c")) {
cellPosition = attributes.getValue("r");
// 这是一个新行
if (Pattern.compile("^A[0-9]+$").matcher(cellPosition).find()) {
curRowNum = Integer.valueOf(cellPosition.substring(1));
}
cellType = "";
cellType = attributes.getValue("t");
if ("s".equals(cellType)) {
nextIsString = true;
} else {
nextIsString = false;
}
}
// 清楚缓存内容
lastContents = "";
if (Objects.nonNull(rowNum) && curRowNum > rowNum) {
// 获取某一行数据完成 ，暂时不知道怎么能终止excel解析，直接抛出了异常，实际是成功的
throw new SAXException(FINISH_ROW_MESSAGE);
}
}
public void endElement(String uri, String localName, String name) throws SAXException {
if (nextIsString) {
int idx = Integer.parseInt(lastContents);
lastContents = new XSSFRichTextString(sst.getEntryAt(idx)).toString();
nextIsString = false;
}
if (name.equals("v")) {
if (Objects.isNull(rowNum) || rowNum == curRowNum) {
row.add(lastContents);
}
}
}
public void characters(char[] ch, int start, int length) throws SAXException {
lastContents += new String(ch, start, length);
}
} MultiRowHandler.class 获取excel所有行的数据
package com.xxx.bi.utils.excel;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.regex.Pattern;
import org.apache.commons.lang3.StringUtils;
import org.apache.poi.xssf.model.SharedStringsTable;
import org.apache.poi.xssf.usermodel.XSSFRichTextString;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
/**
* 获取完整excel数据的handler
*
* @author Administrator
*
*/
public class MultiRowHandler extends DefaultHandler {
private int curRowNum = 0;// 行号，从1开始
private int curColIndex = -1;// 列索引，从0开始
private int colCnt = 0;// 列数，取第一行列数做为列总数
private String cellType = "";
private SharedStringsTable sst;
private String lastContents;
private boolean nextIsString;
private String cellPosition;
private List head = null;
private List curRowData = null;
private boolean curRowIsBlank = true;// 当前是个空行
private List> rows = new ArrayList<>();
public List> getRows() {
return rows;
}
public MultiRowHandler(SharedStringsTable sst) {
this.sst = sst;
}
@Override
public void startElement(String uri, String localName, String name, Attributes attributes) throws SAXException {
if (name.equals("c")) {
cellPosition = attributes.getValue("r");
curColIndex = getColIndex(cellPosition);
// 这是一个新行
if (isNewRow(cellPosition)) {
curRowNum = getRowNum(cellPosition);
if (2 == curRowNum && Objects.nonNull(curRowData)) {
head = curRowData;
colCnt = head.size();
}
curRowData = getBlankRow(colCnt);
}
cellType = "";
cellType = attributes.getValue("t");
if ("s".equals(cellType)) {
nextIsString = true;
} else {
nextIsString = false;
}
}
// 清楚缓存内容
lastContents = "";
}
private boolean isNewRow(String cellPosition) {
// 坐标以A开头，后面跟数字 或者坐标行和当前行不一致的
boolean newRow = Pattern.compile("^A[0-9]+$").matcher(cellPosition).find();
if (!newRow) {
int cellRowNum = getRowNum(cellPosition);
newRow = (cellRowNum != curRowNum);
}
return newRow;
}
/**
* 根据列坐标获取行号，从1开始，返回0时标示出错
*
* @param cellPosition
* 列坐标，为A1,B23等
* @return 行号，从1开始，返回0是为失败
*/
private static int getRowNum(String cellPosition) {
String strVal = Pattern.compile("[^0-9]").matcher(cellPosition).replaceAll("").trim();// 获取坐标中的数字
if (StringUtils.isNotBlank(strVal)) {
return Integer.valueOf(strVal);
}
return 0;
}
/**
* 根据列坐标返回当前列索引，从0开始，返回-1时标示出错
* A1->0; B1->1...AA1->26
*
* @param cellPosition
* 列坐标，为A1,B23等
* @return 列索引，从0开始，返回-1是为失败,A1->0; B1->1...AA1->26
*/
private static int getColIndex(String cellPosition) {
int index = -1;
int num = 65;// A的Unicode码
int length = cellPosition.length();
for (int i = 0; i < length; i++) {
char c = cellPosition.charAt(i);
if (Character.isDigit(c)) {
break;// 确定指定的char值是否为数字
}
index = (index + 1) * 26 + (int) c - num;
}
return index;
}
/**
* 返回一个全部为空字符串的空行
*
* @param cnt
* @return
*/
private List getBlankRow(int cnt) {
List result = new ArrayList<>(cnt);
for (int i = 0; i < cnt; i++) {
result.add(i, "");
}
curRowIsBlank = true;
return result;
}
@Override
public void endElement(String uri, String localName, String name) throws SAXException {
if (nextIsString) {
int idx = Integer.parseInt(lastContents);
lastContents = new XSSFRichTextString(sst.getEntryAt(idx)).toString();
nextIsString = false;
}
if (name.equals("v")) {
// System.out.println(MessageFormat.format("当前列定位:{0},当前行:{1},当前列:{2},当前值:{3}",
// cellPosition, curRowNum,
// curColIndex, lastContents));
if (Objects.isNull(head)) {
curRowData.add(lastContents);
} else {
curRowData.set(curColIndex, lastContents);
}
curRowIsBlank = false;
// 这是一个新行
if (isNewRow(cellPosition)) {
if (Objects.nonNull(curRowData)) {
if (curRowIsBlank) {
curRowData.clear();// 如果当前行是空行，则清空当前行数据
}
rows.add(curRowData);
}
}
}
}
@Override
public void endDocument() throws SAXException {
if (Objects.nonNull(curRowData) && !curRowIsBlank) {
rows.add(curRowData);// 最后一行在上面不好加入,最后一行全是空行的不加入
}
super.endDocument();
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
lastContents += new String(ch, start, length);
}
@Override
public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException {
lastContents += "";
}
public static void main(String[] args) {
System.out.println(getColIndex("BC2"));
}
}