[英]How to read big .xls files in java?
10在Java中读取xls文件。
但是,当我打算读取20 MB以上的大型.xls文件时,这给了我错误。
以下我的代码对于.xls小文件正常运行,但是对于.xls大文件却给出了Java堆错误。 Java代码
public static void main(String[] args) throws IOException {
ArrayList<ArrayList<String>> Temp = new ArrayList<ArrayList<String>>();
ArrayList<String> Temp1 = new ArrayList<String>();
int row = 0;
String fname = "D:/Vijay/xls/vijay/bookTest.xls";
try {
InputStream fis = new FileInputStream(fname);
HSSFWorkbook workbook = new HSSFWorkbook(fis);
HSSFSheet sheet = workbook.getSheetAt(0);
FormulaEvaluator formulaEval = workbook.getCreationHelper().createFormulaEvaluator();
int rowEnd = sheet.getLastRowNum();
int rowStart = sheet.getFirstRowNum();
for (int rowNum = rowStart; rowNum < rowEnd; rowNum++) {
Row r = sheet.getRow(rowNum);
int lastColumn = r.getLastCellNum();
int cols = 0;
Temp1 = new ArrayList<String>();
for (int cn = 0; cn < lastColumn; cn++) {
String cellvalue = "";
Cell c = r.getCell(cn, Row.RETURN_BLANK_AS_NULL);
if (c == null) {
cellvalue = "";
} else {
if (r.getCell(cn).getCellType() == HSSFCell.CELL_TYPE_STRING) {
cellvalue = r.getCell(cn).getStringCellValue();
} else if (r.getCell(cn).getCellType() == HSSFCell.CELL_TYPE_NUMERIC) {
if (HSSFDateUtil.isCellDateFormatted(r.getCell(cn))) {
DateFormat formatter = new SimpleDateFormat(
"E MMM dd HH:mm:ss Z yyyy");
Date date = (Date) formatter.parse(r
.getCell(cn).getDateCellValue()
.toString());
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cellvalue = cal.get(Calendar.DATE) + "/"
+ (cal.get(Calendar.MONTH) + 1) + "/"
+ cal.get(Calendar.YEAR);
} else {
r.getCell(cn).setCellType(
r.getCell(cn).CELL_TYPE_STRING);
cellvalue = ""
+ r.getCell(cn).getStringCellValue();
}
} else if (r.getCell(cn).getCellType() == HSSFCell.CELL_TYPE_BOOLEAN) {
cellvalue = ""
+ r.getCell(cn).getBooleanCellValue();
} else if (r.getCell(cn).getCellType() == HSSFCell.CELL_TYPE_FORMULA) {
cellvalue = ""
+ formulaEval.evaluate(r.getCell(cn))
.formatAsString();
}
}
Temp1.add(cols, cellvalue);
cols++;
}
if (Temp1.size() > 0) {
Temp.add(row, Temp1);
row++;
}
}
for (ArrayList al : Temp) {
System.out.println("Contents of temp " + al);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
错误-
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at java.util.LinkedHashMap.createEntry(Unknown Source)
at java.util.LinkedHashMap.addEntry(Unknown Source)
at java.util.HashMap.put(Unknown Source)
at sun.util.resources.OpenListResourceBundle.loadLookup(Unknown Source)
at sun.util.resources.OpenListResourceBundle.loadLookupTablesIfNecessary(Unknown Source)
at sun.util.resources.OpenListResourceBundle.handleGetObject(Unknown Source)
at sun.util.resources.TimeZoneNamesBundle.handleGetObject(Unknown Source)
at java.util.ResourceBundle.getObject(Unknown Source)
at java.util.ResourceBundle.getObject(Unknown Source)
at java.util.ResourceBundle.getStringArray(Unknown Source)
at sun.util.TimeZoneNameUtility.retrieveDisplayNames(Unknown Source)
at sun.util.TimeZoneNameUtility.retrieveDisplayNames(Unknown Source)
at java.util.TimeZone.getDisplayNames(Unknown Source)
at java.util.TimeZone.getDisplayName(Unknown Source)
at java.util.Date.toString(Unknown Source)
at com.test.arrayList.ValidateXls.main(ValidateXls.java:69)
请帮助我解决此问题,或建议我另一种方法来读取Java中的.xls大文件。
提前致谢。
我认为您需要尝试的第一件事是增加Java默认堆空间。 例如:-Xms256m -Xmx512m -XX:PermSize = 64M -XX:MaxPermSize = 1000M
您还需要根据poi文档将文件的加载更改为这样(WorkbookFactory.create(new File(“ MyExcel.xls”))),请参见此链接
http://poi.apache.org/spreadsheet/quick-guide.html#FileInputStream
文件与InputStreams
打开工作簿(.xls HSSFWorkbook或.xlsx XSSFWorkbook)时,可以从文件或InputStream加载工作簿。 使用File对象可以减少内存消耗,而InputStream则需要更多内存,因为它必须缓冲整个文件。
如果使用WorkbookFactory,则使用其中一个非常容易:
//使用文件Workbook wb = WorkbookFactory.create(new File(“ MyExcel.xls”));
//使用InputStream,需要更多的内存Workbook wb = WorkbookFactory.create(new FileInputStream(“ MyExcel.xlsx”));;
如果仍然遇到相同的异常,请尝试使用
XSSF和SAX(事件API)
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