java如何读取大xlsx文件呢?

下文笔者讲述xlsx文件的方法分享,如下所示

今天使用apache-POI中的XSSF读取xlsx文件
    将出现
     java.lang.OutOfMemoryError: Java heap space
      将堆调大
         -Xmx1024m 为 java 类增加了堆大小 仍然报错 

        String filename ="D:\\\\test.xlsx";
        FileInputStream fis = null;
        try {
        fis = new FileInputStream(filename);
        XSSFWorkbook workbook = new XSSFWorkbook(fis);
        }

解决此类问题，我们只需将文件作为POIFSFileSystem对象
然后再对文件进行操作 例:

String pass ="secret";
File file = new File("data/test.xlsx");
   
try (POIFSFileSystem fs = new POIFSFileSystem(file);
   // wrap in org.apache.poi.poifs.filesystem.DocumentFactoryHelper.getDecryptedStream
   InputStream in = DocumentFactoryHelper.getDecryptedStream(fs, pass);
   OPCPackage pkg = OPCPackage.open(in))
{
    XSSFReader reader = new XSSFReader(pkg);
       
    StylesTable styles = reader.getStylesTable();
    ReadOnlySharedStringsTable sharedStrings = new ReadOnlySharedStringsTable(pkg);
    SheetContentsHandler f = new SheetContentsHandler() {
       // ... your implementation of SheetContentsHandler interface ...
    };
    ContentHandler handler = new XSSFSheetXMLHandler(styles, sharedStrings, f, true);
    XMLReader parser = XMLReaderFactory.createXMLReader();
    parser.setContentHandler(handler);
    parser.parse(new InputSource(reader.getSheetsData().next()));
}