使用POI写入xls以获取大量数据并在需要时创建新工作簿

Question

我有代码写入xls文件usng POI，但是我得到的输入可能会得到很多行，因此它可能会超出工作簿的最大大小。 在这种情况下，我需要将数据写入新工作簿，并在每次数据耗尽工作簿大小时继续执行此操作。我的问题： 1）如何知道工作簿何时耗尽 2）我应该如何创建一个新文件 3）在跟踪号码时我应该在哪里保存我的数据。 xls的。

谢谢！

Answer 1

如果输入数据超出工作簿的最大大小，则可以使用Big Grid Demo样式将数据写入工作簿。这将允许您将无限数据写入工作簿。

/** * * @param zipfile the template file * @param sheets the Map with
* key "name of the sheet entry to substitute
* (e.g. xl/worksheets/sheet1.xml, xl/worksheets/sheet2.xml etc)" * and value "XML file with the sheet data" * @param out the stream to write the result to */

private static void substitute(File zipfile, Map<String, File> sheets, OutputStream out) throws IOException {  
        ZipFile zip = new ZipFile(zipfile);  

        ZipOutputStream zos = new ZipOutputStream(out);  

        @SuppressWarnings("unchecked")  
        Enumeration<ZipEntry> en = (Enumeration<ZipEntry>) zip.entries();  
        while (en.hasMoreElements()) {  
            ZipEntry ze = en.nextElement();   
            if(!sheets.containsKey(ze.getName())){  
                zos.putNextEntry(new ZipEntry(ze.getName()));
                InputStream is = zip.getInputStream(ze);  
                copyStream(is, zos);  
                is.close();  
            }  
        }  

        for (Map.Entry<String, File> entry : sheets.entrySet()) {  
           // System.out.println("Key -->"+entry.getKey());  
            zos.putNextEntry(new ZipEntry(entry.getKey()));  
            InputStream is = new FileInputStream(entry.getValue());  
            copyStream(is, zos);  
            is.close();  
        }  
        zos.close();  
    }  

    private static void copyStream(InputStream in, OutputStream out) throws IOException {  
        byte[] chunk = new byte[1024];  
        int count;  
        while ((count = in.read(chunk)) >=0 ) {  
          out.write(chunk,0,count);  
        }  
    }  

    /** 
     * Writes spreadsheet data in a Writer. 
     * (YK: in future it may evolve in a full-featured API for streaming data in Excel) 
     */  
    public static class SpreadsheetWriter {  
        private final Writer _out;  
        private int _rownum;  

        public SpreadsheetWriter(Writer out){  
            _out = out;  
        }  

        public void beginSheet() throws IOException {  
            _out.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>" +  
                    "<worksheet xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\">" );  
            _out.write("<sheetData>\n");  
        }  

        public void endSheet() throws IOException {  
            _out.write("</sheetData>");  
            _out.write("</worksheet>");  
        }  

        /** 
         * Insert a new row 
         * 
         * @param rownum 0-based row number 
         */  
        public void insertRow(int rownum) throws IOException {  
            _out.write("<row r=\""+(rownum+1)+"\">\n");  
            this._rownum = rownum;  
        }  

        /** 
         * Insert row end marker 
         */  
        public void endRow() throws IOException {  
            _out.write("</row>\n");  
        }  

        public void createCell(int columnIndex, String value, int styleIndex) throws IOException {  
            String ref = new CellReference(_rownum, columnIndex).formatAsString();  
            _out.write("<c r=\""+ref+"\" t=\"inlineStr\"");  
            if(styleIndex != -1) _out.write(" s=\""+styleIndex+"\"");  
            _out.write(">");  
            _out.write("<is><t>"+value+"</t></is>");  
            _out.write("</c>");  
        }  

        public void createCell(int columnIndex, String value) throws IOException {  
            createCell(columnIndex, value, -1);  
        }  

        public void createCell(int columnIndex, double value, int styleIndex) throws IOException {  
            String ref = new CellReference(_rownum, columnIndex).formatAsString();  
            _out.write("<c r=\""+ref+"\" t=\"n\"");  
            if(styleIndex != -1) _out.write(" s=\""+styleIndex+"\"");  
            _out.write(">");  
            _out.write("<v>"+value+"</v>");  
            _out.write("</c>");  
        }  

        public void createCell(int columnIndex, double value) throws IOException {  
            createCell(columnIndex, value, -1);  
        }  

        public void createCell(int columnIndex, Calendar value, int styleIndex) throws IOException {  
            createCell(columnIndex, DateUtil.getExcelDate(value, false), styleIndex);  
        }  
    }

private static void substitute(File zipfile, Map<String, File> sheets, OutputStream out) throws IOException { ZipFile zip = new ZipFile(zipfile); ZipOutputStream zos = new ZipOutputStream(out); @SuppressWarnings("unchecked") Enumeration<ZipEntry> en = (Enumeration<ZipEntry>) zip.entries(); while (en.hasMoreElements()) { ZipEntry ze = en.nextElement(); if(!sheets.containsKey(ze.getName())){ zos.putNextEntry(new ZipEntry(ze.getName())); InputStream is = zip.getInputStream(ze); copyStream(is, zos); is.close(); } } for (Map.Entry<String, File> entry : sheets.entrySet()) { // System.out.println("Key -->"+entry.getKey()); zos.putNextEntry(new ZipEntry(entry.getKey())); InputStream is = new FileInputStream(entry.getValue()); copyStream(is, zos); is.close(); } zos.close(); } private static void copyStream(InputStream in, OutputStream out) throws IOException { byte[] chunk = new byte[1024]; int count; while ((count = in.read(chunk)) >=0 ) { out.write(chunk,0,count); } } /** * Writes spreadsheet data in a Writer. * (YK: in future it may evolve in a full-featured API for streaming data in Excel) */ public static class SpreadsheetWriter { private final Writer _out; private int _rownum; public SpreadsheetWriter(Writer out){ _out = out; } public void beginSheet() throws IOException { _out.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>" + "<worksheet xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\">" ); _out.write("<sheetData>\n"); } public void endSheet() throws IOException { _out.write("</sheetData>"); _out.write("</worksheet>"); } /** * Insert a new row * * @param rownum 0-based row number */ public void insertRow(int rownum) throws IOException { _out.write("<row r=\""+(rownum+1)+"\">\n"); this._rownum = rownum; } /** * Insert row end marker */ public void endRow() throws IOException { _out.write("</row>\n"); } public void createCell(int columnIndex, String value, int styleIndex) throws IOException { String ref = new CellReference(_rownum, columnIndex).formatAsString(); _out.write("<c r=\""+ref+"\" t=\"inlineStr\""); if(styleIndex != -1) _out.write(" s=\""+styleIndex+"\""); _out.write(">"); _out.write("<is><t>"+value+"</t></is>"); _out.write("</c>"); } public void createCell(int columnIndex, String value) throws IOException { createCell(columnIndex, value, -1); } public void createCell(int columnIndex, double value, int styleIndex) throws IOException { String ref = new CellReference(_rownum, columnIndex).formatAsString(); _out.write("<c r=\""+ref+"\" t=\"n\""); if(styleIndex != -1) _out.write(" s=\""+styleIndex+"\""); _out.write(">"); _out.write("<v>"+value+"</v>"); _out.write("</c>"); } public void createCell(int columnIndex, double value) throws IOException { createCell(columnIndex, value, -1); } public void createCell(int columnIndex, Calendar value, int styleIndex) throws IOException { createCell(columnIndex, DateUtil.getExcelDate(value, false), styleIndex); } }

您只需在将数据写入工作簿时调用substitute（）方法，