[转]POI大数据量Excel解决方案

全文转载自：jinshuaiwang的博客

目前处理Excel的开源javaAPI主要有两种，一是Jxl（Java Excel API）,Jxl只支持Excel2003以下的版本。另外一种是Apache的Jakarta POI,相比于Jxl,POI对微软办公文档的支持更加强大，但是它使用复杂，上手慢。POI可支持更高的Excel版本2007。对Excel的读取，POI有两种模式，一是用户模式，这种方式同Jxl的使用很类似，使用简单，都是将文件一次性读到内存，文件小的时候，没有什么问题，当文件大的时候，就会出现OutOfMemory的内存溢出问题。第二种是事件驱动模式，拿Excel2007来说，其内容采用XML的格式来存储，所以处理excel就是解析XML，而目前使用事件驱动模式解析XML的API是SAX(Simple API for XML)，这种模型在读取XML文档时，并没有将整个文档读入内存，而是按顺序将整个文档解析完，在解析过程中，会主动产生事件交给程序中相应的处理函数来处理当前内容。因此这种方式对系统资源要求不高，可以处理海量数据。笔者曾经做过测试，这种方法处理一千万条，每条五列的数据花费大约11分钟。可见处理海量数据的文件事件驱动是一个很好的方式。而本文中用到的AbstractExcel2003Reader、AbstractExcel2007Reader对Excel的读取都是采用这种POI的事件驱动模式。至于Excel的写操作，对较高版本的Excel2007，POI提供了很好的支持，主要流程是第一步构建工作薄和电子表格对象，第二步在一个流中构建文本文件，第三步使用流中产生的数据替换模板中的电子表格。这种方式也可以处理海量数据文件。AbstractExcel2007Writer就是使用这种方式进行写操作。对于写入较低版本的Excel2003，POI使用了用户模式来处理，就是将整个文档加载进内存，如果数据量大的话就会出现内存溢出的问题，Excel2003Writer就是使用这种方式。据笔者的测试，如果数据量大于3万条，每条8列的话，就会报OutOfMemory的错误。Excel2003中每个电子表格的记录数必须在65536以下，否则就会发生异常。目前还没有好的解决方案，建议对于海量数据写入操作，尽量使用Excel2007。

    /**
     * 抽象Excel2003读取器，通过实现HSSFListener监听器，采用事件驱动模式解析excel2003
     * 中的内容，遇到特定事件才会触发，大大减少了内存的使用。
     *
     */
    public  class Excel2003Reader implements HSSFListener{
        private int minColumns = -1;
        private POIFSFileSystem fs;
        private int lastRowNumber;
        private int lastColumnNumber;  

        /** Should we output the formula, or the value it has? */
        private boolean outputFormulaValues = true;  

        /** For parsing Formulas */
        private SheetRecordCollectingListener workbookBuildingListener;
        //excel2003工作薄
        private HSSFWorkbook stubWorkbook;  

        // Records we pick up as we process
        private SSTRecord sstRecord;
        private FormatTrackingHSSFListener formatListener;  

        //表索引
        private int sheetIndex = -1;
        private BoundSheetRecord[] orderedBSRs;
        @SuppressWarnings("unchecked")
        private ArrayList boundSheetRecords = new ArrayList();  

        // For handling formulas with string results
        private int nextRow;
        private int nextColumn;
        private boolean outputNextStringRecord;
        //当前行
        private int curRow = 0;
        //存储行记录的容器
        private List<String> rowlist = new ArrayList<String>();;
        @SuppressWarnings( "unused")
        private String sheetName;  

        private IRowReader rowReader;  

        public void setRowReader(IRowReader rowReader){
            this.rowReader = rowReader;
        }  

        /**
         * 遍历excel下所有的sheet
         * @throws IOException
         */
        public void process(String fileName) throws IOException {
            this.fs = new POIFSFileSystem(new FileInputStream(fileName));
            MissingRecordAwareHSSFListener listener = new MissingRecordAwareHSSFListener(
                    this);
            formatListener = new FormatTrackingHSSFListener(listener);
            HSSFEventFactory factory = new HSSFEventFactory();
            HSSFRequest request = new HSSFRequest();
            if (outputFormulaValues) {
                request.addListenerForAllRecords(formatListener);
            } else {
                workbookBuildingListener = new SheetRecordCollectingListener(
                        formatListener);
                request.addListenerForAllRecords(workbookBuildingListener);
            }
            factory.processWorkbookEvents(request, fs);
        }  

        /**
         * HSSFListener 监听方法，处理 Record
         */
        @SuppressWarnings("unchecked")
        public void processRecord(Record record) {
            int thisRow = -1;
            int thisColumn = -1;
            String thisStr = null;
            String value = null;
            switch (record.getSid()) {
                case BoundSheetRecord.sid:
                    boundSheetRecords.add(record);
                    break;
                case BOFRecord.sid:
                    BOFRecord br = (BOFRecord) record;
                    if (br.getType() == BOFRecord.TYPE_WORKSHEET) {
                        // 如果有需要，则建立子工作薄
                        if (workbookBuildingListener != null && stubWorkbook == null) {
                            stubWorkbook = workbookBuildingListener
                                    .getStubHSSFWorkbook();
                        }  

                        sheetIndex++;
                        if (orderedBSRs == null) {
                            orderedBSRs = BoundSheetRecord
                                    .orderByBofPosition(boundSheetRecords);
                        }
                        sheetName = orderedBSRs[sheetIndex].getSheetname();
                    }
                    break;  

                case SSTRecord.sid:
                    sstRecord = (SSTRecord) record;
                    break;  

                case BlankRecord.sid:
                    BlankRecord brec = (BlankRecord) record;
                    thisRow = brec.getRow();
                    thisColumn = brec.getColumn();
                    thisStr = "";
                    rowlist.add(thisColumn, thisStr);
                    break;
                case BoolErrRecord.sid: //单元格为布尔类型
                    BoolErrRecord berec = (BoolErrRecord) record;
                    thisRow = berec.getRow();
                    thisColumn = berec.getColumn();
                    thisStr = berec.getBooleanValue()+"";
                    rowlist.add(thisColumn, thisStr);
                    break;  

                case FormulaRecord.sid: //单元格为公式类型
                    FormulaRecord frec = (FormulaRecord) record;
                    thisRow = frec.getRow();
                    thisColumn = frec.getColumn();
                    if (outputFormulaValues) {
                        if (Double.isNaN(frec.getValue())) {
                            // Formula result is a string
                            // This is stored in the next record
                            outputNextStringRecord = true;
                            nextRow = frec.getRow();
                            nextColumn = frec.getColumn();
                        } else {
                            thisStr = formatListener.formatNumberDateCell(frec);
                        }
                    } else {
                        thisStr = '"' + HSSFFormulaParser.toFormulaString(stubWorkbook,
                                frec.getParsedExpression()) + '"';
                    }
                    rowlist.add(thisColumn,thisStr);
                    break;
                case StringRecord.sid://单元格中公式的字符串
                    if (outputNextStringRecord) {
                        // String for formula
                        StringRecord srec = (StringRecord) record;
                        thisStr = srec.getString();
                        thisRow = nextRow;
                        thisColumn = nextColumn;
                        outputNextStringRecord = false;
                    }
                    break;
                case LabelRecord.sid:
                    LabelRecord lrec = (LabelRecord) record;
                    curRow = thisRow = lrec.getRow();
                    thisColumn = lrec.getColumn();
                    value = lrec.getValue().trim();
                    value = value.equals("")?" ":value;
                    this.rowlist.add(thisColumn, value);
                    break;
                case LabelSSTRecord.sid:  //单元格为字符串类型
                    LabelSSTRecord lsrec = (LabelSSTRecord) record;
                    curRow = thisRow = lsrec.getRow();
                    thisColumn = lsrec.getColumn();
                    if (sstRecord == null) {
                        rowlist.add(thisColumn, " ");
                    } else {
                        value =  sstRecord
                        .getString(lsrec.getSSTIndex()).toString().trim();
                        value = value.equals("")?" ":value;
                        rowlist.add(thisColumn,value);
                    }
                    break;
                case NumberRecord.sid:  //单元格为数字类型
                    NumberRecord numrec = (NumberRecord) record;
                    curRow = thisRow = numrec.getRow();
                    thisColumn = numrec.getColumn();
                    value = formatListener.formatNumberDateCell(numrec).trim();
                    value = value.equals("")?" ":value;
                    // 向容器加入列值
                    rowlist.add(thisColumn, value);
                    break;
                default:
                    break;
            }  

            // 遇到新行的操作
            if (thisRow != -1 && thisRow != lastRowNumber) {
                lastColumnNumber = -1;
            }  

            // 空值的操作
            if (record instanceof MissingCellDummyRecord) {
                MissingCellDummyRecord mc = (MissingCellDummyRecord) record;
                curRow = thisRow = mc.getRow();
                thisColumn = mc.getColumn();
                rowlist.add(thisColumn," ");
            }  

            // 更新行和列的值
            if (thisRow > -1)
                lastRowNumber = thisRow;
            if (thisColumn > -1)
                lastColumnNumber = thisColumn;  

            // 行结束时的操作
            if (record instanceof LastCellOfRowDummyRecord) {
                if (minColumns > 0) {
                    // 列值重新置空
                    if (lastColumnNumber == -1) {
                        lastColumnNumber = 0;
                    }
                }
                lastColumnNumber = -1;
                    // 每行结束时， 调用getRows() 方法
                rowReader.getRows(sheetIndex,curRow, rowlist);  

                // 清空容器
                rowlist.clear();
            }
        }  

    }  

    /**
     * 抽象Excel2007读取器，excel2007的底层数据结构是xml文件，采用SAX的事件驱动的方法解析
     * xml，需要继承DefaultHandler，在遇到文件内容时，事件会触发，这种做法可以大大降低
     * 内存的耗费，特别使用于大数据量的文件。
     *
     */
    public class Excel2007Reader extends DefaultHandler {
        //共享字符串表
        private SharedStringsTable sst;
        //上一次的内容
        private String lastContents;
        private boolean nextIsString;  

        private int sheetIndex = -1;
        private List<String> rowlist = new ArrayList<String>();
        //当前行
        private int curRow = 0;
        //当前列
        private int curCol = 0;
        //日期标志
        private boolean dateFlag;
        //数字标志
        private boolean numberFlag;  

        private boolean isTElement;  

        private IRowReader rowReader;  

        public void setRowReader(IRowReader rowReader){
            this.rowReader = rowReader;
        }  

        /**只遍历一个电子表格，其中sheetId为要遍历的sheet索引，从1开始，1-3
         * @param filename
         * @param sheetId
         * @throws Exception
         */
        public void processOneSheet(String filename,int sheetId) throws Exception {
            OPCPackage pkg = OPCPackage.open(filename);
            XSSFReader r = new XSSFReader(pkg);
            SharedStringsTable sst = r.getSharedStringsTable();
            XMLReader parser = fetchSheetParser(sst);  

            // 根据 rId# 或 rSheet# 查找sheet
            InputStream sheet2 = r.getSheet("rId"+sheetId);
            sheetIndex++;
            InputSource sheetSource = new InputSource(sheet2);
            parser.parse(sheetSource);
            sheet2.close();
        }  

        /**
         * 遍历工作簿中所有的电子表格
         * @param filename
         * @throws Exception
         */
        public void process(String filename) throws Exception {
            OPCPackage pkg = OPCPackage.open(filename);
            XSSFReader r = new XSSFReader(pkg);
            SharedStringsTable sst = r.getSharedStringsTable();
            XMLReader parser = fetchSheetParser(sst);
            Iterator<InputStream> sheets = r.getSheetsData();
            while (sheets.hasNext()) {
                curRow = 0;
                sheetIndex++;
                InputStream sheet = sheets.next();
                InputSource sheetSource = new InputSource(sheet);
                parser.parse(sheetSource);
                sheet.close();
            }
        }  

        public XMLReader fetchSheetParser(SharedStringsTable sst)
                throws SAXException {
            XMLReader parser = XMLReaderFactory
                    .createXMLReader("org.apache.xerces.parsers.SAXParser");
            this.sst = sst;
            parser.setContentHandler(this);
            return parser;
        }  

        public void startElement(String uri, String localName, String name,
                Attributes attributes) throws SAXException {  

            // c => 单元格
            if ("c".equals(name)) {
                // 如果下一个元素是 SST 的索引，则将nextIsString标记为true
                String cellType = attributes.getValue("t");
                if ("s".equals(cellType)) {
                    nextIsString = true;
                } else {
                    nextIsString = false;
                }
                //日期格式
                String cellDateType = attributes.getValue("s");
                if ("1".equals(cellDateType)){
                    dateFlag = true;
                } else {
                    dateFlag = false;
                }
                String cellNumberType = attributes.getValue("s");
                if("2".equals(cellNumberType)){
                    numberFlag = true;
                } else {
                    numberFlag = false;
                }  

            }
            //当元素为t时
            if("t".equals(name)){
                isTElement = true;
            } else {
                isTElement = false;
            }  

            // 置空
            lastContents = "";
        }  

        public void endElement(String uri, String localName, String name)
                throws SAXException {  

            // 根据SST的索引值的到单元格的真正要存储的字符串
            // 这时characters()方法可能会被调用多次
            if (nextIsString) {
                try {
                    int idx = Integer.parseInt(lastContents);
                    lastContents = new XSSFRichTextString(sst.getEntryAt(idx))
                            .toString();
                } catch (Exception e) {  

                }
            }
            //t元素也包含字符串
            if(isTElement){
                String value = lastContents.trim();
                rowlist.add(curCol, value);
                curCol++;
                isTElement = false;
                // v => 单元格的值，如果单元格是字符串则v标签的值为该字符串在SST中的索引
                // 将单元格内容加入rowlist中，在这之前先去掉字符串前后的空白符
            } else if ("v".equals(name)) {
                String value = lastContents.trim();
                value = value.equals("")?" ":value;
                //日期格式处理
                if(dateFlag){
                     Date date = HSSFDateUtil.getJavaDate(Double.valueOf(value));
                     SimpleDateFormat dateFormat = new SimpleDateFormat(
                     "dd/MM/yyyy");
                     value = dateFormat.format(date);
                }
                //数字类型处理
                if(numberFlag){
                    BigDecimal bd = new BigDecimal(value);
                    value = bd.setScale(3,BigDecimal.ROUND_UP).toString();
                }
                rowlist.add(curCol, value);
                curCol++;
            }else {
                //如果标签名称为 row ，这说明已到行尾，调用 optRows() 方法
                if (name.equals("row")) {
                    rowReader.getRows(sheetIndex,curRow,rowlist);
                    rowlist.clear();
                    curRow++;
                    curCol = 0;
                }
            }  

        }  

        public void characters(char[] ch, int start, int length)
                throws SAXException {
            //得到单元格内容的值
            lastContents += new String(ch, start, length);
        }
    }  

    public class ExcelReaderUtil {  

        //excel2003扩展名
        public static final String EXCEL03_EXTENSION = ".xls";
        //excel2007扩展名
        public static final String EXCEL07_EXTENSION = ".xlsx";  

        /**
         * 读取Excel文件，可能是03也可能是07版本
         * @param excel03
         * @param excel07
         * @param fileName
         * @throws Exception
         */
        public static void readExcel(IRowReader reader,String fileName) throws Exception{
            // 处理excel2003文件
            if (fileName.endsWith(EXCEL03_EXTENSION)){
                Excel2003Reader excel03 = new Excel2003Reader();
                excel03.setRowReader(reader);
                excel03.process(fileName);
            // 处理excel2007文件
            } else if (fileName.endsWith(EXCEL07_EXTENSION)){
                Excel2007Reader excel07 = new Excel2007Reader();
                excel07.setRowReader(reader);
                excel07.process(fileName);
            } else {
                throw new  Exception("文件格式错误，fileName的扩展名只能是xls或xlsx。");
            }
        }
    }  

    public interface IRowReader {  

        /**业务逻辑实现方法
         * @param sheetIndex
         * @param curRow
         * @param rowlist
         */
        public  void getRows(int sheetIndex,int curRow, List<String> rowlist);
    }  

    public class RowReader implements IRowReader{  

        /* 业务逻辑实现方法
         * @see com.eprosun.util.excel.IRowReader#getRows(int, int, java.util.List)
         */
        public void getRows(int sheetIndex, int curRow, List<String> rowlist) {
            // TODO Auto-generated method stub
            System.out.print(curRow+" ");
            for (int i = 0; i < rowlist.size(); i++) {
                System.out.print(rowlist.get(i) + " ");
            }
            System.out.println();
        }  

    }  

    public class Main {  

        public static void main(String[] args) throws Exception {
            IRowReader reader = new RowReader();
            //ExcelReaderUtil.readExcel(reader, "F://te03.xls");
            ExcelReaderUtil.readExcel(reader, "F://test07.xlsx");
        }
    }  

    public class Excel2003Writer {  

        /**
         * @param args
         */
        public static void main(String[] args) {
            try{
                System.out.println("开始写入excel2003....");
                writeExcel("tes2003.xls");
                System.out.println("写完xcel2003");
            } catch (IOException e) {  

            }
        }  

        /**
         * 写入excel并填充内容,一个sheet只能写65536行以下，超出会报异常，写入时建议使用AbstractExcel2007Writer
         * @param fileName
         * @throws IOException
         */
        public static void writeExcel(String fileName) throws IOException{  

                // 创建excel2003对象
                Workbook wb = new HSSFWorkbook();  

                // 设置文件放置路径和文件名
                FileOutputStream fileOut = new FileOutputStream(fileName);
                // 创建新的表单
                Sheet sheet = wb.createSheet("newsheet");
                // 创建新行
                for(int i=0;i<20000;i++){
                    Row row = sheet.createRow(i);
                    // 创建单元格
                    Cell cell = row.createCell(0);
                    // 设置单元格值
                    cell.setCellValue(1);
                    row.createCell(1).setCellValue(1+i);
                    row.createCell(2).setCellValue(true);
                    row.createCell(3).setCellValue(0.43d);
                    row.createCell(4).setCellValue('d');
                    row.createCell(5).setCellValue("");
                    row.createCell(6).setCellValue("第七列"+i);
                    row.createCell(7).setCellValue("第八列"+i);
                }
                wb.write(fileOut);
                fileOut.close();
        }  

    }  

    /**
     * 抽象excel2007读入器，先构建.xlsx一张模板，改写模板中的sheet.xml,使用这种方法
     * 写入.xlsx文件，不需要太大的内存
     *
     */
    public abstract class AbstractExcel2007Writer {  

        private SpreadsheetWriter sw;  

        /**
         * 写入电子表格的主要流程
         * @param fileName
         * @throws Exception
         */
        public void process(String fileName) throws Exception{
            // 建立工作簿和电子表格对象
            XSSFWorkbook wb = new XSSFWorkbook();
            XSSFSheet sheet = wb.createSheet("sheet1");
            // 持有电子表格数据的xml文件名 例如 /xl/worksheets/sheet1.xml
            String sheetRef = sheet.getPackagePart().getPartName().getName();  

            // 保存模板
            FileOutputStream os = new FileOutputStream("template.xlsx");
            wb.write(os);
            os.close();  

            // 生成xml文件
            File tmp = File.createTempFile("sheet", ".xml");
            Writer fw = new FileWriter(tmp);
            sw = new SpreadsheetWriter(fw);
            generate();
            fw.close();  

            // 使用产生的数据替换模板
            File templateFile = new File("template.xlsx");
            FileOutputStream out = new FileOutputStream(fileName);
            substitute(templateFile, tmp, sheetRef.substring(1), out);
            out.close();
            //删除文件之前调用一下垃圾回收器，否则无法删除模板文件
            System.gc();
            // 删除临时模板文件
            if (templateFile.isFile()&&templateFile.exists()){
                templateFile.delete();
            }
        }  

        /**
         * 类使用者应该使用此方法进行写操作
         * @throws Exception
         */
        public abstract void generate() throws Exception;  

        public void beginSheet() throws IOException {
            sw.beginSheet();
        }  

        public void insertRow(int rowNum) throws IOException {
            sw.insertRow(rowNum);
        }  

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

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

        public void endRow() throws IOException {
            sw.endRow();
        }  

        public void endSheet() throws IOException {
            sw.endSheet();
        }  

        /**
         *
         * @param zipfile the template file
         * @param tmpfile the XML file with the sheet data
         * @param entry the name of the sheet entry to substitute, e.g. xl/worksheets/sheet1.xml
         * @param out the stream to write the result to
         */
        private static void substitute(File zipfile, File tmpfile, String entry,
                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 (!ze.getName().equals(entry)) {
                    zos.putNextEntry(new ZipEntry(ze.getName()));
                    InputStream is = zip.getInputStream(ze);
                    copyStream(is, zos);
                    is.close();
                }
            }
            zos.putNextEntry(new ZipEntry(entry));
            InputStream is = new FileInputStream(tmpfile);
            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);
            }
        }  

        /**
         * 在写入器中写入电子表格
         *
         */
        public static class SpreadsheetWriter {
            private final Writer _out;
            private int _rownum;
            private static String LINE_SEPARATOR = System.getProperty("line.separator");  

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

            public void beginSheet() throws IOException {
                _out.write("<?xml version=\"1.0\" encoding=\"GB2312\"?>"
                                + "<worksheet xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\">");
                _out.write("<sheetData>"+LINE_SEPARATOR);
            }  

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

            /**
             * 插入新行
             *
             * @param rownum 以0开始
             */
            public void insertRow(int rownum) throws IOException {
                _out.write("<row r=\"" + (rownum + 1) + "\">"+LINE_SEPARATOR);
                this._rownum = rownum;
            }  

            /**
             * 插入行结束标志
             */
            public void endRow() throws IOException {
                _out.write("</row>"+LINE_SEPARATOR);
            }  

            /**
             * 插入新列
             * @param columnIndex
             * @param value
             * @param styleIndex
             * @throws IOException
             */
            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>"+XMLEncoder.encode(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);
            }
        }
    }  

    public class Excel2007WriterImpl extends AbstractExcel2007Writer{  

        /**
         * @param args
         * @throws Exception
         */
        public static void main(String[] args) throws Exception {
            // TODO Auto-generated method stub
            System.out.println("............................");
            long start = System.currentTimeMillis();
            //构建excel2007写入器
            AbstractExcel2007Writer excel07Writer = new Excel2007WriterImpl();
            //调用处理方法
            excel07Writer.process("F://test07.xlsx");
            long end = System.currentTimeMillis();
            System.out.println("....................."+(end-start)/1000);
        }  

        /*
         * 可根据需求重写此方法，对于单元格的小数或者日期格式，会出现精度问题或者日期格式转化问题，建议使用字符串插入方法
         * @see com.excel.ver2.AbstractExcel2007Writer#generate()
         */
        @Override
        public void generate()throws Exception {
            //电子表格开始
            beginSheet();
            for (int rownum = 0; rownum < 100; rownum++) {
                //插入新行
                insertRow(rownum);
                //建立新单元格,索引值从0开始,表示第一列
                createCell(0, "中国<" + rownum + "!");
                createCell(1, 34343.123456789);
                createCell(2, "23.67%");
                createCell(3, "12:12:23");
                createCell(4, "2010-10-11 12:12:23");
                createCell(5, "true");
                createCell(6, "false");  

                //结束行
                endRow();
            }
            //电子表格结束
            endSheet();
        }  

    }  

    public class XMLEncoder {  

        private static final String[] xmlCode = new String[256];  

        static {
            // Special characters
            xmlCode['\''] = "'";
            xmlCode['\"'] = """; // double quote
            xmlCode['&'] = "&"; // ampersand
            xmlCode['<'] = "<"; // lower than
            xmlCode['>'] = ">"; // greater than
        }  

        /**
         * <p>
         * Encode the given text into xml.
         * </p>
         *
         * @param string the text to encode
         * @return the encoded string
         */
        public static String encode(String string) {
            if (string == null) return "";
            int n = string.length();
            char character;
            String xmlchar;
            StringBuffer buffer = new StringBuffer();
            // loop over all the characters of the String.
            for (int i = 0; i < n; i++) {
                character = string.charAt(i);
                // the xmlcode of these characters are added to a StringBuffer one by one
                try {
                    xmlchar = xmlCode[character];
                    if (xmlchar == null) {
                        buffer.append(character);
                    } else {
                        buffer.append(xmlCode[character]);
                    }
                } catch (ArrayIndexOutOfBoundsException aioobe) {
                    buffer.append(character);
                }
            }
            return buffer.toString();
        }  

    }