使用apache poi怎么实现导出excel文件

使用apache poi怎么实现导出excel文件？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。

代码如下：

package com.icourt.util;import org.apache.commons.collections4.CollectionUtils;import org.apache.poi.openxml4j.exceptions.InvalidFORMatException;import org.apache.poi.ss.usermodel.*;import org.apache.poi.ss.util.CellRangeAddress;import java.io.*;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import java.util.Map.Entry;import java.util.regex.Matcher;import java.util.regex.Pattern;public class ExcelExportUtil {  //模板map  private Map<String, Workbook> tempWorkbook = new HashMap<String, Workbook>();  //模板输入流map  private Map<String, InputStream> tempStream = new HashMap<String, InputStream>();    public void writeData(String templateFilePath, Map<String, Object> dataMap, int sheetNo) throws IOException, InvalidFormatException {    if (dataMap == null || dataMap.isEmpty()) {      return;    }    //读取模板    Workbook wbModule = getTempWorkbook(templateFilePath);    //数据填充的sheet    Sheet wsheet = wbModule.getSheetAt(sheetNo);    for (Entry<String, Object> entry : dataMap.entrySet()) {      String point = entry.geTKEy();      Object data = entry.getValue();      TempCell cell = getCell(point, data, wsheet);      //指定坐标赋值      setCell(cell, wsheet);    }    //设置生成excel中公式自动计算    wsheet.setForceFormulaRecalculation(true);  }    public void writeDateList(String templateFilePath, String[] heads, List<Map<Integer, Object>> datalist, int sheetNo) throws IOException, InvalidFormatException {    if (heads == null || heads.length <= 0 || CollectionUtils.isEmpty(datalist)) {      return;    }    //读取模板    Workbook wbModule = getTempWorkbook(templateFilePath);    //数据填充的sheet    Sheet wsheet = wbModule.getSheetAt(sheetNo);    //列表数据模板cell    List<TempCell> tempCells = new ArrayList<TempCell>(heads.length);    for (String point : heads) {      TempCell tempCell = getCell(point, null, wsheet);      //取得合并单元格位置 -1:表示不是合并单元格      int pos = isMergedRegion(wsheet, tempCell.getRow(), tempCell.getColumn());      if (pos > -1) {        CellRangeAddress range = wsheet.getMergedRegion(pos);        tempCell.setColumnSize(range.getLastColumn() - range.getFirstColumn());      }      tempCells.add(tempCell);    }    //赋值    for (int i = 0; i < datalist.size(); i++) {//数据行      Map<Integer, Object> dataMap = datalist.get(i);      for (int j = 0; j < tempCells.size(); j++) {//列        TempCell tempCell = tempCells.get(j);        tempCell.setData(dataMap.get(j + 1));        setCell(tempCell, wsheet);        tempCell.setRow(tempCell.getRow() + 1);      }    }  }    private Workbook getTempWorkbook(String templateFilePath) throws IOException, InvalidFormatException {    if (!tempWorkbook.containsKey(templateFilePath)) {      InputStream inputStream = getInputStream(templateFilePath);      tempWorkbook.put(templateFilePath, WorkbookFactory.create(inputStream));    }    return tempWorkbook.get(templateFilePath);  }    private InputStream getInputStream(String templateFilePath) throws FileNotFoundException {    if (!tempStream.containsKey(templateFilePath)) {      tempStream.put(templateFilePath, new FileInputStream((templateFilePath)));    }    return tempStream.get(templateFilePath);  }    private TempCell getCell(String point, Object data, Sheet sheet) {    TempCell tempCell = new TempCell();    //得到列  字母    String lineStr = "";    String reg = "[A-Z]+";    Pattern p = Pattern.compile(reg);    Matcher m = p.matcher(point);    while (m.find()) {      lineStr = m.group();    }    //将列字母转成列号 根据ascii转换    char[] ch = lineStr.toCharArray();    int column = 0;    for (int i = 0; i < ch.length; i++) {      char c = ch[i];      int post = ch.length - i - 1;      int r = (int) Math.pow(10, post);      column = column + r * ((int) c - 65);    }    tempCell.setColumn(column);    //得到行号    reg = "[1-9]+";    p = Pattern.compile(reg);    m = p.matcher(point);    while (m.find()) {      tempCell.setRow((Integer.parseInt(m.group()) - 1));    }    //获取模板指定单元格样式,设置到tempCell(写列表数据的时候用)    Row rowIn = sheet.getRow(tempCell.getRow());    if (rowIn == null) {      rowIn = sheet.createRow(tempCell.getRow());    }    Cell cellIn = rowIn.getCell(tempCell.getColumn());    if (cellIn == null) {      cellIn = rowIn.createCell(tempCell.getColumn());    }    tempCell.setCellStyle(cellIn.getCellStyle());    tempCell.setData(data);    return tempCell;  }    private void setCell(TempCell tempCell, Sheet sheet) {    if (tempCell.getColumnSize() > -1) {      CellRangeAddress rangeAddress = mergeRegion(sheet, tempCell.getRow(), tempCell.getRow(), tempCell.getColumn(), tempCell.getColumn() + tempCell.getColumnSize());      setRegionStyle(tempCell.getCellStyle(), rangeAddress, sheet);    }    Row rowIn = sheet.getRow(tempCell.getRow());    if (rowIn == null) {      copyRows(tempCell.getRow() - 1, tempCell.getRow() - 1, tempCell.getRow(), sheet);//复制上一行      rowIn = sheet.getRow(tempCell.getRow());    }    Cell cellIn = rowIn.getCell(tempCell.getColumn());    if (cellIn == null) {      cellIn = rowIn.createCell(tempCell.getColumn());    }    //根据data类型给cell赋值    if (tempCell.getData() instanceof String) {      cellIn.setCellValue((String) tempCell.getData());    } else if (tempCell.getData() instanceof Integer) {      cellIn.setCellValue((int) tempCell.getData());    } else if (tempCell.getData() instanceof Double) {      cellIn.setCellValue((double) tempCell.getData());    } else {      cellIn.setCellValue((String) tempCell.getData());    }    //样式    if (tempCell.getCellStyle() != null && tempCell.getColumnSize() == -1) {      cellIn.setCellStyle(tempCell.getCellStyle());    }  }    public void writeAndClose(String templateFilePath, OutputStream os) throws IOException, InvalidFormatException {    if (getTempWorkbook(templateFilePath) != null) {      getTempWorkbook(templateFilePath).write(os);      tempWorkbook.remove(templateFilePath);    }    if (getInputStream(templateFilePath) != null) {      getInputStream(templateFilePath).close();      tempStream.remove(templateFilePath);    }  }    private Integer isMergedRegion(Sheet sheet, int row, int column) {    for (int i = 0; i < sheet.getNumMergedRegions(); i++) {      CellRangeAddress range = sheet.getMergedRegion(i);      int firstColumn = range.getFirstColumn();      int lastColumn = range.getLastColumn();      int firstRow = range.getFirstRow();      int lastRow = range.getLastRow();      if (row >= firstRow && row <= lastRow) {        if (column >= firstColumn && column <= lastColumn) {          return i;        }      }    }    return -1;  }    private CellRangeAddress mergeRegion(Sheet sheet, int firstRow, int lastRow, int firstCol, int lastCol) {    CellRangeAddress rang = new CellRangeAddress(firstRow, lastRow, firstCol, lastCol);    sheet.addMergedRegion(rang);    return rang;  }    private void setRegionStyle(CellStyle cs, CellRangeAddress region, Sheet sheet) {    for (int i = region.getFirstRow(); i <= region.getLastRow(); i++) {      Row row = sheet.getRow(i);      if (row == null) row = sheet.createRow(i);      for (int j = region.getFirstColumn(); j <= region.getLastColumn(); j++) {        Cell cell = row.getCell(j);        if (cell == null) {          cell = row.createCell(j);          cell.setCellValue("");        }        cell.setCellStyle(cs);      }    }  }    private void copyRows(int startRow, int endRow, int pPosition, Sheet sheet) {    int pStartRow = startRow - 1;    int pEndRow = endRow - 1;    int targetRowFrom;    int targetRowTo;    int columnCount;    CellRangeAddress region = null;    int i;    int j;    if (pStartRow == -1 || pEndRow == -1) {      return;    }    // 拷贝合并的单元格    for (i = 0; i < sheet.getNumMergedRegions(); i++) {      region = sheet.getMergedRegion(i);      if ((region.getFirstRow() >= pStartRow)          && (region.getLastRow() <= pEndRow)) {        targetRowFrom = region.getFirstRow() - pStartRow + pPosition;        targetRowTo = region.getLastRow() - pStartRow + pPosition;        CellRangeAddress newRegion = region.copy();        newRegion.setFirstRow(targetRowFrom);        newRegion.setFirstColumn(region.getFirstColumn());        newRegion.setLastRow(targetRowTo);        newRegion.setLastColumn(region.getLastColumn());        sheet.addMergedRegion(newRegion);      }    }    // 设置列宽    for (i = pStartRow; i <= pEndRow; i++) {      Row sourceRow = sheet.getRow(i);      columnCount = sourceRow.getLastCellNum();      if (sourceRow != null) {        Row newRow = sheet.createRow(pPosition - pStartRow + i);        newRow.setHeight(sourceRow.getHeight());        for (j = 0; j < columnCount; j++) {          Cell templateCell = sourceRow.getCell(j);          if (templateCell != null) {            Cell newCell = newRow.createCell(j);            copyCell(templateCell, newCell);          }        }      }    }  }    private void copyCell(Cell srcCell, Cell distCell) {    distCell.setCellStyle(srcCell.getCellStyle());    if (srcCell.getCellComment() != null) {      distCell.setCellComment(srcCell.getCellComment());    }    int srcCellType = srcCell.getCellType();    distCell.setCellType(srcCellType);  }    class TempCell {    private int row;    private int column;    private CellStyle cellStyle;    private Object data;    //用于列表合并,表示几列合并    private int columnSize = -1;    public int getColumn() {      return column;    }    public void setColumn(int column) {      this.column = column;    }    public int getRow() {      return row;    }    public void setRow(int row) {      this.row = row;    }    public CellStyle getCellStyle() {      return cellStyle;    }    public void setCellStyle(CellStyle cellStyle) {      this.cellStyle = cellStyle;    }    public Object getData() {      return data;    }    public void setData(Object data) {      this.data = data;    }    public int getColumnSize() {      return columnSize;    }    public void setColumnSize(int columnSize) {      this.columnSize = columnSize;    }  }  public static void main(String[] args) throws FileNotFoundException, IOException, InvalidFormatException {    String templateFilePath = ExcelExportUtil.class.getClassLoader().getResource("plugin/ProTiming.xlsx").getPath();    File file = new File("/Users/sql/Downloads/test/data.xlsx");    OutputStream os = new FileOutputStream(file);    ExcelExportUtil excel = new ExcelExportUtil();    Map<String, Object> dataMap = new HashMap<String, Object>();    dataMap.put("B1", "03_Alpha_项目工作时间统计表");    dataMap.put("B2", "统计时间：2017/01/01 - 2017/03/31");    excel.writeData(templateFilePath, dataMap, 0);    List<Map<Integer, Object>> datalist = new ArrayList<Map<Integer, Object>>();    Map<Integer, Object> data = new HashMap<Integer, Object>();    data.put(1, "3/10/17");    data.put(2, "18:50");    data.put(3, "19:00");    data.put(4, "李子鹏");    data.put(5, "新增项目键值对接口,供任务计时调用");    data.put(6, "代码开发");    data.put(7, "3.17");    datalist.add(data);    data = new HashMap<Integer, Object>();    data.put(1, "3/10/17");    data.put(2, "18:50");    data.put(3, "19:00");    data.put(4, "李子鹏");    data.put(5, "新增项目键值对接口,供任务计时调用");    data.put(6, "代码开发");    data.put(7, "3.17");    datalist.add(data);    data = new HashMap<Integer, Object>();    data.put(1, "3/10/17");    data.put(2, "18:50");    data.put(3, "19:00");    data.put(4, "李子鹏");    data.put(5, "新增项目键值对接口,供任务计时调用");    data.put(6, "代码开发");    data.put(7, "3.17");    datalist.add(data);    data = new HashMap<Integer, Object>();    data.put(1, "3/10/17");    data.put(2, "18:50");    data.put(3, "19:00");    data.put(4, "李子鹏");    data.put(5, "新增项目键值对接口,供任务计时调用");    data.put(6, "代码开发");    data.put(7, "3.17");    datalist.add(data);    data = new HashMap<Integer, Object>();    data.put(1, "3/10/17");    data.put(2, "18:50");    data.put(3, "19:00");    data.put(4, "李子鹏");    data.put(5, "新增项目键值对接口,供任务计时调用");    data.put(6, "代码开发");    data.put(7, "3.17");    datalist.add(data);    data = new HashMap<Integer, Object>();    data.put(1, "3/10/17");    data.put(2, "18:50");    data.put(3, "19:00");    data.put(4, "李子鹏");    data.put(5, "新增项目键值对接口,供任务计时调用");    data.put(6, "代码开发");    data.put(7, "3.17");    datalist.add(data);    data = new HashMap<Integer, Object>();    data.put(1, "3/10/17");    data.put(2, "18:50");    data.put(3, "19:00");    data.put(4, "李子鹏");    data.put(5, "新增项目键值对接口,供任务计时调用");    data.put(6, "代码开发");    data.put(7, "3.17");    datalist.add(data);    data = new HashMap<Integer, Object>();    data.put(1, "3/10/17");    data.put(2, "18:50");    data.put(3, "19:00");    data.put(4, "李子鹏");    data.put(5, "新增项目键值对接口,供任务计时调用");    data.put(6, "代码开发");    data.put(7, "3.17");    datalist.add(data);    data = new HashMap<Integer, Object>();    data.put(1, "3/10/17");    data.put(2, "18:50");    data.put(3, "19:00");    data.put(4, "李子鹏");    data.put(5, "新增项目键值对接口,供任务计时调用新增项目键值对接口,供任务计时调用新增项目键值对接口,供任务计时调用新增项目键值对接口,供任务计时调用新增项目键值对接口,供任务计时调用新增项目键值对接口,供任务计时调用新增项目键值对接口,供任务计时调用新增项目键值对接口,供任务计时调用");    data.put(6, "代码开发");    data.put(7, "3.17");    datalist.add(data);    data = new HashMap<Integer, Object>();    data.put(1, "");    data.put(2, "");    data.put(3, "");    data.put(4, "");    data.put(5, "");    data.put(6, "");    data.put(7, "");    datalist.add(data);    String[] heads = new String[]{"B4", "C4", "D4", "E4", "F4", "G4", "H4"};    excel.writeDateList(templateFilePath, heads, datalist, 0);    //写到输出流并移除资源    excel.writeAndClose(templateFilePath, os);    os.flush();    os.close();  }}