poi导出excel，表头数据动态拼装

/*
* 第一步：拼装表头和数据
*/
// 放多个sheet的集合
List<Map<String,Object>> datas = new ArrayList<Map<String,Object>>();
//字典项
String typeCode = Tool.getTypeCodeByCategory(belongsCategory);
List<DataDictVO> dataDicts = dataDictService.getDataDictListByTypeCode(typeCode);
List<Map<String,String>> purchaseMethodData = (List<Map<String,String>>) getDataInfoBusiness.getDataSourceList2(params, "TradeGetInfo", "category", belongsCategory, statisticalTime);
//动态表头
List<List<CellInfo>> headerTwo = new LinkedList<List<CellInfo>>();
List<CellInfo> firstTwo = new LinkedList<CellInfo>();
firstTwo.add(new CellInfo("来源系统",2,1));
if(!CollectionUtils.isEmpty(dataDicts)){
    for(DataDictVO dict:dataDicts){
        firstTwo.add(new CellInfo(dict.getName(),1,1));
    }
}
headerTwo.add(firstTwo);
List<CellInfo> second = new LinkedList<CellInfo>();
int colNum = 1;
second.add(new CellInfo("来源系统"));
if(!CollectionUtils.isEmpty(dataDicts)){
    for(int i=0;i<dataDicts.size();i++){
        second.add(new CellInfo("入库"));
        colNum += 1;
    }
}
headerTwo.add(second);
//表数据 
List<List<CellInfo>> dataTwo = new LinkedList<List<CellInfo>>();

for(Map<String,String> typeData:purchaseMethodData){
    List<CellInfo> row = new LinkedList<CellInfo>();
    row.add(new CellInfo(typeData.get("DATA_SOURCE_CODE_NAME")));
    for(DataDictVO dict:dataDicts){
        String code = dict.getCode() + "_ACCESS_NUM";
        row.add(new CellInfo(typeData.get(code)));
    }
    dataTwo.add(row);
}

Map<String, Object> mapTwo = new HashMap<String, Object>();
mapTwo.put("sheetName", "按类别统计");
mapTwo.put("title", "按类别统计");
mapTwo.put("unitInfo", "");
mapTwo.put("headerLength", colNum);
mapTwo.put("header", headerTwo);
mapTwo.put("data", dataTwo);
datas.add(mapTwo);
/*
* 第二步：调用工具类
*/
 /**
     * 导出成Excel表格
     * @param sheetName sheet名称  该类多Sheet
     * @param title    表格的title。eg:政府采购
     * @param unitInfo    表格单位信息。eg:金额单位:万元
     * @param headerLength    表头的最大列数（按未合并前的单元格算）
     * @param header 表头信息（见CellInfo）如果跨行则被合并的行不再需要说明跨行信息  即：跨行信息放在第一行出现该信息的CellInfo里。后面的每行只需要输入相同的内容即可。
     * @param data    同表头
     * @param out 输出流 将生成的Excel数据流传输到该输出流
     * @throws IOException
     */
    @SuppressWarnings("unchecked")
    public static HSSFWorkbook exportExcel(List<Map<String,Object>> datas) throws IOException{
        //创建工作簿
        HSSFWorkbook workbook = new HSSFWorkbook(); 
        //表头的样式
        HSSFCellStyle titlestyle = workbook.createCellStyle();// 创建样式对象 
        titlestyle.setAlignment(HSSFCellStyle.ALIGN_CENTER_SELECTION);// 水平居中 
        titlestyle.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 垂直居中 
        titlestyle.setBorderBottom(HSSFCellStyle.BORDER_THIN);   
        titlestyle.setBorderLeft(HSSFCellStyle.BORDER_THIN);   
        titlestyle.setBorderRight(HSSFCellStyle.BORDER_THIN);   
        titlestyle.setBorderTop(HSSFCellStyle.BORDER_THIN); 
//        titlestyle.setFillForegroundColor(HSSFColor.GREY_25_PERCENT.index);
//        titlestyle.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);    
        //字体 
        HSSFFont titleFont = workbook.createFont(); // 创建字体对象 
        titleFont.setFontHeightInPoints((short) 11); // 设置字体大小 
        titleFont.setFontName("微软雅黑"); // 设置为黑体字 
//        titleFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);//粗体
        titlestyle.setFont(titleFont); 
        //指定当单元格内容显示不下时自动换行 
        titlestyle.setWrapText(true);    
        //表数据的样式
        HSSFCellStyle style = workbook.createCellStyle();// 创建样式对象 
        style.setAlignment(HSSFCellStyle.ALIGN_CENTER_SELECTION);// 水平居中 
        style.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 垂直居中 
        style.setBorderBottom(HSSFCellStyle.BORDER_THIN);   
        style.setBorderLeft(HSSFCellStyle.BORDER_THIN);   
        style.setBorderRight(HSSFCellStyle.BORDER_THIN);   
        style.setBorderTop(HSSFCellStyle.BORDER_THIN); 
        //字体 
        HSSFFont font = workbook.createFont(); // 创建字体对象 
        font.setFontHeightInPoints((short) 11); // 设置字体大小 
        font.setFontName("微软雅黑"); // 设置为黑体字 
        style.setFont(font); 
        //指定当单元格内容显示不下时自动换行 
        style.setWrapText(true);   
        for(Map<String,Object> map:datas){
            String sheetName = map.get("sheetName").toString();
            String title = map.get("title").toString();
            String unitInfo = map.get("unitInfo").toString();
            int headerLength  = (int)map.get("headerLength");
            List<List<CellInfo>> header  = (List<List<CellInfo>>)map.get("header");
            List<List<CellInfo>> data  = (List<List<CellInfo>>)map.get("data");
            //创建Sheet
            HSSFSheet sheet = workbook.createSheet(sheetName);   
            //设置表格默认列宽度为20个字节
            sheet.setDefaultColumnWidth(20);  
            //设置第一行  （单位信息，定制）
            int rowNum = 0;
            if(null!=unitInfo){
                sheet.addMergedRegion(new CellRangeAddress(rowNum,1,0,headerLength-1));
                HSSFRow rowUnit = sheet.createRow(rowNum);   
                HSSFCell cellUnit = rowUnit.createCell(0);
                HSSFCellStyle unitStyle = workbook.createCellStyle();// 创建样式对象 
                unitStyle.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 垂直居中 
                unitStyle.setAlignment(HSSFCellStyle.ALIGN_RIGHT);
                unitStyle.setFont(font);
                cellUnit.setCellStyle(unitStyle); 
                cellUnit.setCellValue(unitInfo);
                rowNum =1;
            }
            //标题
            if(null!=title){
                rowNum++;
                HSSFRow rowHeader = sheet.createRow(rowNum);
                for(int i=0;i<headerLength;i++){
                    HSSFCell cellHeader = rowHeader.createCell(i);
                    cellHeader.setCellStyle(titlestyle); 
                    cellHeader.setCellValue(title);
                }
                rowNum++;
                HSSFRow title2 = sheet.createRow(rowNum);
                for(int i=0;i<headerLength;i++){
                    HSSFCell cellHeader = title2.createCell(i);
                    cellHeader.setCellStyle(titlestyle); 
                    cellHeader.setCellValue(title);
                }
                sheet.addMergedRegion(new CellRangeAddress(rowNum-1,rowNum,0,headerLength-1));
            }
            
            //表头
            for (int i = 0; i < header.size(); i++) {
                //行
                rowNum ++;
                HSSFRow row = sheet.createRow(rowNum);
                List<CellInfo> cols = header.get(i);
                //创建列
                int colNum = 0;
                for(int j=0;j<cols.size();j++){
                    HSSFCell cell = row.createCell(colNum);   
                    cell.setCellStyle(titlestyle);   
                    cell.setCellValue(cols.get(j).getContent());
                    int firstRow = rowNum;
                    int lastRow =rowNum;
                    int firstCol = colNum;
                    int lastCol = colNum;
                    boolean merge = false;
                    if(cols.get(j).getRowSpan()>1){
                        lastRow += cols.get(j).getRowSpan()-1;
                        merge = true;
                    }
                    //如果跨行则先创建被合并的单元格（主要是不创建的话，合并后的样式引用有问题）
                    if(cols.get(j).getColSpan()>1){
                        for(int k=0;k<cols.get(j).getColSpan()-1;k++){
                            colNum++;
                            HSSFCell tmpCell = row.createCell(colNum);   
                            tmpCell.setCellStyle(titlestyle);   
                            tmpCell.setCellValue(cols.get(j).getContent());
                        }
                        lastCol = colNum;
                        merge = true;
                    }
                    colNum++;
                    if(merge){
                        sheet.addMergedRegion(new CellRangeAddress(firstRow,lastRow,firstCol,lastCol));
                    }
                }
             }   
            //表格数据
             for (int i = 0; i < data.size(); i++) {
                //行
                rowNum ++;
                HSSFRow row = sheet.createRow(rowNum);
                List<CellInfo> cols = data.get(i);
                //创建列
                int colNum = 0;
                for(int j=0;j<cols.size();j++){
                    HSSFCell cell = row.createCell(colNum);   
                    cell.setCellStyle(style);   
                    cell.setCellValue(cols.get(j).getContent());
                    int firstRow = rowNum;
                    int lastRow =rowNum;
                    int firstCol = colNum;
                    int lastCol = colNum;
                    boolean merge = false;
                    if(cols.get(j).getRowSpan()>1){
                        lastRow += cols.get(j).getRowSpan()-1;
                        merge = true;
                    }
                    //如果跨行则先创建被合并的单元格（主要是不创建的话，合并后的样式引用有问题）
                    if(cols.get(j).getColSpan()>1){
                        for(int k=0;k<cols.get(j).getColSpan()-1;k++){
                            colNum++;
                            HSSFCell tmpCell = row.createCell(colNum);   
                            tmpCell.setCellStyle(style);   
                            tmpCell.setCellValue(cols.get(j).getContent());
                        }
                        lastCol = colNum;
                        merge = true;
                    }
                    colNum++;
                    if(merge){
                        sheet.addMergedRegion(new CellRangeAddress(firstRow,lastRow,firstCol,lastCol));
                    }
                }
             }
             rowNum++;
             
             //页底样式
            HSSFCellStyle footerStyle = workbook.createCellStyle();// 创建样式对象 
            footerStyle.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 垂直居中 
            footerStyle.setAlignment(HSSFCellStyle.ALIGN_LEFT);
            footerStyle.setFont(font);
            
             int n = headerLength/4;
             int m = headerLength%4;
             int start = 0;
             int end = n;
             HSSFRow footer = sheet.createRow(rowNum);
             HSSFCell unitFooter = footer.createCell(0); 
             unitFooter.setCellStyle(footerStyle); 
             unitFooter.setCellValue("填报单位：");
             
             if(m>0){
                 end += 1;
             }
             sheet.addMergedRegion(new CellRangeAddress(rowNum,rowNum+1,start,end-1));
             
             start = end;
            HSSFCell timeFooter = footer.createCell(start); 
            timeFooter.setCellStyle(footerStyle); 
            timeFooter.setCellValue("填报时间：");
            if(m>1){
                end += n+1;
            }else{
                end += n;
            }
            sheet.addMergedRegion(new CellRangeAddress(rowNum,rowNum+1,start,end-1));
             
            start = end;
            HSSFCell personFooter = footer.createCell(start); 
            personFooter.setCellStyle(footerStyle); 
            personFooter.setCellValue("填报人：");
            if(m>2){
                end += n+1;
            }else{
                end += n;
            }
             sheet.addMergedRegion(new CellRangeAddress(rowNum,rowNum+1,start,end-1));
             
             start = end;
            HSSFCell telFooter = footer.createCell(start); 
            telFooter.setCellStyle(footerStyle); 
            telFooter.setCellValue("联系电话：");
             sheet.addMergedRegion(new CellRangeAddress(rowNum,rowNum+1,start,headerLength-1));
        }
        return workbook;
     }    
    
    /**
     * 解决 导出excel 文件名 为中文时乱码的问题
     * @param fileName 文件名
     * @return
     */
    public static String toUtf8String(String fileName) {
        try {
            return new String(fileName.getBytes("GBK"), "ISO8859-1");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return fileName;
    }

/**
 * 
 * 表格内容信息
 * <p>
 * 表格类每个单元格信息
 * </p>
 * @author qinwb
 * @since jdk1.7
 * 2017年3月21日
 *
 */

public class CellInfo {
    
    /**
     * 内容:默认为空
     */
    private String content = "";
    /**
     * 跨列:默认跨1列
     */
    private int colSpan = 1;
    /**
     * 跨行:默认跨1行
     */
    private int rowSpan = 1;
    
    public String getContent() {
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }
    public int getColSpan() {
        return colSpan;
    }
    public void setColSpan(int colSpan) {
        this.colSpan = colSpan;
    }
    public int getRowSpan() {
        return rowSpan;
    }
    public void setRowSpan(int rowSpan) {
        this.rowSpan = rowSpan;
    }
    public CellInfo() {
    }
    public CellInfo(String content, int rowSpan, int colSpan) {
        super();
        this.content = content;
        this.rowSpan = rowSpan;
        this.colSpan = colSpan;
    }
    public CellInfo(String content) {
        super();
        this.content = content;
    }
}