java合并单元格同时导出excel

POI进行跨行需要用到对象HSSFSheet对象，现在就当我们程序已经定义了一个HSSFSheet对象sheet。 

跨第1行第1个到第2个单元格的操作为 
sheet.addMergedRegion(new Region(0,(short)0,0,(short)1)); 

跨第1行第1个到第2行第1个单元格的操作为 
sheet.addMergedRegion(new Region(0,(short)0,1,(short)0)); 


重点注意事项： 
1.单元格CELL和ROW对象下标都是从0开始的。 
2.单元格合并时Region(1,2,3,4)第1个值的行号必须要比3位置的行号小，如果大于3就不能正常合并单元格 
3.合并单元格的时候要合并的单单元格必须先创建，这样方便后面再次获取这个单元格来填充数据，主要就是因为合并时不能由后向前进行合并引起的。 

import java.io.IOException;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.util.Region;


public class ExcelTest {

    /**
     * @param args
     */
    public static void main(String[] args) throws IOException {

        try {
            HSSFWorkbook wb = new HSSFWorkbook();
            HSSFSheet sheet = wb.createSheet("new   sheet");
            HSSFCellStyle style = wb.createCellStyle(); // 样式对象

            style.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 垂直
            style.setAlignment(HSSFCellStyle.ALIGN_CENTER);// 水平
            HSSFRow row = sheet.createRow((short) 0);
            HSSFRow row2 = sheet.createRow((short) 1);

            sheet.addMergedRegion(new Region(0, (short) 0, 1, (short) 0));
            HSSFCell ce = row.createCell((short) 0);
            ce.setEncoding(HSSFCell.ENCODING_UTF_16);// 中文处理
            ce.setCellValue("项目\\日期"); // 表格的第一行第一列显示的数据
            ce.setCellStyle(style); // 样式，居中
            int num = 0;
            for (int i = 0; i < 9; i++) { // 循环9次，每一次都要跨单元格显示
                // 计算从那个单元格跨到那一格
                int celln = 0;
                int celle = 0;
                if (i == 0) {
                    celln = 0;
                    celle = 1;
                } else {
                    celln = (i * 2);
                    celle = (i * 2 + 1);
                }
                // 单元格合并
                // 四个参数分别是：起始行，起始列，结束行，结束列
                sheet.addMergedRegion(new Region(0, (short) (celln + 1), 0,
                        (short) (celle + 1)));
                HSSFCell cell = row.createCell((short) (celln + 1));
                cell.setCellValue("merging" + i); // 跨单元格显示的数据
                cell.setCellStyle(style); // 样式
                // 不跨单元格显示的数据，如：分两行，上一行分别两格为一格，下一行就为两格，“数量”，“金额”
                HSSFCell cell1 = row2.createCell((short) celle);
                HSSFCell cell2 = row2.createCell((short) (celle + 1));
                cell1.setEncoding(HSSFCell.ENCODING_UTF_16);
                cell1.setCellValue("数量");
                cell1.setCellStyle(style);
                cell2.setEncoding(HSSFCell.ENCODING_UTF_16);
                cell2.setCellValue("金额");
                cell2.setCellStyle(style);
                num++;
            }

            // 在后面加上合计百分比

            // 合计 在最后加上，还要跨一个单元格
            sheet.addMergedRegion(new Region(0, (short) (2 * num + 1), 0,
                    (short) (2 * num + 2)));
            HSSFCell cell = row.createCell((short) (2 * num + 1));
            cell.setEncoding(HSSFCell.ENCODING_UTF_16);
            cell.setCellValue("合计");
            cell.setCellStyle(style);
            HSSFCell cell1 = row2.createCell((short) (2 * num + 1));
            HSSFCell cell2 = row2.createCell((short) (2 * num + 2));
            cell1.setEncoding(HSSFCell.ENCODING_UTF_16);
            cell1.setCellValue("数量");
            cell1.setCellStyle(style);
            cell2.setEncoding(HSSFCell.ENCODING_UTF_16);
            cell2.setCellValue("金额");
            cell2.setCellStyle(style);

            // 百分比 同上
            sheet.addMergedRegion(new Region(0, (short) (2 * num + 3), 0,
                    (short) (2 * num + 4)));
            HSSFCell cellb = row.createCell((short) (2 * num + 3));
            cellb.setEncoding(HSSFCell.ENCODING_UTF_16);

            cellb.setCellValue("百分比");
            cellb.setCellStyle(style);

            HSSFCell cellb1 = row2.createCell((short) (2 * num + 3));
            HSSFCell cellb2 = row2.createCell((short) (2 * num + 4));
            cellb1.setEncoding(HSSFCell.ENCODING_UTF_16);
            cellb1.setCellValue("数量");
            cellb1.setCellStyle(style);
            cellb2.setEncoding(HSSFCell.ENCODING_UTF_16);
            cellb2.setCellValue("金额");
            cellb2.setCellStyle(style);

            /***这里是问题的关键，将这个工作簿写入到一个流中就可以输出相应的名字，这里需要写路径就ok了。
            FileOutputStream fileOut = new FileOutputStream("workbook.xls");
            wb.write(fileOut);
            fileOut.close();
             **/


            /**第二种是输出到也面中的excel名称
             * pName="栏目统计表";
    response.reset();
    response.setContentType("application/x-msdownload");
    response.setHeader("Content-Disposition","attachment; filename="+new String(pName.getBytes("gb2312"),"ISO-8859-1")+".xls");
    ServletOutputStream outStream=null;

    try{
        outStream = response.getOutputStream();
        wb.write(outStream);
    }catch(Exception e)
    {
     e.printStackTrace();
    }finally{
        outStream.close();
    }
             * */
            System.out.print("OK");
        } catch (Exception ex) {
            ex.printStackTrace();
        }

    }

}