Java开发之导出excel工具类详解编程语言

web开发中，一个系统的普通需求也包括导出excel，一般采用POI做统计报表导出excel。

导出excel工具类：

    import java.io.FileOutputStream;   
    import java.io.IOException;   
    import java.io.OutputStream;   
    import java.util.List;   
    import java.util.Map;   
       
    import org.apache.poi.hssf.usermodel.HSSFCell;   
    import org.apache.poi.hssf.usermodel.HSSFRichTextString;   
    import org.apache.poi.hssf.usermodel.HSSFRow;   
    import org.apache.poi.hssf.usermodel.HSSFSheet;   
    import org.apache.poi.hssf.usermodel.HSSFWorkbook;   
       
    public class ExportExcel {   
       
        private ExportExcel() {   
            super();   
        }   
       
        public static void exportExcel(List<Object> list, Map<Integer, Long> map,   
                String[] titles) throws IOException {   
            // 创建Excel文档   
            HSSFWorkbook hwb = new HSSFWorkbook();   
            // sheet 对应一个工作页   
            HSSFSheet sheet = hwb.createSheet("exportReport");   
            int colNum = titles.length;   
            // 创建第一行   
            HSSFRow firstrow = sheet.createRow(0);   
            HSSFCell[] firstcell = new HSSFCell[colNum];   
            for (int col = 0; col < colNum; col++) {   
                firstcell[col] = firstrow.createCell(col);   
                firstcell[col].setCellValue(new HSSFRichTextString(titles[col]));   
            }   
       
            // 插入记录   
            int rowNum = map.size();   
            for (int i = 0; i < rowNum; i++) {   
                // 从第二行开始   
                HSSFRow row = sheet.createRow(i + 1);   
                // 插入list中的字段   
                for (int col = 0; col < colNum - 2; col++) {   
                    HSSFCell cell = row.createCell(col);   
                    cell.setCellValue(list.get(col).toString());   
                }   
                // 插入月份或日期   
                row.createCell(colNum - 2).setCellValue(i + 1);   
                // 插入总量   
                row.createCell(colNum - 1).setCellValue(map.get(i + 1));   
            }   
            String fileName = titles[1].substring(0, 2);   
            if (colNum == 4) {   
                fileName += list.get(0) + "_" + list.get(1) + "年_年度报表";   
            } else if (colNum == 5) {   
                fileName += list.get(0) + "_" + list.get(1) + "年" + list.get(2)   
                        + "月_月度报表";   
            }   
            // 创建文件输出流，准备输出电子表格   
            OutputStream out = new FileOutputStream("../webapps/UsedMallMinaServer/files/"   
                    + fileName + ".xls");   
            hwb.write(out);   
            out.close();   
        }   
    }