java-poi-write-excle

    import java.io.File;  
    import java.io.FileInputStream;  
    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.HSSFWorkbook;  
    import org.apache.poi.ss.usermodel.Cell;  
    import org.apache.poi.ss.usermodel.Row;  
    import org.apache.poi.ss.usermodel.Sheet;  
    import org.apache.poi.ss.usermodel.Workbook;  
    import org.apache.poi.xssf.usermodel.XSSFWorkbook;  
      
    public class WriteExcel {  
        private static final String EXCEL_XLS = "xls";  
        private static final String EXCEL_XLSX = "xlsx";  
      
        public static void writeExcel(List<Map> dataList, int cloumnCount,String finalXlsxPath){  
            OutputStream out = null;  
            try {  
                // 获取总列数  
                int columnNumCount = cloumnCount;  
                // 读取Excel文档  
                File finalXlsxFile = new File(finalXlsxPath);  
                Workbook workBook = getWorkbok(finalXlsxFile);  
                // sheet 对应一个工作页  
                Sheet sheet = workBook.getSheetAt(0);  
                /** 
                 * 删除原有数据，除了属性列 
                 */  
                int rowNumber = sheet.getLastRowNum();  // 第一行从0开始算  
                System.out.println("原始数据总行数，除属性列：" + rowNumber);  
                for (int i = 1; i <= rowNumber; i++) {  
                    Row row = sheet.getRow(i);  
                    sheet.removeRow(row);  
                }  
                // 创建文件输出流，输出电子表格：这个必须有，否则你在sheet上做的任何操作都不会有效  
                out =  new FileOutputStream(finalXlsxPath);  
                workBook.write(out);  
                /** 
                 * 往Excel中写新数据 
                 */  
                for (int j = 0; j < dataList.size(); j++) {  
                    // 创建一行：从第二行开始，跳过属性列  
                    Row row = sheet.createRow(j + 1);  
                    // 得到要插入的每一条记录  
                    Map dataMap = dataList.get(j);  
                    String name = dataMap.get("BankName").toString();  
                    String address = dataMap.get("Addr").toString();  
                    String phone = dataMap.get("Phone").toString();  
                    for (int k = 0; k <= columnNumCount; k++) {  
                    // 在一行内循环  
                    Cell first = row.createCell(0);  
                    first.setCellValue(name);  
              
                    Cell second = row.createCell(1);  
                    second.setCellValue(address);  
              
                    Cell third = row.createCell(2);  
                    third.setCellValue(phone);  
                    }  
                }  
                // 创建文件输出流，准备输出电子表格：这个必须有，否则你在sheet上做的任何操作都不会有效  
                out =  new FileOutputStream(finalXlsxPath);  
                workBook.write(out);  
            } catch (Exception e) {  
                e.printStackTrace();  
            } finally{  
                try {  
                    if(out != null){  
                        out.flush();  
                        out.close();  
                    }  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }  
            }  
            System.out.println("数据导出成功");  
        }  
      
        /** 
         * 判断Excel的版本,获取Workbook 
         * @param in 
         * @param filename 
         * @return 
         * @throws IOException 
         */  
        public static Workbook getWorkbok(File file) throws IOException{  
            Workbook wb = null;  
            FileInputStream in = new FileInputStream(file);  
            if(file.getName().endsWith(EXCEL_XLS)){  //Excel 2003  
                wb = new HSSFWorkbook(in);  
            }else if(file.getName().endsWith(EXCEL_XLSX)){  // Excel 2007/2010  
                wb = new XSSFWorkbook(in);  
            }  
            return wb;  
        }  
    }