java poi技术操作excel之向Excel中写入值

原文地址https://blog.csdn.net/u013068377/article/details/52164499

 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 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;
     }
 }