使用POI读写EXCEL文件

读SHEET内容：

写入红框中内容：

 

执行结果：

 

导入jar包：

 

类和代码：

 package com.itcast.poi.helloworld;

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.math.BigDecimal;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;

 import org.apache.poi.ss.usermodel.Cell;
 import org.apache.poi.ss.usermodel.CellStyle;
 import org.apache.poi.ss.usermodel.DataFormat;
 import org.apache.poi.ss.usermodel.DateUtil;
 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.ss.usermodel.WorkbookFactory;

 import com.itcast.poi.util.NumberUtils;

 /**
  * POI3.9版本 工具类 版本01
  * @author 吕鹏
  * @date 2012-12-22
  */
 public class PoiHelloworld {
     static SimpleDateFormat sFormat = new SimpleDateFormat("yyyy-MM-dd");
     static Map styleMap = new HashMap(); //存储单元格样式的Map


     public static void main(String[] args) {
         /**
          * 读文件
          */
         readExcel("D:/a.xlsx");

         /**
          * 写文件
          */
         testWrite("D:/a.xlsx","D:/b.xlsx");
     }

     /**
      * 读excel
      * @param filePath excel路径
      */
     public static  void readExcel(String filePath){
         Workbook book = null;
         try {
             book = getExcelWorkbook(filePath);
             Sheet sheet = getSheetByNum(book,1);
             System.out.println("sheet名称是："+sheet.getSheetName());

             int lastRowNum = sheet.getLastRowNum();

             Row row = null;
             for(int i=0;i<=lastRowNum;i++){
                 row = sheet.getRow(i);
                 if(row != null){
                     System.out.println("正在读第"+(i+1)+"行：");
                     int lastCellNum = row.getLastCellNum();
                     Cell cell = null;
                     StringBuilder sb = null;
                     for(int j=0;j
                         cell = row.getCell(j);
                         if(cell != null){
                             sb = new StringBuilder("第"+(j+1)+"列的单元格内容是：");
                             String type_cn = null;
                             String type_style = cell.getCellStyle().getDataFormatString().toUpperCase();
                             String type_style_cn = getCellStyleByChinese(type_style);
                             int type = cell.getCellType();
                             String value = "";
                             switch (type) {
                                 case 0:
                                     if(DateUtil.isCellDateFormatted(cell)){
                                         type_cn = "NUMBER-DATE";
                                         Date date = cell.getDateCellValue();
                                         value = sFormat.format(date);
                                     }else {
                                         type_cn = "NUMBER";
                                         double tempValue = cell.getNumericCellValue();
                                         value = String.valueOf(tempValue);
                                     }
                                     break;
                                 case 1:
                                     type_cn = "STRING";
                                     value = cell.getStringCellValue();
                                     break;
                                 case 2:
                                     type_cn = "FORMULA";
                                     value = cell.getCellFormula();
                                     break;
                                 case 3:
                                     type_cn = "BLANK";
                                     value = cell.getStringCellValue();
                                     break;
                                 case 4:
                                     type_cn = "BOOLEAN";
                                     boolean tempValue = cell.getBooleanCellValue();
                                     value = String.valueOf(tempValue);
                                     break;
                                 case 5:
                                     type_cn = "ERROR";
                                     byte b = cell.getErrorCellValue();
                                     value = String.valueOf(b);
                                 default:
                                     break;
                             }
                             sb.append(value + ",内容类型是："+type_cn+",单元格的格式是："+type_style_cn);
                             System.out.println(sb.toString());
                         }
                     }
                 }
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
     }


     /**
      * 根据单元格的格式 返回单元格的格式中文
      * @param type_style
      * @return
      */
     private static String getCellStyleByChinese(String type_style) {
         String cell_style_cn = "";
         if(type_style.contains("GENERAL")){
             cell_style_cn = "常规";
         }else if(type_style.equals("_ * #,##0.00_ ;_ * \\-#,##0.00_ ;_ * \"-\"??_ ;_ @_ ")){
             cell_style_cn = "会计专用";
         }else if(type_style.equals("0")){
             cell_style_cn = "整数";
         }else if(type_style.contains("YYYY/MM") || type_style.contains("YYYY\\-MM")){
             cell_style_cn = "日期";
         }else if(type_style.equals("0.00%")){
             cell_style_cn = "百分比";
         }else {
             cell_style_cn = "不符合规定格式类型:"+type_style;
 //          cell_style_cn = type_style;
         }
         return cell_style_cn;
     }


     /**
      * 写内容到excel中
      * @throws IOException
      */
     public static void testWrite(String srcFilePath,String tarFilePath){
         FileOutputStream out = null;
         try {
             Workbook book = getExcelWorkbook(srcFilePath);
             Sheet sheet = getSheetByNum(book,1);

             Map map = new HashMap();
             List> list = new LinkedList>();
             map.put("A", "4,INT");
             map.put("B", "小红,GENERAL");
             map.put("C", "18,INT");
             map.put("D", "1990-03-10,DATE");
             map.put("E", "0.056,PERCENT");
             map.put("F", "4800,DOUBLE");
             list.add(map);

             int startRow = 6;
             boolean result = writeToExcel(list, sheet,startRow);
             if(result){
                 out = new FileOutputStream(tarFilePath);
                 book.write(out);
                 System.out.println("文件写入完成！");
             }
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             try {
                 out.close();
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
     }

     /**
      * 将传入的内容写入到excel中sheet里
      * @param list
      */
     public static boolean writeToExcel(List> list,Sheet sheet,int startRow){
         boolean result = false;
         try {
             Map map = null;
             Row row = null;
             for(int i=0;i
                 map = list.get(i);
                 row = sheet.getRow(startRow-1);
                 if(row == null){
                     row = sheet.createRow(startRow-1);
                 }
                 startRow ++;
                 Cell cell = null;

                 BigDecimal db = null;
                 for(Map.Entry entry : map.entrySet()){
                     String key = entry.getKey();
                     int colNum = NumberUtils.toNum_new(key)-1;

                     String value_type = entry.getValue();
                     String value = value_type.split(",")[0];
                     String style = value_type.split(",")[1];

                     cell = row.getCell(colNum);
                     if(cell == null){
                         cell = row.createCell(colNum);
                     }
                     if(style.equals("GENERAL")){
                         cell.setCellValue(value);
                     }else{
                         if(style.equals("DOUBLE") || style.equals("INT")){
                             db = new BigDecimal(value,java.math.MathContext.UNLIMITED);
                             cell.setCellValue(db.doubleValue());
                         }else if(style.equals("PERCENT")){
                             db = new BigDecimal(value,java.math.MathContext.UNLIMITED);
                             cell.setCellValue(db.doubleValue());
                         }else if(style.equals("DATE")){
                             java.util.Date date = sFormat.parse(value);
                             cell.setCellValue(date);
                         }
                         cell.setCellStyle(styleMap.get(style));
                     }
                 }
             }
             result = true;
         } catch (Exception e) {
             e.printStackTrace();
             throw new RuntimeException(e.getMessage());
         }
         return result;
     }
     /**
      * 获取excel的Workbook
      * @throws IOException
      */
     public static Workbook getExcelWorkbook(String filePath) throws IOException{
         Workbook book = null;
         File file  = null;
         FileInputStream fis = null;

         try {
             file = new File(filePath);
             if(!file.exists()){
                 throw new RuntimeException("文件不存在");
             }else{
                 fis = new FileInputStream(file);
                 book = WorkbookFactory.create(fis);
                 initStyleMap(book);
             }
         } catch (Exception e) {
             throw new RuntimeException(e.getMessage());
         } finally {
             if(fis != null){
                 fis.close();
             }
         }
         return book;
     }

     /**
      * 根据索引 返回Sheet
      * @param number
      */
     public static Sheet getSheetByNum(Workbook book,int number){
         Sheet sheet = null;
         try {
             sheet = book.getSheetAt(number-1);
 //          if(sheet == null){
 //              sheet = book.createSheet("Sheet"+number);
 //          }
         } catch (Exception e) {
             throw new RuntimeException(e.getMessage());
         }
         return sheet;
     }

     /**
      * 初始化格式Map
      */


     public static void initStyleMap(Workbook book){
         DataFormat hssfDF = book.createDataFormat();

         CellStyle doubleStyle = book.createCellStyle(); //会计专用
         doubleStyle.setDataFormat(hssfDF.getFormat("_ * #,##0.00_ ;_ * \\-#,##0.00_ ;_ * \"-\"??_ ;_ @_ ")); //poi写入后为会计专用
         styleMap.put("DOUBLE", doubleStyle);

         CellStyle intStyle = book.createCellStyle(); //会计专用
         intStyle.setDataFormat(hssfDF.getFormat("0")); //poi写入后为会计专用
         styleMap.put("INT", intStyle);

         CellStyle yyyyMMddStyle = book.createCellStyle();//日期yyyyMMdd
         yyyyMMddStyle.setDataFormat(hssfDF.getFormat("yyyy-MM-dd"));
         styleMap.put("DATE", yyyyMMddStyle);

         CellStyle percentStyle = book.createCellStyle();//百分比
         percentStyle.setDataFormat(hssfDF.getFormat("0.00%"));
         styleMap.put("PERCENT", percentStyle);
     }
 }

 

 附加上 数字转字母的方法：

 public static String toLetterString(int number) {
         if (number < 1) {//
             return null;
         }
         if (number < 27) {
             return String.valueOf((char) ('A' + number - 1));
         }
         if (number % 26 == 0) {
             return toLetterString(number / 26 - 1) + "Z";
         }
         return toLetterString(number / 26)+ String.valueOf((char) ('A' + number % 26 - 1));
     }

 

源代码地址：

http://download.csdn.net/detail/qq522935502/4986839 

文章来自：http://blog.csdn.net/qq522935502/article/details/8374118