POI读取/写入Excel文件

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;

 import org.apache.poi.hssf.usermodel.HSSFCell;
 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.HSSFColor;
 import org.apache.poi.ss.usermodel.CellStyle;
 import org.apache.poi.xssf.usermodel.XSSFCell;
 import org.apache.poi.xssf.usermodel.XSSFCellStyle;
 import org.apache.poi.xssf.usermodel.XSSFFont;
 import org.apache.poi.xssf.usermodel.XSSFRow;
 import org.apache.poi.xssf.usermodel.XSSFSheet;
 import org.apache.poi.xssf.usermodel.XSSFWorkbook;

 /**
  *
  * @Description :POI读取/创建Excel文件
  * @author : James
  * @version : 1.0
  * @Date : 2016年3月2日 下午2:18:27
  */
 public class ExcelManager {

     private HSSFWorkbook hssfWorkbook;
     private XSSFWorkbook xssfWorkbook;

     /**
      * 读取Excel2010版
      *
      * @param inputStream输入流
      * @return
      */
     public List<String[]> readXlsx(InputStream inputStream) {
         List<String[]> result = new ArrayList<>();
         try {
             xssfWorkbook = new XSSFWorkbook(inputStream);
             for (int numSheet = 0; numSheet < xssfWorkbook.getNumberOfSheets(); numSheet++) {
                 XSSFSheet xssfSheet = xssfWorkbook.getSheetAt(numSheet);
                 if (xssfSheet == null) {
                     continue;
                 }
                 for (int rowNum = 1; rowNum <= xssfSheet.getLastRowNum(); rowNum++) {
                     XSSFRow xssfRow = xssfSheet.getRow(rowNum);
                     if (xssfRow != null) {
                         String[] row = new String[xssfSheet.getRow(1).getLastCellNum()]; // 以第一列值行为标准
                         for (int i = 0; i < row.length; i++) {
                             row[i] = getValue(xssfRow.getCell(i));
                         }
                         result.add(row);
                     }
                 }
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
         return result;
     }

     /**
      * 读取Excel2003/2007版
      *
      * @param inputStream输入流
      * @return
      */
     public List<String[]> readXls(InputStream inputStream) {
         List<String[]> result = new ArrayList<>();
         try {
             hssfWorkbook = new HSSFWorkbook(inputStream);
             for (int numSheet = 0; numSheet < hssfWorkbook.getNumberOfSheets(); numSheet++) {
                 HSSFSheet hssfSheet = hssfWorkbook.getSheetAt(numSheet);
                 if (hssfSheet == null) {
                     continue;
                 }
                 for (int rowNum = 1; rowNum <= hssfSheet.getLastRowNum(); rowNum++) {
                     HSSFRow hssfRow = hssfSheet.getRow(rowNum);
                     if (hssfRow != null) {
                         String[] row = new String[hssfSheet.getRow(1).getLastCellNum()];
                         for (int i = 0; i < row.length; i++) {
                             row[i] = getValue(hssfRow.getCell(i));
                         }
                         result.add(row);
                     }
                 }
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
         return result;
     }

     public List<String[]> readXlsx(File file) {
         List<String[]> result = new ArrayList<>();
         try {
             xssfWorkbook = new XSSFWorkbook(file);
             for (int numSheet = 0; numSheet < xssfWorkbook.getNumberOfSheets(); numSheet++) {
                 XSSFSheet xssfSheet = xssfWorkbook.getSheetAt(numSheet);
                 if (xssfSheet == null) {
                     continue;
                 }
                 for (int rowNum = 1; rowNum <= xssfSheet.getLastRowNum(); rowNum++) {
                     XSSFRow xssfRow = xssfSheet.getRow(rowNum);
                     if (xssfRow != null) {
                         String[] row = new String[xssfSheet.getRow(1).getLastCellNum()]; // 以第一列值行为标准
                         for (int i = 0; i < row.length; i++) {
                             row[i] = getValue(xssfRow.getCell(i));
                         }
                         result.add(row);
                     }
                 }
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
         return result;
     }

     private String getValue(XSSFCell xssfRow) {
         if (xssfRow == null)
             return "";
         if (xssfRow.getCellType() == xssfRow.CELL_TYPE_BOOLEAN) {
             return String.valueOf(xssfRow.getBooleanCellValue());
         } else if (xssfRow.getCellType() == xssfRow.CELL_TYPE_NUMERIC) {
             return String.valueOf(xssfRow.getNumericCellValue());
         } else {
             return String.valueOf(xssfRow.getStringCellValue().trim());
         }
     }

     private String getValue(HSSFCell hssfCell) {
         if (hssfCell == null)
             return "";
         if (hssfCell.getCellType() == hssfCell.CELL_TYPE_BOOLEAN) {
             return String.valueOf(hssfCell.getBooleanCellValue());
         } else if (hssfCell.getCellType() == hssfCell.CELL_TYPE_NUMERIC) {
             return String.valueOf(hssfCell.getNumericCellValue());
         } else {
             return String.valueOf(hssfCell.getStringCellValue().trim());
         }
     }

     /**
      * 重新创建新Excel文件
      *
      * @return
      */
     public String createNewExcel(File file, String newFilePath, String[] title) {
         try {
             InputStream inputStream = new FileInputStream(file);
             // 文件类型
             String fileType = file.getName().substring(file.getName().lastIndexOf(".") + 1, file.getName().length());
             List<String[]> objList = null;
             if ("xlsx".equals(fileType)) {
                 objList = readXlsx(inputStream);
             } else if ("xls".equals(fileType)) {
                 objList = readXls(inputStream);
             }
             // 创建Excel的工作书册 Workbook,对应到一个excel文档
             XSSFWorkbook wb = new XSSFWorkbook();
             // 创建Excel的工作sheet,对应到一个excel文档的tab
             XSSFSheet sheet = wb.createSheet("sheet1");
             sheet.setColumnWidth(0, 5500);// 设置单元格宽度，这里设置第一列的宽度
             XSSFRow firstRow = sheet.createRow(0);
             // 设置字体
             XSSFFont font = wb.createFont();
             font.setBold(true);// 粗体字
             font.setColor(HSSFColor.RED.index);
             font.setFontName("宋体");
             // 设置单元格属性
             CellStyle cellStyle = wb.createCellStyle();
             cellStyle.setFont(font);// 设置字体
             cellStyle.setFillBackgroundColor(HSSFColor.LIGHT_YELLOW.index);
             cellStyle.setFillForegroundColor(HSSFColor.LIGHT_YELLOW.index);
             cellStyle.setFillPattern(XSSFCellStyle.SOLID_FOREGROUND);
             // 生成表头
             for (int i = 0; i < title.length; i++) {
                 XSSFCell cell = firstRow.createCell(i);
                 cell.setCellValue(title[i]);
                 cell.setCellStyle(cellStyle);// 设置单元格背景
             }
             // 生成数据
             for (int i = 0; i < objList.size(); i++) {
                 String[] lineObj = objList.get(i);
                 XSSFRow row = sheet.createRow(i + 1);// 因为表头已经占用了第一行，所以后面生成的行需从第二行开始
                 for (int j = 0; j < lineObj.length; j++) {
                     XSSFCell cell = row.createCell(j);
                     cell.setCellValue(lineObj[j].toString());
                 }
             }
             FileOutputStream os = new FileOutputStream(newFilePath);
             wb.write(os);
             os.close();
         } catch (Exception e) {
             e.printStackTrace();
         }
         return null;
     }

     public static void main(String[] args) {
         String[] title = { "姓名", "年龄", "性别", "岗位", "入职年份" };
         ExcelManager em = new ExcelManager();
         em.createNewExcel(new File("D:\\用户信息.xlsx"), "D:\\new_excel.xlsx", title);
     }

 }

效果图

原Excel文件：

生成后：