Java 导入excel数据

package com.sccf.common.util;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;
import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

/**
 * 描述:
 * 导出excel
 *
 * @author W
 * @create 2018-11-02 15:46
 */
public class ExportExcelUtil {
   public void ExportWithResponse(String title, String fileName,
                           String[] titleName,String[] columnName, List dataList,
                           HttpServletResponse response) throws Exception {

      XSSFWorkbook wb = createXssfWorkBook();
      Sheet sheet = createSheet(wb, title, titleName);
      CellStyle cellStyle = createCellStyle(wb);
      for (int i = 0; i < dataList.size(); i++) {
         Row row= sheet.createRow(i+2);
         Object obj = dataList.get(i);
         Class clazz = obj.getClass();
         //创建单元格并设置单元格内容
         for (int k = 0; k < columnName.length; k++) {
            Cell cell = row.createCell(k);
            Field field = clazz.getDeclaredField(columnName[k]);
            //设置对象的访问权限，保证对private的属性的访问
            field.setAccessible(true);
            Object o = field.get(obj);
            if(null!=o){
               if(o instanceof Date){
                  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
                        cell.setCellValue(sdf.format(o));
               }else if(o instanceof BigDecimal){
                        cell.setCellValue(String.valueOf(((BigDecimal) o).setScale(2,BigDecimal.ROUND_CEILING)));
               }else if(o instanceof Integer) {
                        cell.setCellValue(o.toString());
               } else if (o instanceof Float) {
                        cell.setCellValue(o.toString());
               } else if (o instanceof Double) {
                        cell.setCellValue(o.toString());
               } else if (o instanceof Long) {
                        cell.setCellValue(o.toString());
               }else{
                        cell.setCellValue(String.valueOf(o));
               }
                    cell.setCellStyle(cellStyle);
            }
         }
      }

        downWrite(response,wb,fileName);
   }

    //创建HSSFWorkbook(2003)
    public HSSFWorkbook createHssfWorkBook(){
        HSSFWorkbook wb = new HSSFWorkbook();
        return wb;
    }

   //创建XSSFWorkbook(2007)
   public XSSFWorkbook createXssfWorkBook(){
      XSSFWorkbook xb = new XSSFWorkbook();
      return xb;
   }

   //创建sheet页面,标题
   public Sheet createSheet(Workbook xb,String sheetName,String [] titleName) {
      //建立新的sheet对象（excel的表单）
      Sheet sheet = xb.createSheet(sheetName);
      sheet.setDefaultColumnWidth(17);    //设置默认列宽，实际上回多出2个字符
      sheet.setDefaultRowHeight((short) (2 * 256)); //设置默认行高，表示2个字符的高度

        Row row1 = sheet.createRow(0);
      Cell cell = row1.createCell(0);
      cell.setCellValue(sheetName);
      //合并单元格CellRangeAddress构造参数依次表示起始行，截至行，起始列， 截至列
      sheet.addMergedRegion(new CellRangeAddress(0,0,0,titleName.length-1));
      cell.setCellStyle(createCellStyle(xb,1));

      //在sheet里创建第二行标题
      Row row2 = sheet.createRow(1);
      CellStyle cellStyle = createCellStyle(xb, 2);
      for (int j = 0; j < titleName.length; j++) {
         Cell cell2 = row2.createCell(j);
         cell2.setCellValue(titleName[j]);
         cell2.setCellStyle(cellStyle);
      }
      return  sheet;
   }

   public CellStyle createCellStyle(Workbook xb){
      return createCellStyle(xb,3);
   }

   //单元格样式
   public CellStyle createCellStyle(Workbook xb,int i){
      CellStyle cellStyle = xb.createCellStyle();
      Font fontStyle = xb.createFont();
      if(i==1){
         fontStyle.setFontHeightInPoints((short) 16);
      }else if(i==2){
         fontStyle.setFontHeightInPoints((short) 12);
         fontStyle.setBold(true);
      }else{
         fontStyle.setFontHeightInPoints((short) 10);
      }
      cellStyle.setFont(fontStyle);
      cellStyle.setAlignment(HorizontalAlignment.CENTER); // 居中
      cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);//垂直
      cellStyle.setWrapText(true);//自动换行
      return  cellStyle;
   }

   //下载
   public void  downWrite(HttpServletResponse response,Workbook xb,String fileName)throws Exception{
      if(xb instanceof HSSFWorkbook){
         fileName += ".xls";
      }
      if(xb instanceof  XSSFWorkbook){
         fileName += ".xlsx";
      }
      response.setContentType("application/ms-excel;charset=UTF-8");
      response.setHeader("Content-Disposition", "attachment;filename=" .concat(String.valueOf(URLEncoder.encode(fileName, "UTF-8"))));
      OutputStream out = response.getOutputStream();
      try {
         xb.write(out);// 将数据写出去
      } finally {
         out.close();
      }
   }

}