Java项目中如何将Excel文件从数据库导入与导出

发布时间：2020-12-02 16:19:46 来源：亿速云阅读：251 作者：Leah 栏目：编程语言

本篇文章给大家分享的是有关Java项目中如何将Excel文件从数据库导入与导出，小编觉得挺实用的，因此分享给大家学习，希望大家阅读完这篇文章后可以有所收获，话不多说，跟着小编一起来看看吧。

ExcellToObjectUtil 类

主要功能是讲Excel中的数据导入到数据库中，有几个注意点就是

1.一般Excel中第一行是字段名称，不需要导入，所以从第二行开始计算

2.每列的匹配要和对象的属性一样

import java.io.IOException;
import java.text.DecimalFormat;
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.poifs.filesystem.POIFSFileSystem;
import com.forenms.exam.domain.ExamInfo;
public class ExcellToObjectUtil {
  //examId,realName,身份证,user_card,sex,没有字段,assessment_project,admission_number,seat_number
   /**
   * 读取xls文件内容
   * 
   * @return List<XlsDto>对象
   * @throws IOException
   *       输入/输出(i/o)异常
   */
  public static List<ExamInfo> readXls(POIFSFileSystem poifsFileSystem) throws IOException {
//    InputStream is = new FileInputStream(filepath);
    HSSFWorkbook hssfWorkbook = new HSSFWorkbook(poifsFileSystem);
    ExamInfo exam = null;
    List<ExamInfo> list = new ArrayList<ExamInfo>();
    // 循环工作表Sheet
    for (int numSheet = 0; numSheet < hssfWorkbook.getNumberOfSheets(); numSheet++) {
      HSSFSheet hssfSheet = hssfWorkbook.getSheetAt(numSheet);
      if (hssfSheet == null) {
        continue;
      }
      // 循环行Row
      for (int rowNum = 1; rowNum <= hssfSheet.getLastRowNum(); rowNum++) {
        HSSFRow hssfRow = hssfSheet.getRow(rowNum);
        if (hssfRow == null) {
          continue;
        }
        exam = new ExamInfo();
        // 循环列Cell
        HSSFCell examId = hssfRow.getCell(1);
        if (examId == null) {
          continue;
        }
        double id = Double.parseDouble(getValue(examId));
        exam.setExamId((int)id);
//        HSSFCell realName = hssfRow.getCell(2);
//        if (realName == null) {
//          continue;
//        }
//        exam.setRealName(getValue(realName));
//        HSSFCell userCard = hssfRow.getCell(4);
//        if (userCard == null) {
//          continue;
//        }
//        
//        exam.setUserCard(getValue(userCard));
        HSSFCell admission_number = hssfRow.getCell(8);
        if (admission_number == null) {
          continue;
        }
        exam.setAdmission_number(getValue(admission_number));
        HSSFCell seat_number = hssfRow.getCell(9);
        if (seat_number == null) {
          continue;
        }
        exam.setSeat_number(getValue(seat_number));
        list.add(exam);
      }
    }
    return list;
  }
  public static List<ExamInfo> readXlsForJS(POIFSFileSystem poifsFileSystem) throws IOException {
//   InputStream is = new FileInputStream(filepath);
   HSSFWorkbook hssfWorkbook = new HSSFWorkbook(poifsFileSystem);
   ExamInfo exam = null;
   List<ExamInfo> list = new ArrayList<ExamInfo>();
   // 循环工作表Sheet
   for (int numSheet = 0; numSheet < hssfWorkbook.getNumberOfSheets(); numSheet++) {
     HSSFSheet hssfSheet = hssfWorkbook.getSheetAt(numSheet);
     if (hssfSheet == null) {
       continue;
     }
     // 循环行Row
     for (int rowNum = 1; rowNum <= hssfSheet.getLastRowNum(); rowNum++) {
       HSSFRow hssfRow = hssfSheet.getRow(rowNum);
       if (hssfRow == null) {
         continue;
       }
       exam = new ExamInfo();
       // 循环列Cell 准考证号
       HSSFCell admission_number = hssfRow.getCell(0);
       if (admission_number == null) {
         continue;
       }
       exam.setAdmission_number(getValue(admission_number));
       //读取身份证号
       HSSFCell userCard= hssfRow.getCell(2);
       if (userCard == null) {
        continue;
       }
       exam.setUserCard(getValue(userCard));
       //读取座位号
       HSSFCell seat_number = hssfRow.getCell(3);
       if (seat_number == null) {
        continue;
       }
       exam.setSeat_number(getValue(seat_number));
       //读取考场号
       HSSFCell fRoomName = hssfRow.getCell(6);
       if (fRoomName == null) {
        continue;
       }
       exam.setfRoomName(getValue(fRoomName));
       //读取开考时间
       HSSFCell fBeginTime = hssfRow.getCell(8);
       if (fBeginTime == null) {
        continue;
       }
       exam.setfBeginTime(getValue(fBeginTime));
       //读取结束时间
       HSSFCell fEndTime = hssfRow.getCell(9);
       if (fEndTime == null) {
        continue;
       }
       exam.setfEndTime(getValue(fEndTime));
       list.add(exam);
     }
   }
   return list;
 }
  /**
   * 得到Excel表中的值
   * 
   * @param hssfCell
   *      Excel中的每一个格子
   * @return Excel中每一个格子中的值
   */
  private static String getValue(HSSFCell hssfCell) {
    if (hssfCell.getCellType() == HSSFCell.CELL_TYPE_BOOLEAN) {
      // 返回布尔类型的值
      return String.valueOf(hssfCell.getBooleanCellValue());
    } else if (hssfCell.getCellType() == HSSFCell.CELL_TYPE_NUMERIC) {
      // 返回数值类型的值
      DecimalFormat df = new DecimalFormat("0"); 
      String strCell = df.format(hssfCell.getNumericCellValue());
      return String.valueOf(strCell);
    } else {
      // 返回字符串类型的值
      return String.valueOf(hssfCell.getStringCellValue());
    }
  }
}

当然有导入功能，一定也有导出功能，下面介绍导出功能，直接上代码：

import java.io.OutputStream;
import java.util.List;
import javax.servlet.http.HttpServletResponse;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRichTextString;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import com.forenms.exam.domain.ExamInfo;
public class ObjectToExcellUtil {
  //导出的文件名称
  public static String FILE_NAME = "examInfo";
  public static String[] CELLS = {"序号","编号","真实姓名","证件类型","证件号","性别","出生年月","科目","准考证号","座位号","考场号","开考时间","结束时间"};
  //examId,realName,身份证,user_card,sex,没有字段,assessment_project,admission_number,seat_number
  public static void examInfoToExcel(List<ExamInfo> xls,int CountColumnNum,String filename,String[] names,HttpServletResponse response) throws Exception {
      // 获取总列数
//     int CountColumnNum = CountColumnNum;
      // 创建Excel文档
      HSSFWorkbook hwb = new HSSFWorkbook();
      ExamInfo xlsDto = null;
      // sheet 对应一个工作页
      HSSFSheet sheet = hwb.createSheet(filename);
//     sheet.setColumnHidden(1,true);//隐藏列
      HSSFRow firstrow = sheet.createRow(0); // 下标为0的行开始
      HSSFCell[] firstcell = new HSSFCell[names.length];
      for (int j = 0; j < names.length; j++) {
         sheet.setColumnWidth(j, 5000);
        firstcell[j] = firstrow.createCell(j);
        firstcell[j].setCellValue(new HSSFRichTextString(names[j]));
      }
      for (int i = 0; i < CountColumnNum; i++) {
        // 创建一行
        HSSFRow row = sheet.createRow(i + 1);
        // 得到要插入的每一条记录
        xlsDto = xls.get(i);
        for (int colu = 0; colu <= 12; colu++) {
          // 在一行内循环
          HSSFCell xh = row.createCell(0);
          xh.setCellValue(i+1);
          HSSFCell examid = row.createCell(1);
          examid.setCellValue(xlsDto.getExamId());
          HSSFCell realName = row.createCell(2);
          realName.setCellValue(xlsDto.getRealName());
          HSSFCell zjlx = row.createCell(3);
          zjlx.setCellValue("身份证");
          HSSFCell userCard = row.createCell(4);
          userCard.setCellValue(xlsDto.getUserCard());
          HSSFCell sex = row.createCell(5);
          sex.setCellValue(xlsDto.getSex());
          HSSFCell born = row.createCell(6);
          String bornTime = xlsDto.getUserCard().substring(6, 14);
          born.setCellValue(bornTime);
          HSSFCell assessment_project = row.createCell(7);
          assessment_project.setCellValue(xlsDto.getAssessmentProject());
          HSSFCell admission_number = row.createCell(8);
          admission_number.setCellValue(xlsDto.getAdmission_number());
          HSSFCell seat_number = row.createCell(9);
          seat_number.setCellValue(xlsDto.getSeat_number());
          HSSFCell fRoomName = row.createCell(10);
          fRoomName.setCellValue(xlsDto.getfRoomName());
          HSSFCell fBeginTime = row.createCell(11);
          fBeginTime.setCellValue(xlsDto.getfBeginTime());
          HSSFCell fEndTime = row.createCell(12);
          fEndTime.setCellValue(xlsDto.getfEndTime());
        }
      }
      // 创建文件输出流，准备输出电子表格
      response.reset();
      response.setContentType("application/vnd.ms-excel;charset=GBK");
      response.addHeader("Content-Disposition", "attachment;filename="+filename+".xls");
      OutputStream os = response.getOutputStream(); 
      hwb.write(os);
      os.close();
    }
}

导出的功能十分简单，只要封装好对象，直接调用方法即可，现在讲讲导入的时候前台页面怎么调用问题，

<form method="post" action="adminLogin/auditResults/import" enctype="multipart/form-data" onsubmit="return importData();"> 
<input id="filepath" name="insuranceExcelFile" type="file" size="30" value=""   />
<button type="submit"  value="导入数据">导入数据</button>

导入的前台表单提交的时候，要注意设置 enctype=”multipart/form-data” ，其他也没什么难度。
后台接受的controller：

/**
* 读取用户提供的examinfo.xls
* @param request
* @param response
* @param session
* @return
* @throws Exception
*/
@RequestMapping(value="adminLogin/auditResults/import",method=RequestMethod.POST)
public ModelAndView importExamInfoExcell(HttpServletRequest request,HttpServletResponse response, HttpSession session)throws Exception{
    //获取请求封装
    MultipartHttpServletRequest multipartRequest=(MultipartHttpServletRequest)request;
    Map<String, MultipartFile> fileMap = multipartRequest.getFileMap();
    //读取需要填写准考证号的人员名单
    ExamInfo examInfo = new ExamInfo();
    List<ExamInfo> info = examInfoService.queryExamInfoForDownLoad(examInfo);
    //获取请求封装对象
    for(Entry<String, MultipartFile> entry: fileMap.entrySet()){
      MultipartFile multipartFile = entry.getValue();
      InputStream inputStream = multipartFile.getInputStream();
      POIFSFileSystem poifsFileSystem = new POIFSFileSystem(inputStream);
      //从xml读取需要的数据
      List<ExamInfo> list = ExcellToObjectUtil.readXlsForJS(poifsFileSystem);
      for (ExamInfo ei : list) {
         //通过匹配身份证号 填写对应的数据
        for (ExamInfo in : info){
          //如果身份证号 相同 则录入数据
if(in.getUserCard().trim().toUpperCase().equals(ei.getUserCard().trim().toUpperCase())){
            ei.setExamId(in.getExamId());
            examInfoService.updateExamInfoById(ei);
            break;
          }
        }
      }
    }
    ModelAndView mav=new ModelAndView(PATH+"importExcelTip");
    request.setAttribute("data", "ok");
    return mav;
}

以上就是Java项目中如何将Excel文件从数据库导入与导出，小编相信有部分知识点可能是我们日常工作会见到或用到的。希望你能通过这篇文章学到更多知识。更多详情敬请关注亿速云行业资讯频道。

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Java项目中如何将Excel文件从数据库导入与导出

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