List集合转换成Excel格式 ; Excel格式转换成List集合

List集合转换成Excel格式:
package importandexport;

import java.io.FileOutputStream;
import java.util.List;

import javax.annotation.Resource;

import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import check.entity.User;
import check.service.UserService;

public class WriteListToExcelFile {

private ApplicationContext ac ;@Resource(name = "userService")private UserService service;public static void writeListToFile(String fileName, List<User> userList) throws Exception{    HSSFWorkbook workbook = new HSSFWorkbook();    HSSFSheet sheet = workbook.createSheet("用户信息");    HSSFRow head = sheet.createRow(0);    head.createCell(0).setCellValue("account");    head.createCell(1).setCellValue("password");    if(userList!=null&&userList.size()>0) {        for (User user : userList) {            HSSFRow body = sheet.createRow(sheet.getLastRowNum()+1);            body.createCell(0).setCellValue(user.getAccount());            body.createCell(1).setCellValue(user.getPassword());        }        FileOutputStream fos = new FileOutputStream(fileName);         workbook.write(fos);         fos.close();     }    System.out.println("导出成功!");} @Testpublic void test() throws Exception{    String[] config = {"config/spring-mvc.xml", "config/spring-mybatis.xml"};    ac= new ClassPathXmlApplicationContext(config);    UserService service = ac.getBean("userService", UserService.class);    List<User> list = service.findAll().getData();    System.out.println(list);    WriteListToExcelFile.writeListToFile("import.xls", list); }

}

Excel格式转换成List集合:
package importandexport;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

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;

import check.entity.User;
import check.util.Util;

public class ReadExcelFileToList {

public static List<User> readExcelData(String fileName) {     List<User> userList = new ArrayList<User>();     try {         FileInputStream fis = new FileInputStream(fileName);         Workbook workbook = null;         if(fileName.toLowerCase().endsWith("xlsx")){             workbook = new XSSFWorkbook(fis);         }else if(fileName.toLowerCase().endsWith("xls")){             workbook = new HSSFWorkbook(fis);         }         int numberOfSheets = workbook.getNumberOfSheets();         for(int i=0; i < numberOfSheets; i++){             Sheet sheet = workbook.getSheetAt(i);             Iterator<Row> rowIterator = sheet.iterator();             while (rowIterator.hasNext())               {                 String account = "";                String password = "";                Row row = rowIterator.next();                 Iterator<Cell> cellIterator = row.cellIterator();                 while (cellIterator.hasNext())                   {                     Cell cell = cellIterator.next();                     switch(cell.getCellType()){                     case Cell.CELL_TYPE_STRING:                         if(account.equalsIgnoreCase("")){                             account = cell.getStringCellValue().trim();                         } else if(password.equalsIgnoreCase("")) {                            password = cell.getStringCellValue().trim();                        } else{                             System.out.println("Random data::"+cell.getStringCellValue());                         }                         break;                     case Cell.CELL_TYPE_NUMERIC:                         System.out.println("Random data::"+cell.getNumericCellValue());                     }                 }                if(!"account".equals(account)) {                    User user = new User();                     user.setId(Util.createId());                    user.setAccount(account);                    user.setPassword(password);                    userList.add(user);                }            }           }         fis.close();     } catch (IOException e) {         e.printStackTrace();     }     return userList; } public static void main(String args[]){     List<User> list = readExcelData("import.xls");     System.out.println(list); } 

}