package com.it.poiTest;

 import java.io.FileNotFoundException;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.HashMap;

 import java.util.LinkedHashMap;

 import java.util.List;

 import java.util.Map;

 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.xssf.usermodel.XSSFRow;

 import org.apache.poi.xssf.usermodel.XSSFWorkbook;

 public class CreateWorkBook {

     @SuppressWarnings("unchecked")

     public static void main(String[] args) {

         //1.xlsx文件对象---可以表示xls和xlsx格式文件的类

         XSSFWorkbook  workbook = new XSSFWorkbook();

         try {

             //2.工作簿对象---新创建的xls需要新创建新的工作簿，offine默认创建的时候会默认生成三个sheet

             Sheet sheet = workbook.createSheet("first sheet");

             /**

              * 3.这一截，封装数据

              */

             List<Object[]> list = new ArrayList<Object[]>();

             list.add(new Object[]{"empId","empName","empAge"});

             list.add(new Object[]{"01","小明","18"});

             list.add(new Object[]{"02","小犟","12"});

             list.add(new Object[]{"03","小够","19"});

             list.add(new Object[]{"04","小离","20"});

             list.add(new Object[]{"05","小张","30"});

             //4.行对象---声明行

             Row row;

             for(int i=0; i<list.size();i++){

                 row = sheet.createRow(i);

                 //5.列对象【单元格对象】---声明列

                 Object[] obj = list.get(i);

                 Cell cell = null;

                 for (int j = 0; j < obj.length; j++) {

                     cell = row.createCell(j);

                     cell.setCellValue(obj[j].toString());

                 }

             }

             //6.未指定具体路径，则自动创建文件在项目下;若指定具体磁盘路径，也可以

             FileOutputStream out = new FileOutputStream("createWorkBook.xlsx");

             //7.将此xlsx文件以流的形式写出

             workbook.write(out);

             //8.关闭流

             out.close();

             System.out.println("createWorkBook success");

         } catch (FileNotFoundException e) {

             e.printStackTrace();

         } catch (IOException e) {

             e.printStackTrace();

         }

     }

 }

 package com.it.poiTest;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.Iterator;

 import java.util.List;

 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.xssf.usermodel.XSSFWorkbook;

 public class GetWorkBook {

     public static <E> void main(String[] args) {

         //1。前三步获取xlsx文件对象

         File file = new File("createWorkBook.xlsx");

         try {

             //2.

             FileInputStream in = new FileInputStream(file);

             //3。

             XSSFWorkbook workbook = new XSSFWorkbook(in);

             //4.获取工作簿对象

             Sheet sheet = workbook.getSheetAt(0);

             //Sheet sheet1 = workbook.getSheet("first sheet");   效果一样

             //5.迭代取出数据

             Iterator<Row> rowItera = sheet.iterator();

             List<Object[]> list =(List<Object[]>) new ArrayList<E>();

             Row row;

             while(rowItera.hasNext()){

                 row = rowItera.next();

                 Iterator<Cell> cellItera = row.cellIterator();

                 Cell cell;

                 while(cellItera.hasNext()){

                     cell = cellItera.next();

                     //6.打印

                     System.out.print(cell.getStringCellValue() + "   ");

                 }

                 System.out.println("\n");

             }

         } catch (FileNotFoundException e) {

             e.printStackTrace();

         } catch (IOException e) {

             e.printStackTrace();

         }

     }

 }