【poi】用POI新建一个xlsx文件【或者说将数据存入到xlsx中】/【将数据从xlsx中获取到项目中】

 1 package com.it.poiTest;
 2 
 3 import java.io.FileNotFoundException;
 4 import java.io.FileOutputStream;
 5 import java.io.IOException;
 6 import java.util.ArrayList;
 7 import java.util.HashMap;
 8 import java.util.LinkedHashMap;
 9 import java.util.List;
10 import java.util.Map;
11 
12 import org.apache.poi.ss.usermodel.Cell;
13 import org.apache.poi.ss.usermodel.Row;
14 import org.apache.poi.ss.usermodel.Sheet;
15 import org.apache.poi.xssf.usermodel.XSSFRow;
16 import org.apache.poi.xssf.usermodel.XSSFWorkbook;
17 
18 public class CreateWorkBook {
19     @SuppressWarnings("unchecked")
20     public static void main(String[] args) {
21         //1.xlsx文件对象---可以表示xls和xlsx格式文件的类
22         XSSFWorkbook  workbook = new XSSFWorkbook();
23         try {
24             //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
25             Sheet sheet = workbook.createSheet("first sheet");
26             /**
27              * 3.这一截，封装数据
28              */
29             List<Object[]> list = new ArrayList<Object[]>();
30             list.add(new Object[]{"empId","empName","empAge"});
31             list.add(new Object[]{"01","小明","18"});
32             list.add(new Object[]{"02","小犟","12"});
33             list.add(new Object[]{"03","小够","19"});
34             list.add(new Object[]{"04","小离","20"});
35             list.add(new Object[]{"05","小张","30"});
36             
37             //4.行对象---声明行
38             Row row;
39             for(int i=0; i<list.size();i++){
40                 row = sheet.createRow(i);
41                 //5.列对象【单元格对象】---声明列
42                 Object[] obj = list.get(i);
43                 Cell cell = null;
44                 for (int j = 0; j < obj.length; j++) {
45                     cell = row.createCell(j);
46                     cell.setCellValue(obj[j].toString());
47                 }
48             }
49             
50             //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
51             FileOutputStream out = new FileOutputStream("createWorkBook.xlsx");
52             //7.将此xlsx文件以流的形式写出
53             workbook.write(out);
54             //8.关闭流
55             out.close();
56             System.out.println("createWorkBook success");
57         } catch (FileNotFoundException e) {
58             e.printStackTrace();
59         } catch (IOException e) {
60             e.printStackTrace();
61         }
62         
63         
64     }
65 }

 1 package com.it.poiTest;
 2 
 3 import java.io.File;
 4 import java.io.FileInputStream;
 5 import java.io.FileNotFoundException;
 6 import java.io.IOException;
 7 import java.util.ArrayList;
 8 import java.util.Iterator;
 9 import java.util.List;
10 
11 import org.apache.poi.ss.usermodel.Cell;
12 import org.apache.poi.ss.usermodel.Row;
13 import org.apache.poi.ss.usermodel.Sheet;
14 import org.apache.poi.xssf.usermodel.XSSFWorkbook;
15 
16 public class GetWorkBook {
17 
18     public static <E> void main(String[] args) {
19         //1。前三步获取xlsx文件对象
20         File file = new File("createWorkBook.xlsx");
21         try {
22             //2.
23             FileInputStream in = new FileInputStream(file);
24             //3。
25             XSSFWorkbook workbook = new XSSFWorkbook(in);
26             //4.获取工作簿对象
27             Sheet sheet = workbook.getSheetAt(0);
28             //Sheet sheet1 = workbook.getSheet("first sheet");   效果一样
29             //5.迭代取出数据
30             Iterator<Row> rowItera = sheet.iterator();
31             List<Object[]> list =(List<Object[]>) new ArrayList<E>();
32             Row row;
33             while(rowItera.hasNext()){
34                 row = rowItera.next();
35                 Iterator<Cell> cellItera = row.cellIterator();
36                 Cell cell;
37                 while(cellItera.hasNext()){
38                     cell = cellItera.next();
39                     //6.打印
40                     System.out.print(cell.getStringCellValue() + "   ");
41                 }
42                 System.out.println("\n");
43             }
44             
45         } catch (FileNotFoundException e) {
46             e.printStackTrace();
47         } catch (IOException e) {
48             e.printStackTrace();
49         }
50     }
51 
52 }