第一部分：写入xlsx中
使用POI创建一个xlsx文件：
项目结构如下：
具体使用的POI中的
XSSFWorkbook xlsx对象
Sheet 工作簿对象
Row 行对象
Cell 单元格对象
FileOutputStream 流对象
代码如下：
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();
} }
}
第二部分：从xlsx文件中读取到项目中
代码如下：
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();
}
} }