ExcelUtil工具类(XSSFWorkbook读取和写入Excel)，入参和出参都是：List<Map<String,Object>>
一、读取Excel
testdata.xlsx
1、new XSSFWorkbook对象
File file = new File(filePath);
FileInputStream fis = new FileInputStream(file);
XSSFWorkbook wb = new XSSFWorkbook(fis);
2、new XSSFSheet对象
//获取sheet第一个
XSSFSheet xSheet = wb.getSheetAt(0);
if(sheetName!=null) {
//如果sheetName入参可用这个,通过名称获取
xSheet = wb.getSheet(sheetName);
}
3、遍历行读取数据写入List<Map<String,Object>>
for (int i = 0; i <= xSheet.getLastRowNum(); i++) { //遍历所有行
if(i==0){ //标题行
for (int j = 0; j < xSheet.getRow(i).getPhysicalNumberOfCells(); j++) {
headMap.put(j, xSheet.getRow(i).getCell(j).toString());
}
continue;
}
Map<String, Object> paramsMap = new HashMap<>();
for (int j = 0; j < xSheet.getRow(i).getPhysicalNumberOfCells(); j++) { //遍历当前行所有列
String key=headMap.get(j);
Cell cell=xSheet.getRow(i).getCell(j);
switch (cell.getCellType()) {
case Cell.CELL_TYPE_STRING:
paramsMap.put(key,cell.getStringCellValue());
break;
case Cell.CELL_TYPE_NUMERIC:
paramsMap.put(key,new Double(cell.getNumericCellValue()).intValue());
break;
}
//paramsMap.put(key,xSheet.getRow(i).getCell(j));
}
resultList.add(paramsMap);
}
二、写入Excel
1、XSSFWorkbook 创建一个工作蒲
XSSFWorkbook xwb = new XSSFWorkbook();
XSSFSheet sheet = xwb.createSheet(sheetName);
2、XSSFSheet写入标题行
XSSFRow row = sheet.createRow(0);
for (int i=0;i<listHead.size();i++){
//根据需要给第一行每一列设置标题
XSSFCell cell = row.createCell(i);
cell.setCellValue(listHead.get(i));
}
3、数据赋值并设置列
//创建行
XSSFRow rows;
//创建列，即单元格Cell
XSSFCell cells;//把List里面的数据写到excel中(除标题行外)
for (int i=0;i<listA.size();i++) {
//从第一行开始写入
rows = sheet.createRow(i + 1);
//创建每个单元格Cell，即列的数据
Map<String, Object> testMap =listA.get(i);
for (int j=0;j<listHead.size();j++){
cells = rows.createCell(j);
String head=listHead.get(j);
String type=testMap.get(head).getClass().getTypeName();
switch (type) {
case "java.lang.Integer":
cells.setCellValue((int) testMap.get(head));
break;
case "java.lang.String":
cells.setCellValue((String) testMap.get(head));
break;
}
}
}
4、写入excel
File file = new File(filePath);
FileOutputStream outputStream = new FileOutputStream(file);
xwb.write(outputStream);
outputStream.flush();
outputStream.close();
result.xlsx
三、整体工具类(参考)
package com.example.utils;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.*;
/**
* Description :
*
* @author : HMF
* Date : Created in 10:40 2023/11/23
* @version :
*/
public class ExcelUtil {
/**
* 读取excel,放入List<Map<String, String>>
* @param filePath 读取excel的文件路径+文件名称
* @return datalist
*/
public static List<Map<String,Object>> readExcel(String filePath){
return readExcel(filePath,null);
}
/**
* 读取excel,放入List<Map<String, String>>
* @param filePath 读取excel的文件路径+文件名称
* @Param sheetName sheet名称
* @return datalist
*/
public static List<Map<String,Object>> readExcel(String filePath,String sheetName){
List<Map<String,Object>> resultList = new ArrayList<>();
Map<Integer, String> headMap = new HashMap<>();
try {
File file = new File(filePath);
FileInputStream fis = new FileInputStream(file);
XSSFWorkbook wb = new XSSFWorkbook(fis);
//获取sheet第一个
XSSFSheet xSheet = wb.getSheetAt(0);
if(sheetName!=null) {
//如果sheetName入参可用这个,通过名称获取
xSheet = wb.getSheet(sheetName);
}
for (int i = 0; i <= xSheet.getLastRowNum(); i++) { //遍历所有行
if(i==0){ //标题行
for (int j = 0; j < xSheet.getRow(i).getPhysicalNumberOfCells(); j++) {
headMap.put(j, xSheet.getRow(i).getCell(j).toString());
}
continue;
}
Map<String, Object> paramsMap = new HashMap<>();
for (int j = 0; j < xSheet.getRow(i).getPhysicalNumberOfCells(); j++) { //遍历当前行所有列
String key=headMap.get(j);
Cell cell=xSheet.getRow(i).getCell(j);
switch (cell.getCellType()) {
case Cell.CELL_TYPE_STRING:
paramsMap.put(key,cell.getStringCellValue());
break;
case Cell.CELL_TYPE_NUMERIC:
paramsMap.put(key,new Double(cell.getNumericCellValue()).intValue());
break;
}
//paramsMap.put(key,xSheet.getRow(i).getCell(j));
}
resultList.add(paramsMap);
}
}catch (IOException e){
System.out.println(e);
}
return resultList;
}
/**
* 写入excel
* @param filePath 读取excel的文件路径+文件名称
* @Param sheetName sheet名称
* @param listA 入参列表
* @param listHead 标题头列表
*/
public static void writeExcel(String filePath, String sheetName, List<Map<String, Object>> listA,List<String> listHead){
XSSFWorkbook xwb = new XSSFWorkbook();
XSSFSheet sheet = xwb.createSheet(sheetName);
//标题行
XSSFRow row = sheet.createRow(0);
for (int i=0;i<listHead.size();i++){
//根据需要给第一行每一列设置标题
XSSFCell cell = row.createCell(i);
cell.setCellValue(listHead.get(i));
}
//创建行
XSSFRow rows;
//创建列，即单元格Cell
XSSFCell cells;
//把List里面的数据写到excel中(除标题行外)
for (int i=0;i<listA.size();i++) {
//从第一行开始写入
rows = sheet.createRow(i + 1);
//创建每个单元格Cell，即列的数据
Map<String, Object> testMap =listA.get(i);
for (int j=0;j<listHead.size();j++){
cells = rows.createCell(j);
String head=listHead.get(j);
String type=testMap.get(head).getClass().getTypeName();
switch (type) {
case "java.lang.Integer":
cells.setCellValue((int) testMap.get(head));
break;
case "java.lang.String":
cells.setCellValue((String) testMap.get(head));
break;
}
}
}
//用输出流写到excel
try {
File file = new File(filePath);
FileOutputStream outputStream = new FileOutputStream(file);
xwb.write(outputStream);
outputStream.flush();
outputStream.close();
}catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String args[]){
String filePath="src/main/resources/testdata.xlsx";
List<Map<String, Object>> resultList= readExcel(filePath,"Sheet1");
for(Map<String, Object> testMap:resultList){
System.out.println(testMap);
// for(String excKey :testMap.keySet()){
// System.out.println(excKey+": "+testMap.get(excKey));
// }
}
List<String> listHead =new ArrayList<>();
listHead.add("id");
listHead.add("name");
listHead.add("age");
listHead.add("grade");
writeExcel("src/main/resources/result.xlsx","result",resultList,listHead);
}
}
参考：https://www.cnblogs.com/janson071/p/10119935.html
