java 对excel的导入及导出
最近在做对excel的导入导出,在平常的工作中,导入导出excel数据是常见的需求,今天就简单的记录一下Java是如何来实现这个功能的,感兴趣或者正好大家在工作中遇到了可以了解下。
首先我们能引入导入导出所需要用到Maven依赖,因为返回用到了阿里巴巴的Json包所也引入fastjson包及文件上传的包
<!-- POI -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>5.2.0</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>5.2.0</version>
</dependency>
<!-- JSON -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.83</version>
</dependency>
<!-- 文件上传 -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpmime</artifactId>
<version>4.5.13</version>
</dependency>
<!--HTTP-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
<scope>provided</scope>
</dependency>
<!-- springframework -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.3.18</version>
</dependency>
导入Controller层
@ResponseBody
@RequestMapping(value="import")
public JSONArray import(@RequestPart("file")MultipartFile file) throws Exception{
JSONArray array = ExcelUtil.readMultipartFile(file);
System.out.println("导入数据为:" + array);
return array;
}
然后导入解析为对象(基础)创建需要的一个与导入表格对应的Java实体对象
ExcelUtils(导入导出工具类)
package com./*自己包名路径*/.utils;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.web.multipart.MultipartFile;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.text.NumberFormat;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
public class ExcelUtil {
private static final String XLSX = ".xlsx";
private static final String XLS = ".xls";
private static final String ROW_NUM = "rowNum";
private static final NumberFormat NUMBER_FORMAT = NumberFormat.getNumberInstance();
public static JSONArray readFile(File file) throws Exception {
return readExcel(null, file);
}
private static JSONArray readExcel(MultipartFile mFile, File file) throws IOException {
boolean fileNotExist = (file == null || !file.exists());
if (mFile == null && fileNotExist) {
return new JSONArray();
}
// 解析表格数据
InputStream in;
String fileName;
if (mFile != null) {
// 上传文件解析
in = mFile.getInputStream();
fileName = getString(mFile.getOriginalFilename()).toLowerCase();
} else {
// 本地文件解析
in = new FileInputStream(file);
fileName = file.getName().toLowerCase();
}
Workbook book;
if (fileName.endsWith(XLSX)) {
book = new XSSFWorkbook(in);
} else if (fileName.endsWith(XLS)) {
POIFSFileSystem poifsFileSystem = new POIFSFileSystem(in);
book = new HSSFWorkbook(poifsFileSystem);
} else {
return new JSONArray();
}
JSONArray array = read(book);
book.close();
in.close();
return array;
}
private static String getString(String s) {
if (s == null) {
return "";
}
if (s.isEmpty()) {
return s;
}
return s.trim();
}
private static JSONArray read(Workbook book) {
// 获取 Excel 文件第一个 Sheet 页面
Sheet sheet = book.getSheetAt(0);
return readSheet(sheet);
}
private static JSONArray readSheet(Sheet sheet) {
// 首行下标
int rowStart = sheet.getFirstRowNum();
// 尾行下标
int rowEnd = sheet.getLastRowNum();
// 获取表头行
Row headRow = sheet.getRow(rowStart);
if (headRow == null) {
return new JSONArray();
}
int cellStart = headRow.getFirstCellNum();
int cellEnd = headRow.getLastCellNum();
Map<Integer, String> keyMap = new HashMap<>();
for (int j = cellStart; j < cellEnd; j++) {
// 获取表头数据
String val = getCellValue(headRow.getCell(j));
if (val != null && val.trim().length() != 0) {
keyMap.put(j, val);
}
}
// 如果表头没有数据则不进行解析
if (keyMap.isEmpty()) {
return (JSONArray) Collections.emptyList();
}
// 获取每行JSON对象的值
JSONArray array = new JSONArray();
// 如果首行与尾行相同,表明只有一行,返回表头数据
if (rowStart == rowEnd) {
JSONObject obj = new JSONObject();
// 添加行号
obj.put(ROW_NUM, 1);
for (int i : keyMap.keySet()) {
obj.put(keyMap.get(i), "");
}
array.add(obj);
return array;
}
for (int i = rowStart + 1; i <= rowEnd; i++) {
Row eachRow = sheet.getRow(i);
JSONObject obj = new JSONObject();
// 添加行号
obj.put(ROW_NUM, i + 1);
StringBuilder sb = new StringBuilder();
for (int k = cellStart; k < cellEnd; k++) {
if (eachRow != null) {
String val = getCellValue(eachRow.getCell(k));
// 所有数据添加到里面,用于判断该行是否为空
sb.append(val);
obj.put(keyMap.get(k), val);
}
}
if (sb.length() > 0) {
array.add(obj);
}
}
return array;
}
private static String getCellValue(Cell cell) {
// 空白或空
if (cell == null || cell.getCellTypeEnum() == CellType.BLANK) {
return "";
}
// String类型
if (cell.getCellTypeEnum() == CellType.STRING) {
String val = cell.getStringCellValue();
if (val == null || val.trim().length() == 0) {
return "";
}
return val.trim();
}
// 数字类型
if (cell.getCellTypeEnum() == CellType.NUMERIC) {
// 科学计数法类型
return NUMBER_FORMAT.format(cell.getNumericCellValue()) + "";
}
// 布尔值类型
if (cell.getCellTypeEnum() == CellType.BOOLEAN) {
return cell.getBooleanCellValue() + "";
}
// 错误类型
return cell.getCellFormula();
}
private static void export(HttpServletResponse response, File file, String fileName, String sheetName, List<List<Object>> sheetDataList, Map<Integer, List<String>> selectMap) {
// 整个 Excel 表格 book 对象
SXSSFWorkbook book = new SXSSFWorkbook();
// 每个 Sheet 页
Sheet sheet = book.createSheet(sheetName);
Drawing<?> patriarch = sheet.createDrawingPatriarch();
// 设置表头背景色(灰色)
CellStyle headStyle = book.createCellStyle();
headStyle.setFillForegroundColor(IndexedColors.GREY_80_PERCENT.index);
headStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
headStyle.setAlignment(HorizontalAlignment.CENTER);
headStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.index);
// 设置表身背景色(默认色)
CellStyle rowStyle = book.createCellStyle();
rowStyle.setAlignment(HorizontalAlignment.CENTER);
rowStyle.setVerticalAlignment(VerticalAlignment.CENTER);
// 设置表格列宽度(默认为15个字节)
sheet.setDefaultColumnWidth(15);
// 创建合并算法数组
int rowLength = sheetDataList.size();
int columnLength = sheetDataList.get(0).size();
int[][] mergeArray = new int[rowLength][columnLength];
for (int i = 0; i < sheetDataList.size(); i++) {
// 每个 Sheet 页中的行数据
Row row = sheet.createRow(i);
List<Object> rowList = sheetDataList.get(i);
for (int j = 0; j < rowList.size(); j++) {
// 每个行数据中的单元格数据
Object o = rowList.get(j);
int v = 0;
if (o instanceof URL) {
// 如果要导出图片的话, 链接需要传递 URL 对象
setCellPicture(book, row, patriarch, i, j, (URL) o);
} else {
Cell cell = row.createCell(j);
if (i == 0) {
// 第一行为表头行,采用灰色底背景
v = setCellValue(cell, o, headStyle);
} else {
// 其他行为数据行,默认白底色
v = setCellValue(cell, o, rowStyle);
}
}
mergeArray[i][j] = v;
}
}
// 合并单元格
mergeCells(sheet, mergeArray);
// 设置下拉列表
setSelect(sheet, selectMap);
// 写数据
if (response != null) {
// 前端导出
try {
write(response, book, fileName);
} catch (IOException e) {
e.printStackTrace();
}
} else {
// 本地导出
FileOutputStream fos;
try {
fos = new FileOutputStream(file);
ByteArrayOutputStream ops = new ByteArrayOutputStream();
book.write(ops);
fos.write(ops.toByteArray());
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
public static void export(HttpServletResponse response, String fileName,List<List<Object>> sheetDataList) {
export(response, fileName, fileName, sheetDataList, null);
}
public static void export(HttpServletResponse response, String fileName, String sheetName, List<List<Object>> sheetDataList, Map<Integer, List<String>> selectMap){
export(response, null, fileName, sheetName, sheetDataList, selectMap);
}
}
动态导出Controller
这种方式十分灵活,表中的数据,完全自定义设置。
@ResponseBody
@RequestMapping(value="export")
public void export(@RequestPart("file")MultipartFile file) throws Exception{
// 表头数据
List<Object> head = Arrays.asList("姓名","年龄","性别");
// 用户1数据
List<Object> user1 = new ArrayList<>();
user1.add("111");
user1.add(60);
user1.add("男");
// 用户2数据
List<Object> user2 = new ArrayList<>();
user2.add("222");
user2.add(28);
user2.add("女");
// 将数据汇总
List<List<Object>> sheetDataList = new ArrayList<>();
sheetDataList.add(head);
sheetDataList.add(user1);
sheetDataList.add(user2);
// 导出数据
ExcelUtil.export(response,"用户表", sheetDataList);
}