Java使用POI 导入导出Excel
一、使用的jar依赖版本
<dependency>
<groupId>org.apache.poigroupId>
<artifactId>poi-ooxmlartifactId>
<version>3.17version>
dependency>
注：jar包poi与poi-ooxml的区别：
poi：使用前缀为HSSF的类（HSSFWorkbook），只支持2007以前的excel（文件扩展名为xls）。
poi-ooxml：使用前缀为XSSH的类（XSSFWorkbook），支持2007以前和以后的excel（文件扩展名为xlsx）。
依赖和版本的差异可能会导致代码的差异。
以下代码只支持2007以前和以后的excel（文件扩展名为xlsx。
二、工具类
package test.poi;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import org.apache.poi.ss.usermodel.VerticalAlignment;
import org.apache.poi.ss.usermodel.BorderStyle;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFFont;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
/**
* Excel工具类
*/
public class ExcelUtil {
/**
* 通过模板导出excel文件
* 只支持 xlsx格式
* 只支持 读取excle第一个sheet
* 模板文件默认读取templates/
* @param dataList 数据集合
* @param dataEntityClass 数据实体类
* @param templateName 模板名称
* @param titleRowNum 固定标题行数
* @return
* @throws Exception
*/
public static <T> ByteArrayOutputStream exportExcel(List<T> dataList, Class<T> dataEntityClass, String templateName, int titleRowNum) throws Exception {
if (dataList == null || dataList.size() == 0) {
throw new Exception("数据为空");
}
XSSFWorkbook workbook = null;
try {
// 读取excel模板文件
InputStream in = ExcelUtil.class.getClassLoader().getResourceAsStream("templates/"+templateName);
workbook = new XSSFWorkbook(in);
XSSFSheet sheet = workbook.getSheetAt(0);
// 设置默认行高
//sheet.setDefaultRowHeightInPoints(25F);
// 获取数据实体类的所有字段
Field[] declaredFields = dataEntityClass.getDeclaredFields();
int declaredFieldsSize = declaredFields.length;
// ByteArray输出字节流
ByteArrayOutputStream baos = new ByteArrayOutputStream();
// 遍历数据写入到excel
int dataListSize = dataList.size();
for (int i = 0; i < dataListSize; i++) {
// 获取数据list里面的对象实例
T instance = dataList.get(i);
// 创建行
Row row = sheet.createRow(i + titleRowNum);
for(int j = 0; j < declaredFieldsSize; j++){
Field field = declaredFields[j];
field.setAccessible(true);
// 获取字段的值
Object value = field.get(instance);
// 创建单元格
Cell cell = row.createCell(j);
// 设置单元格样式
XSSFCellStyle cellStyle = workbook.createCellStyle();
// 设置文本对齐方式
cellStyle.setWrapText(true); //设置自动换行
cellStyle.setAlignment(HorizontalAlignment.CENTER);// 水平居中
cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);// 垂直居中
// 设置边框
cellStyle.setBorderBottom(BorderStyle.THIN); // 下边框
cellStyle.setBorderLeft(BorderStyle.THIN);// 左边框
cellStyle.setBorderTop(BorderStyle.THIN);// 上边框
cellStyle.setBorderRight(BorderStyle.THIN);// 右边框
// 设置字体
XSSFFont font = workbook.createFont();
font.setFontName("宋体");// 设置字体名称
font.setFontHeightInPoints((short) 11);// 设置字号
font.setColor(IndexedColors.BLACK.index);// 设置字体颜色
cellStyle.setFont(font);
cell.setCellStyle(cellStyle);
cell.setCellValue(value != null ? value.toString() : "");
}
}
workbook.write(baos);
return baos;
} finally {
try {
if (workbook != null) {
workbook.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 读取excle
* 只支持 xlsx格式
* 只支持 读取excle第一个sheet
* @param excelFile excle文件
* @param dataEntityClass 数据实体类
* @param titleRowNum 固定标题行数
* @return
* @throws Exception
*/
public static <T> List<T> importExcel(File excelFile, Class<T> dataEntityClass, int titleRowNum) throws Exception {
if (excelFile == null) {
throw new Exception("参数excle文件(excelFile)不能为空");
}
XSSFWorkbook workBook = null;
List<T> result = new ArrayList<T>();
DecimalFormat df = new DecimalFormat("0"); // 格式化number String字符
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); // 日期格式化
try {
// 通过excle文件构建XSSFWorkbook对象
workBook = new XSSFWorkbook(excelFile);
// 获取excle第一个sheet
XSSFSheet sheet = workBook.getSheetAt(0);
// sheet.getFirstRowNum() 获取所有有数据的第一行索引，从0开始
// sheet.getLastRowNum() 获取所有有数据的最后一行索引，从0开始
for(int i = sheet.getFirstRowNum() + titleRowNum ; i <= sheet.getLastRowNum(); i++) {
Row row = sheet.getRow(i);
if (row == null) {
continue;
}
T object = dataEntityClass.newInstance();
Field[] fields = object.getClass().getDeclaredFields();
Field.setAccessible(fields, true);
// row.getFirstCellNum() 获取一行中有数据的列的第一列索引，从0开始
// row.getLastCellNum() 获取一行中有数据的列的最后一列索引，从0开始
for(int j = row.getFirstCellNum(); j < row.getLastCellNum(); j++) {
Cell cell = row.getCell(j);
if (cell == null) {
continue;
}
Object value = null;
if (cell.getCellTypeEnum() == CellType.STRING) {
value = cell.getStringCellValue();
} else if (cell.getCellTypeEnum() == CellType.NUMERIC) {
if ("General".equals(cell.getCellStyle().getDataFormatString())) {
value = cell.getNumericCellValue();
} else if ("m/d/yy".equals(cell.getCellStyle().getDataFormatString())) {
value = sdf.format(cell.getDateCellValue());
} else {
value = df.format(cell.getNumericCellValue());
}
} else if (cell.getCellTypeEnum() == CellType.BOOLEAN) {
value = cell.getBooleanCellValue();
} else if (cell.getCellTypeEnum() == CellType.BLANK) {
value = "";
} else {
value = "";
}
Field field = fields[j];
Object vObj = null;
String vStr = value.toString();
if (field.getType() == String.class) {
vObj = vStr;
} else if (field.getType() == Integer.class) {
vObj = Integer.valueOf(df.format(value));
} else if (field.getType() == Double.class) {
vObj = Double.valueOf(vStr);
} else if (field.getType() == Long.class) {
vObj = Long.valueOf(df.format(value));
} else if (field.getType() == Boolean.class) {
vObj = Boolean.valueOf(vStr);
} else {
vObj = value;
}
field.set(object, vObj);
}
result.add(object);
Field.setAccessible(fields, false);
}
} finally {
try {
if (workBook != null) {
workBook.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}
}
三、控制类
package test.controller;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import test.domain.ExcelDataTest;
import test.poi.ExcelUtil;
import test.util.DownloadUtil;
import test.util.FileUtil;
@RestController
@RequestMapping("/excel")
public class ExcelController {
/**
* 导出Excel数据
* @param response
* @throws Exception
*/
@RequestMapping(value = "/export" , method = RequestMethod.GET, produces = "application/json")
public void export(HttpServletResponse response) throws Exception{
ByteArrayOutputStream baos = null;
OutputStream out = null;
try {
// excel数据 实际运用从数据库中查询
List<ExcelDataTest> dataList = new ArrayList<ExcelDataTest>();
ExcelDataTest data = new ExcelDataTest();
data.setColumn1(123456);
data.setColumn2("测试测试");
data.setColumn3("测试测试测试测测试测试测试");
dataList.add(data);
baos = ExcelUtil.exportExcel(dataList, ExcelDataTest.class, "excel测试模板.xlsx", 2);
DownloadUtil.generalDownload(response, baos, "excle导出测试.xlsx");
} catch (Exception e) {
e.printStackTrace();
throw new Exception("导出失败：" + e.getMessage());
} finally {
if(baos != null){
baos.close();
}
if(out != null){
out.close();
}
}
}
/**
* 导入Excel数据
* @param file
*/
@RequestMapping(value = "/import", method = RequestMethod.POST)
public void importExcel(MultipartFile file) {
File f = null;
try {
// MultipartFile 转 file
f = FileUtil.multipartFileToFile(file);
List<ExcelDataTest> list = ExcelUtil.importExcel(f, ExcelDataTest.class, 2);
for (ExcelDataTest data : list) {
// 实际这里是保存数据库操作
System.out.println(data.toString());
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (f != null) {
f.delete();
}
}
}
}
下载工具类 DownloadUtil
package test.util;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.URLEncoder;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
/**
* 下载工具类
*/
public class DownloadUtil {
/**
* 通用下载设置
* @param response
* @param outData 输出数据 ByteArrayOutputStream
* @param fileName 文件名
* @throws Exception
*/
public static void generalDownload(HttpServletResponse response, ByteArrayOutputStream outData, String fileName) throws Exception{
response.setContentType( "application/x-msdownload");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
ServletOutputStream out = response.getOutputStream();
outData.writeTo(out);
out.flush();
out.close();
}
/**
* 通用下载设置
* @param response
* @param outData 输出数据 InputStream
* @param fileName 文件名
* @throws Exception
*/
public static void generalDownload(HttpServletResponse response, InputStream outData, String fileName) throws Exception{
response.setContentType( "application/x-msdownload");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
ServletOutputStream out = response.getOutputStream();
byte[] bffer = new byte[1024];
int r = outData.read(bffer, 0, 1024);
while (r != -1) {
out.write(bffer);
r = outData.read(bffer, 0, 1024);
}
out.flush();
out.close();
}
/**
* 通用下载设置
* @param response
* @param outData 输出数据 byte[]
* @param fileName 文件名
* @throws Exception
*/
public static void generalDownload(HttpServletResponse response, byte[] outData, String fileName) throws Exception{
response.setContentType( "application/x-msdownload");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
ServletOutputStream out = response.getOutputStream();
out.write(outData);
out.flush();
out.close();
}
}
文件工具类 FileUtil
package test.util;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import org.springframework.web.multipart.MultipartFile;
/**
* 文件工具类
*/
public class FileUtil {
/**
* MultipartFile 转 File
* @param file
* 注意：转换的文件保存在项目的根目录，因此使用完要及时清理
* @throws Exception
*/
public static File multipartFileToFile(MultipartFile multipartFile) throws Exception {
File toFile = null;
if (multipartFile != null) {
InputStream in = multipartFile.getInputStream();
toFile = new File(multipartFile.getOriginalFilename());
OutputStream os = new FileOutputStream(toFile);
int r = 0;
byte[] buffer = new byte[1024];
while ((r = in.read(buffer, 0, 1024)) != -1) {
os.write(buffer, 0, r);
}
try {
if (os != null) {
os.close();
}
} catch (Exception e) {
}
try {
if (in != null) {
in.close();
}
} catch (Exception e) {
}
}
return toFile;
}
}
数据实体类 ExcelDataTest
package test.domain;
public class ExcelDataTest {
private Integer column1;
private String column2;
private String column3;
@Override
public String toString() {
return "ExcelDataTest [column1=" + column1 + ", column2=" + column2 + ", column3=" + column3 + "]";
}
public Integer getColumn1() {
return column1;
}
public void setColumn1(Integer column1) {
this.column1 = column1;
}
public String getColumn2() {
return column2;
}
public void setColumn2(String column2) {
this.column2 = column2;
}
public String getColumn3() {
return column3;
}
public void setColumn3(String column3) {
this.column3 = column3;
}
}
模板文件
（存放路径为src/main/resources/templates）
四、运行结果
导出
导入
Excel数据
结果
