一、添加poi的maven依赖
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.13</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.13</version>
</dependency>
二、自定义注解(Excel属性标题、位置等)
package com.cloud.core.annotation;
import java.lang.annotation.*;
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ExcelColumn {
String value() default "";
int col() default 0;
}
三、CustomExcelUtils编写
package com.cloud.core.utils;
import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;
import com.cloud.core.annotation.ExcelColumn;
import com.cloud.core.common.CommonConst;
import org.apache.commons.lang.BooleanUtils;
import org.apache.commons.lang.CharUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.math.NumberUtils;
import org.apache.poi.hssf.usermodel.HSSFDateUtil;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.MediaType;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class CustomExcelUtils {
private final static Logger log = LoggerFactory.getLogger(CustomExcelUtils.class);
private final static String EXCEL2003 = "xls";
private final static String EXCEL2007 = "xlsx";
public static <T> List<T> readExcel(String path, Class<T> cls, int startRow, MultipartFile file) {
String fileName = file.getOriginalFilename();
if (!fileName.matches(CommonConst.Regex.FILE_EXT_XLS) && !fileName.matches(CommonConst.Regex.FILE_EXT_XLSX)) {
log.error("上传文件格式不正确");
}
List<T> dataList = new ArrayList<>();
Workbook workbook = null;
try {
InputStream is = file.getInputStream();
if (fileName.endsWith(EXCEL2007)) {
// FileInputStream is = new FileInputStream(new File(path));
workbook = new XSSFWorkbook(is);
}
if (fileName.endsWith(EXCEL2003)) {
// FileInputStream is = new FileInputStream(new File(path));
workbook = new HSSFWorkbook(is);
}
if (workbook != null) {
//类映射 注解 value-->bean columns
Map<String, List<Field>> classMap = new HashMap<>();
List<Field> fields = Stream.of(cls.getDeclaredFields()).collect(Collectors.toList());
fields.forEach(
field -> {
ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
if (annotation != null) {
String value = annotation.value();
if (StringUtils.isBlank(value)) {
// return起到的作用和continue是相同的 语法
return;
}
if (!classMap.containsKey(value)) {
classMap.put(value, new ArrayList<>());
}
field.setAccessible(true);
classMap.get(value).add(field);
}
}
);
//索引-->columns
Map<Integer, List<Field>> reflectionMap = new HashMap<>(16);
//默认读取第一个sheet
Sheet sheet = workbook.getSheetAt(0);
boolean firstRow = true;
for (int i = startRow; i <= sheet.getLastRowNum(); i++) {
Row row = sheet.getRow(i);
// 提取注解
if (firstRow) {
for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
Cell cell = row.getCell(j);
String cellValue = getCellValue(cell);
if (classMap.containsKey(cellValue)) {
reflectionMap.put(j, classMap.get(cellValue));
}
}
if (reflectionMap.size() > 0) {
firstRow = false;
}
} else {
//忽略空白行
if (row == null) {
continue;
}
try {
T t = cls.newInstance();
//判断是否为空白行
boolean allBlank = true;
for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
if (reflectionMap.containsKey(j)) {
Cell cell = row.getCell(j);
String cellValue = getCellValue(cell);
if (StringUtils.isNotBlank(cellValue)) {
allBlank = false;
}
List<Field> fieldList = reflectionMap.get(j);
fieldList.forEach(
x -> {
try {
handleField(t, cellValue, x);
} catch (Exception e) {
log.error(String.format("reflect field:%s value:%s exception!", x.getName(), cellValue), e);
}
}
);
}
}
if (!allBlank) {
dataList.add(t);
} else {
log.warn(String.format("row:%s is blank ignore!", i));
}
} catch (Exception e) {
log.error(String.format("parse row:%s exception!", i), e);
}
}
}
}
} catch (Exception e) {
log.error(String.format("parse excel exception!"), e);
} finally {
if (workbook != null) {
try {
workbook.close();
} catch (Exception e) {
log.error(String.format("parse excel exception!"), e);
}
}
}
return dataList;
}
private static <T> void handleField(T t, String value, Field field) throws Exception {
Class<?> type = field.getType();
if (type == null || type == void.class || StringUtils.isBlank(value)) {
return;
}
if (type == Object.class) {
field.set(t, value);
//数字类型
} else if (type.getSuperclass() == null || type.getSuperclass() == Number.class) {
if (type == int.class || type == Integer.class) {
field.set(t, NumberUtils.toInt(value));
} else if (type == long.class || type == Long.class) {
field.set(t, NumberUtils.toLong(value));
} else if (type == byte.class || type == Byte.class) {
field.set(t, NumberUtils.toByte(value));
} else if (type == short.class || type == Short.class) {
field.set(t, NumberUtils.toShort(value));
} else if (type == double.class || type == Double.class) {
field.set(t, NumberUtils.toDouble(value));
} else if (type == float.class || type == Float.class) {
field.set(t, NumberUtils.toFloat(value));
} else if (type == char.class || type == Character.class) {
field.set(t, CharUtils.toChar(value));
} else if (type == boolean.class) {
field.set(t, BooleanUtils.toBoolean(value));
} else if (type == BigDecimal.class) {
field.set(t, new BigDecimal(value));
}
} else if (type == Boolean.class) {
field.set(t, BooleanUtils.toBoolean(value));
} else if (type == Date.class) {
//
field.set(t, value);
} else if (type == String.class) {
field.set(t, value);
} else {
Constructor<?> constructor = type.getConstructor(String.class);
field.set(t, constructor.newInstance(value));
}
}
private static String getCellValue(Cell cell) {
if (cell == null) {
return "";
}
if (cell.getCellType() == Cell.CELL_TYPE_NUMERIC) {
if (HSSFDateUtil.isCellDateFormatted(cell)) {
return HSSFDateUtil.getJavaDate(cell.getNumericCellValue()).toString();
} else {
return new BigDecimal(cell.getNumericCellValue()).toString();
}
} else if (cell.getCellType() == Cell.CELL_TYPE_STRING) {
return StringUtils.trimToEmpty(cell.getStringCellValue());
} else if (cell.getCellType() == Cell.CELL_TYPE_FORMULA) {
return StringUtils.trimToEmpty(cell.getCellFormula());
} else if (cell.getCellType() == Cell.CELL_TYPE_BLANK) {
return "";
} else if (cell.getCellType() == Cell.CELL_TYPE_BOOLEAN) {
return String.valueOf(cell.getBooleanCellValue());
} else if (cell.getCellType() == Cell.CELL_TYPE_ERROR) {
return "ERROR";
} else {
return cell.toString().trim();
}
}
public static <T> void writeExcel(HttpServletResponse response, List<T> dataList, Class<T> cls) {
Field[] fields = cls.getDeclaredFields();
List<Field> fieldList = Arrays.stream(fields)
.filter(field -> {
ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
if (annotation != null && annotation.col() > 0) {
field.setAccessible(true);
return true;
}
return false;
}).sorted(Comparator.comparing(field -> {
int col = 0;
ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
if (annotation != null) {
col = annotation.col();
}
return col;
})).collect(Collectors.toList());
Workbook wb = new XSSFWorkbook();
Sheet sheet = wb.createSheet("Sheet1");
AtomicInteger ai = new AtomicInteger();
{
Row row = sheet.createRow(ai.getAndIncrement());
AtomicInteger aj = new AtomicInteger();
//写入头部
fieldList.forEach(field -> {
ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
String columnName = "";
if (annotation != null) {
columnName = annotation.value();
}
Cell cell = row.createCell(aj.getAndIncrement());
CellStyle cellStyle = wb.createCellStyle();
cellStyle.setFillForegroundColor(IndexedColors.WHITE.getIndex());
cellStyle.setFillPattern(CellStyle.SOLID_FOREGROUND);
cellStyle.setAlignment(CellStyle.ALIGN_CENTER);
Font font = wb.createFont();
font.setBoldweight(Font.BOLDWEIGHT_NORMAL);
cellStyle.setFont(font);
cell.setCellStyle(cellStyle);
cell.setCellValue(columnName);
});
}
if (CollectionUtils.isNotEmpty(dataList)) {
dataList.forEach(t -> {
Row row1 = sheet.createRow(ai.getAndIncrement());
AtomicInteger aj = new AtomicInteger();
fieldList.forEach(field -> {
Class<?> type = field.getType();
Object value = "";
try {
value = field.get(t);
} catch (Exception e) {
e.printStackTrace();
}
Cell cell = row1.createCell(aj.getAndIncrement());
if (value != null) {
if (type == Date.class) {
cell.setCellValue(value.toString());
} else {
cell.setCellValue(value.toString());
}
cell.setCellValue(value.toString());
}
});
});
}
//冻结窗格
wb.getSheet("Sheet1").createFreezePane(0, 1, 0, 1);
//浏览器下载excel
buildExcelDocument("导出数据.xlsx", wb, response);
//生成excel文件
// buildExcelFile(".\\default.xlsx", wb);
}
private static void buildExcelDocument(String fileName, Workbook wb, HttpServletResponse response) {
try {
response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "utf-8"));
response.flushBuffer();
wb.write(response.getOutputStream());
} catch (IOException e) {
e.printStackTrace();
}
}
private static void buildExcelFile(String path, Workbook wb) {
File file = new File(path);
if (file.exists()) {
file.delete();
}
try {
wb.write(new FileOutputStream(file));
} catch (Exception e) {
e.printStackTrace();
}
}
}
四、定义导出实体类
主要是使用这里的@ExcelColumn注解，其中的col从0开始的。
package com.cloud.library.model.role;
import com.cloud.core.annotation.ExcelColumn;
import lombok.Data;
@Data
public class SysRoleExcel {
@ExcelColumn(value = "姓名", col = 1)
private String name;
@ExcelColumn(value = "描述", col = 2)
private String description;
}
Excel对应的模板参考
五、Controller层代码编写
//region 导入数据
@RequestMapping(value = "/readExcel", method = RequestMethod.POST)
public void readExcel(@RequestParam(value = "uploadFile", required = false) MultipartFile file) {
List<SysRoleExcel> list = CustomExcelUtils.readExcel("", SysRoleExcel.class, 0, file);
List<SysRole> sysRoleList = new ArrayList<>();
list.forEach(e -> {
SysRole sysRole = new SysRole();
BeanUtils.copyProperties(e, sysRole);
sysRoleList.add(sysRole);
});
sysRoleService.saveBatch(sysRoleList);
}
// endregion
这里发现了，这个saveBatch可以直接使用雪花的id来保存数据，因为这里用的是mybatis-plus，单条数据保存使用的是它的配置。然后试了下，批量导入也是可以的，另外，这个批量保存，理论上没有条数限制，这个还等待后续测试。
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