最近在项目开发中，有需要导入、导出excel的功能，使用了alibaba的easyexcel。自己水平太菜，踩了许多坑。在alibaba-easyexcel使用问题总结 这里总结了一番，也涨了点姿势：
- 恶补了下maven的相关知识：maven包冲突的解决方式
- 如果机器上装了“中软防水坝”等相关的安全软件，文件读写是要失败的。因为 inputStream.markSupported()会返回false 从而无法操作 抛出异常 easyexcel是ExcelAnalysisException
io is must be available markSupported。
发现easyexcel也是引用了apache的poi，在poi基础上做了更改。
今天也来学习下使用poi 3.17来导入、导出excel
参考自这里，写的很好，跟着撸一遍
maven依赖
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-collections4</artifactId>
<version>4.1</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>
<dependency>
<groupId>org.apache.xmlbeans</groupId>
<artifactId>xmlbeans</artifactId>
<version>2.6.0</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.17</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.17</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml-schemas</artifactId>
<version>3.17</version>
</dependency>
如果你想简化你的代码，可以加上
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.16.10</version>
<scope>provided</scope>
</dependency>
导入
准备excel表 人员信息.xlsx
创建与excel列名对应的bean
package io.github.newmean.demo.domain;
import lombok.Data;
import java.util.Date;
@Data
public class Persion {
private String deptName;
private String createName;
private Date createDate;
private String politicStatus;
private int age;
}
Lombok 注解在线帮助文档：http://projectlombok.org/features/index
介绍几个常用的 lombok 注解：
- @Data ：注解在类上；提供类所有属性的 get 和 set 方法，此外还提供了equals、canEqual、hashCode、toString 方法
- @Setter：注解在属性上；为属性提供 sett方法
- @Getter：注解在属性上；为属性提供 get 方法
- @Log4j ：注解在类上；为类提供一个 属性名为log 的 log4j 日志对象
- @NoArgsConstructor：注解在类上；为类提供一个无参的构造方法
- @AllArgsConstructor：注解在类上；为类提供一个全参的构造方法
再加上一个注解，让属性和列名对应起来
package io.github.newmean.demo.annotation;
import java.lang.annotation.*;
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ExcelColumn {
public String value() default "";
}
那么bean就可以改写为：
package io.github.newmean.demo.domain;
import io.github.newmean.demo.util.ExcelColumn;
import lombok.Data;
import lombok.Setter;
import lombok.ToString;
import java.util.Date;
@Data
@ToString
public class Persion {
@Setter
@ExcelColumn(value = "处室")
private String deptName;
@Setter
@ExcelColumn(value = "填表人")
private String createName;
@Setter
@ExcelColumn(value = "填表时间")
private Date createDate;
@Setter
@ExcelColumn(value = "政治面貌")
private String politicStatus;
@Setter
@ExcelColumn(value = "年龄")
private int age;
}
采用MultipartFile上传，可以读取.xlsx或者.xls格式的Excel(POI3.15以上版本兼容)
package io.github.newmean.demo.util;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import io.github.newmean.demo.annotation.ExcelColumn;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.time.FastDateFormat;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;
import org.springframework.util.StringUtils;
import org.springframework.web.multipart.MultipartFile;
public class ExcelUtil {
private static final DecimalFormat DECIMAL_FORMAT = new DecimalFormat("0");// 格式化 number为整
private static final FastDateFormat FAST_DATE_FORMAT = FastDateFormat.getInstance("yyyy-MM-dd HH:mm:ss");
/**
* 对外提供读取excel 的方法
* @param file
* @return
* @throws IOException
*/
public static List<List<Object>> readExcel(MultipartFile file) throws IOException {
String extension = file.getOriginalFilename().substring(file.getOriginalFilename().lastIndexOf(".") + 1).toLowerCase();
if(Objects.equals("xls", extension) || Objects.equals("xlsx", extension)) {
return readExcel(file.getInputStream());
} else {
throw new IOException("不支持的文件类型");
}
}
/**
* 对外提供读取excel 的方法
* @param file
* @param cls
* @return
* @throws IOException
*/
public static <T> List<T> readExcel(MultipartFile file, Class<T> cls) throws IOException {
String extension = file.getOriginalFilename().substring(file.getOriginalFilename().lastIndexOf(".") + 1).toLowerCase();
if(Objects.equals("xls", extension) || Objects.equals("xlsx", extension)) {
return readExcel(file.getInputStream(), cls);
} else {
throw new IOException("不支持的文件类型");
}
}
/**
* 读取 office excel
*
* @param inputStream
* @return
* @throws IOException
*/
public static List<List<Object>> readExcel(InputStream inputStream) throws IOException {
List<List<Object>> list = new LinkedList<>();
Workbook workbook = null;
try {
workbook = WorkbookFactory.create(inputStream);
int sheetsNumber = workbook.getNumberOfSheets();
for (int n = 0; n < sheetsNumber; n++) {
Sheet sheet = workbook.getSheetAt(n);
Object value = null;
Row row = null;
Cell cell = null;
for (int i = sheet.getFirstRowNum() + 1; i <= sheet.getPhysicalNumberOfRows(); i++) { // 从第二行开始读取
row = sheet.getRow(i);
if (StringUtils.isEmpty(row)) {
continue;
}
List<Object> linked = new LinkedList<>();
for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
cell = row.getCell(j);
if (StringUtils.isEmpty(cell)) {
continue;
}
value = getCellValue(cell);
linked.add(value);
}
list.add(linked);
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
IOUtils.closeQuietly(workbook);
IOUtils.closeQuietly(inputStream);
}
return list;
}
/**
* 获取excel数据 将之转换成bean
* @param cls
* @param <T>
* @return
*/
public static <T> List<T> readExcel(InputStream inputStream, Class<T> cls) {
List<T> dataList = new LinkedList<>();
Workbook workbook = null;
try {
workbook = WorkbookFactory.create(inputStream);
Map<String, List<Field>> classMap = new HashMap<>();
Field[] fields = cls.getDeclaredFields();
for (Field field : fields) {
ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
if (annotation != null) {
String value = annotation.value();
if (!classMap.containsKey(value)) {
classMap.put(value, new ArrayList<>());
}
field.setAccessible(true);
classMap.get(value).add(field);
}
}
Map<Integer, List<Field>> reflectionMap = new HashMap<>();
int sheetsNumber = workbook.getNumberOfSheets();
for (int n = 0; n < sheetsNumber; n++) {
Sheet sheet = workbook.getSheetAt(n);
for (int j = sheet.getRow(0).getFirstCellNum(); j < sheet.getRow(0).getLastCellNum(); j++) { //首行提取注解
Object cellValue = getCellValue(sheet.getRow(0).getCell(j));
if (classMap.containsKey(cellValue)) {
reflectionMap.put(j, classMap.get(cellValue));
}
}
Row row = null;
Cell cell = null;
for (int i = sheet.getFirstRowNum() + 1; i < sheet.getPhysicalNumberOfRows(); i++) {
row = sheet.getRow(i);
T t = cls.newInstance();
for (int j = row.getFirstCellNum(); j < row.getLastCellNum(); j++) {
cell = row.getCell(j);
if (reflectionMap.containsKey(j)) {
Object cellValue = getCellValue(cell);
List<Field> fieldList = reflectionMap.get(j);
for (Field field : fieldList) {
try {
field.set(t, cellValue);
} catch (Exception e) {
//logger.error()
}
}
}
}
dataList.add(t);
}
}
} catch (Exception e) {
dataList = null;
} finally {
IOUtils.closeQuietly(workbook);
IOUtils.closeQuietly(inputStream);
}
return dataList;
}
/**
* 获取excel 单元格数据
*
* @param cell
* @return
*/
private static Object getCellValue(Cell cell) {
Object value = null;
switch (cell.getCellTypeEnum()) {
case _NONE:
break;
case STRING:
value = cell.getStringCellValue();
break;
case NUMERIC:
if(DateUtil.isCellDateFormatted(cell)){ //日期
value = FAST_DATE_FORMAT.format(DateUtil.getJavaDate(cell.getNumericCellValue()));
} else if("@".equals(cell.getCellStyle().getDataFormatString())
|| "General".equals(cell.getCellStyle().getDataFormatString())
|| "0_ ".equals(cell.getCellStyle().getDataFormatString())){
//文本 or 常规 or 整型数值
value = DECIMAL_FORMAT.format(cell.getNumericCellValue());
}
break;
case BOOLEAN:
value = cell.getBooleanCellValue();
break;
case BLANK:
//value = ",";
break;
default:
value = cell.toString();
}
return value;
}
}
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