本文将介绍使用EasyExcel实现识别单行表头的一种实现方式。主要是通过实现AnalysisEventListener 抽象类，并覆写其 hasNext 和 invokeHead 方法。
Jar依赖
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>easyexcel</artifactId>
<version>3.3.4</version>
</dependency>
<dependency>
<groupId>org.reflections</groupId>
<artifactId>reflections</artifactId>
<version>0.10.2</version>
</dependency>实现代码
一个表头基类和2个子类，一个用于表头字段的类。
注意：代码使用反射，使用了@ExcelProperty(value = “地址”, index = 0)注解，index用于表头字段排序，value用于表头显示的名称。
1.表头基类
package top.jyokiyi.my.test.excel;
import lombok.Data;
@Data
public class ExcelBaseModel {
}2.表头实现类1
继承表头基类：
package top.jyokiyi.my.test.excel;
import com.alibaba.excel.annotation.ExcelProperty;
import lombok.Data;
@Data
public class ExcelHeadTest1Model extends ExcelBaseModel {
@ExcelProperty(value = "地址", index = 0)
private String address;
@ExcelProperty(value = "名称", index = 1)
private String name;
}3.表头实现类2
继承表头基类：
package top.jyokiyi.my.test.excel;
import com.alibaba.excel.annotation.ExcelProperty;
import lombok.Data;
@Data
public class ExcelHeadTest2Model extends ExcelBaseModel {
@ExcelProperty(value = "邮件",index = 0)
private String email;
@ExcelProperty(value = "内容", index = 1)
private String content;
}
4. 表头字段类
package top.jyokiyi.my.test.excel;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
@Builder
@NoArgsConstructor
@AllArgsConstructor
@Data
public class ExcelHeadFieldModel {
/**
* 列号
*/
private Integer column;
/**
* 表头描述
*/
private String headDesc;
}5. 使用Reflections实现查找所有子类
注意：这里直接指定了包名，且子类和基类在同一个包中。（如有需要可自行修改，以实现自己的需求）
/**
* 获取指定类的所有子类
* @param clazz
* @param <T>
* @return
*/
public static <T>Set<Class<? extends T>> getAllSubTypes(Class<T> clazz) {
Set<Class<? extends T>> subTypeClassSet = new HashSet<>();
Reflections reflections = new Reflections("top.jyokiyi.my.test.excel");
Set<Class<? extends T>> subTypesOf = reflections.getSubTypesOf(clazz);
if (CollectionUtils.isNotEmpty(subTypesOf)) {
subTypeClassSet.addAll(subTypesOf);
}
return subTypeClassSet;
}6.表头类型与表头字段集合映射
/**
* 将表头与对于的类映射起来
* @param sets
* @param <T>
* @return
*/
public static <T>Map<Class<? extends T>, List<ExcelHeadFieldModel>> getHeadMapForExcelProperty(Set<Class<? extends T>> sets) {
Map<Class<? extends T>, List<ExcelHeadFieldModel>> maps = new HashMap<>();
for (Class<? extends T> clz : sets) {
List<ExcelHeadFieldModel> fieldModelList = new ArrayList<>();
try {
Field[] fields = clz.getDeclaredFields();
for (Field field : fields) {
if (field.isAnnotationPresent(ExcelProperty.class)) {
ExcelProperty annotation = field.getAnnotation(ExcelProperty.class);
fieldModelList.add(ExcelHeadFieldModel.builder()
.column(annotation.index()).headDesc(annotation.value()[0]).build());
}
}
} catch (Exception e) {
e.printStackTrace();
}
if (CollectionUtils.isNotEmpty(fieldModelList)) {
maps.put(clz, fieldModelList.stream()
.sorted(Comparator.comparing(ExcelHeadFieldModel::getColumn))
.collect(Collectors.toList()));
}
}
return maps;
}7.实现监听类
继承easy excel 的 AnalysisEventListener 抽象类，并覆写其 hasNext 和 invokeHead 方法。
package top.jyokiyi.my.test.excel;
import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.alibaba.excel.metadata.data.ReadCellData;
import com.alibaba.excel.util.StringUtils;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
public class ExcelHeaderIdentifyListener extends AnalysisEventListener<Map<Integer, String>> {
private static ThreadLocal<Class<? extends ExcelBaseModel>> classResult = new ThreadLocal<>();
public ThreadLocal<Class<? extends ExcelBaseModel>> getClassResult() {
return classResult;
}
public void clear() {
classResult.remove();
}
/**
* 返回false，读取一行后，不再继续读取
*
* @param context
* @return
*/
@Override
public boolean hasNext(AnalysisContext context) {
return false;
}
/**
* 根据表头解析获取对应的表头子类
* @param headMap
* @param context
*/
@Override
public void invokeHead(Map<Integer, ReadCellData<?>> headMap, AnalysisContext context) {
List<ExcelHeadFieldModel> headFieldModels = headMap.values().stream().map(column -> ExcelHeadFieldModel.builder()
.column(column.getColumnIndex()).headDesc(column.getStringValue()).build())
.sorted(Comparator.comparing(ExcelHeadFieldModel::getColumn))
.collect(Collectors.toList());
// 将表头字段拼接起来
String joinStr = headFieldModels.stream()
.map(ExcelHeadFieldModel::getHeadDesc)
.collect(Collectors.joining());
// 获取表头基类的所有子类信息
Set<Class<? extends ExcelBaseModel>> allSubTypes = ClassUtils.getAllSubTypes(ExcelBaseModel.class);
// 将class和表头映射起来
Map<Class<? extends ExcelBaseModel>, List<ExcelHeadFieldModel>> listMap = ClassUtils.getHeadMapForExcelProperty(allSubTypes);
// 查找对应的子类
for (Map.Entry<Class<? extends ExcelBaseModel>, List<ExcelHeadFieldModel>> entry : listMap.entrySet()) {
if (entry.getValue().size() == headFieldModels.size() && StringUtils.equals(joinStr, entry.getValue()
.stream().map(ExcelHeadFieldModel::getHeadDesc).collect(Collectors.joining()))) {
classResult.set(entry.getKey());
break;
}
}
}
@Override
public void invoke(Map<Integer, String> data, AnalysisContext context) {
}
@Override
public void doAfterAllAnalysed(AnalysisContext context) {
}
}
8.测试
package top.jyokiyi.my.test.excel;
import com.alibaba.excel.EasyExcel;
import java.io.File;
import java.io.FileInputStream;
public class ReadTest {
public static void main(String[] args) throws Exception {
ExcelHeaderIdentifyListener listener = new ExcelHeaderIdentifyListener();
String dir = System.getProperty("user.dir");
String filePath = dir + File.separator + "src" + File.separator + "test_excel.xlsx";
EasyExcel.read(new FileInputStream(filePath), listener)
.sheet().doRead();
Class<? extends ExcelBaseModel> aClass = listener.getClassResult();
listener.clear();
System.out.println(aClass.getName());
}
}
测试结果：
top.jyokiyi.my.test.excel.ExcelHeadTest1Model测试文件的表头如下：
| 地址 | 名称 |
| 1 | 2 |