SpringBoot集成EasyExcel实现Excel导入代码方法

本篇文章小编给大家分享一下SpringBoot集成EasyExcel实现Excel导入代码方法，文章代码介绍的很详细，小编觉得挺不错的，现在分享给大家供大家参考，有需要的小伙伴们可以来看看。

一、背景

阿里巴巴语雀团队对EasyExcel是这样介绍的

Java解析、生成Excel比较有名的框架有Apache poi、jxl。但他们都存在一个严重的问题就是非常的耗内存，

poi有一套SAX模式的API可以一定程度的解决一些内存溢出的问题，但POI还是有一些缺陷，比如07版Excel解压

缩以及解压后存储都是在内存中完成的，内存消耗依然很大。easyexcel重写了poi对07版Excel的解析，能够原

本一个3M的excel用POI sax依然需要100M左右内存降低到几M，并且再大的excel不会出现内存溢出，03版依赖

POI的sax模式。在上层做了模型转换的封装，让使用者更加简单方便。

当然还有急速模式能更快，但是内存占用会在100M多一点。

二、集成EasyExcel？

萨达

1、 在pom.xml中添加EasyExcel依赖

 
   com.alibaba
   easyexcel
   2.1.3
  

2、创建EasyExcel映射实体类

import com.alibaba.excel.annotation.ExcelProperty;

public class ExcelEntity {
 // ExcelProperty中的参数要对应Excel中的标题
 @ExcelProperty("ID")
 private int ID;

 @ExcelProperty("NAME")
 private String name;

 @ExcelProperty("AGE")
 private int age;

 public ExcelEntity() {
 }

 public ExcelEntity(int ID, String name, int age) {
  this.ID = ID;
  this.name = name;
  this.age = age;
 }

 public int getID() {
  return ID;
 }

 public void setID(int ID) {
  this.ID = ID;
 }

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }

 public int getAge() {
  return age;
 }

 public void setAge(int age) {
  this.age = age;
 }
}

3、创建自定义Easyexcel的监听类

这个监听类里面每一个ExcelEntity对象代表一行数据

在这个监听类里面可以对读取到的每一行数据进行单独操作

这里的读取的数据是按照Excel中每一条数据的顺序进行读取的

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import java.util.ArrayList;
import java.util.List;

public class UploadExcelListener extends AnalysisEventListener {

 private static final Logger logger = LoggerFactory.getLogger(LoggerItemController.class);
 public static final List list = new ArrayList<>();

 @Override
 public void invoke(ExcelEntity excelEntity, AnalysisContext context) {
  logger.info(String.valueOf(excelEntity.getID()));
  logger.info(excelEntity.getName());
  logger.info(String.valueOf(excelEntity.getAge()));
  list.add(excelEntity);
 }

4、创建controller

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelReader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

@RestController
@CrossOrigin
@RequestMapping("/loggerItem")
public class LoggerItemController {


 // MultipartFile 这个类一般是用来接受前台传过来的文件
 @PostMapping("/upload")
 public List upload(@RequestParam(value = "multipartFile") MultipartFile multipartFile){
  if (multipartFile == null){
   return null;
  }

  InputStream in = null;
  try {
   // 从multipartFile获取InputStream流
   in = multipartFile.getInputStream();

   /*
    * EasyExcel 有多个不同的read方法，适用于多种需求
    * 这里调用EasyExcel中通过InputStream流方式读取Excel的Read方法
    * 他会返回一个ExcelReaderBuilder类型的返回值
    * ExcelReaderBuilder中有一个doReadAll方法，会读取所有的Sheet
    */
   EasyExcel.read(in,ExcelEntity.class,new UploadExcelListener())
     .sheet("Sheet1")
     .doRead();

   // 每次EasyExcel的read方法读取完之后都会关闭流，我这里为了试验doReadAll方法，所以重新获取了一次
   in = multipartFile.getInputStream();
   /*
    * ExcelReaderBuilder中的Sheet方法，需要添加读取的Sheet名作为参数
    * 并且不要忘记在后面再调用一下doReadAll方法，否则不会进行读取操作
    */

   EasyExcel.read(in,ExcelEntity.class,new UploadExcelListener()).doReadAll();
  } catch (IOException e) {
   e.printStackTrace();
  }
  return UploadExcelListener.list;
 }
}

5、apppcation.yml配置

server:
 # 指定端口号
 port: 8080
spring:
 servlet:
 multipart:
  # 配置单个上传文件大小
  file-size-threshold: 100M
  # 配置总上传大小
  max-request-size: 300M

6、测试

我们先搞一个简单的Excel，用来测试

然后通过Postman模拟发送请求

选择Post请求并输入请求地址

在下面选择Body

Key的框中输入controller中的请求的方法中的参数，后面的下拉框中选择File

VALUE框中有一个Select File ，点击后选择自己刚才创建的测试的Excel

最后点击Send发送请求

返回值如下：

由于我读了两次都放在同一个pst中返回，所以返回值中有8个对象。

[
 {
  "name": "小黑",
  "age": 25,
  "id": 1
 },
 {
  "name": "小白",
  "age": 22,
  "id": 2
 },
 {
  "name": "小黄",
  "age": 22,
  "id": 3
 },
 {
  "name": "小绿",
  "age": 23,
  "id": 4
 },
 {
  "name": "小黑",
  "age": 25,
  "id": 1
 },
 {
  "name": "小白",
  "age": 22,
  "id": 2
 },
 {
  "name": "小黄",
  "age": 22,
  "id": 3
 },
 {
  "name": "小绿",
  "age": 23,
  "id": 4
 }
]

三、EasyExcel中的Read方法汇总

/**
  * Build excel the read
  *
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read() {
  return new ExcelReaderBuilder();
 }

 /**
  * Build excel the read
  *
  * @param file
  *   File to read.
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read(File file) {
  return read(file, null, null);
 }

 /**
  * Build excel the read
  *
  * @param file
  *   File to read.
  * @param readListener
  *   Read listener.
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read(File file, ReadListener readListener) {
  return read(file, null, readListener);
 }

 /**
  * Build excel the read
  *
  * @param file
  *   File to read.
  * @param head
  *   Annotate the class for configuration information.
  * @param readListener
  *   Read listener.
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read(File file, Class head, ReadListener readListener) {
  ExcelReaderBuilder excelReaderBuilder = new ExcelReaderBuilder();
  excelReaderBuilder.file(file);
  if (head != null) {
   excelReaderBuilder.head(head);
  }
  if (readListener != null) {
   excelReaderBuilder.registerReadListener(readListener);
  }
  return excelReaderBuilder;
 }

 /**
  * Build excel the read
  *
  * @param pathName
  *   File path to read.
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read(String pathName) {
  return read(pathName, null, null);
 }

 /**
  * Build excel the read
  *
  * @param pathName
  *   File path to read.
  * @param readListener
  *   Read listener.
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read(String pathName, ReadListener readListener) {
  return read(pathName, null, readListener);
 }

 /**
  * Build excel the read
  *
  * @param pathName
  *   File path to read.
  * @param head
  *   Annotate the class for configuration information.
  * @param readListener
  *   Read listener.
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read(String pathName, Class head, ReadListener readListener) {
  ExcelReaderBuilder excelReaderBuilder = new ExcelReaderBuilder();
  excelReaderBuilder.file(pathName);
  if (head != null) {
   excelReaderBuilder.head(head);
  }
  if (readListener != null) {
   excelReaderBuilder.registerReadListener(readListener);
  }
  return excelReaderBuilder;
 }

 /**
  * Build excel the read
  *
  * @param inputStream
  *   Input stream to read.
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read(InputStream inputStream) {
  return read(inputStream, null, null);
 }

 /**
  * Build excel the read
  *
  * @param inputStream
  *   Input stream to read.
  * @param readListener
  *   Read listener.
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read(InputStream inputStream, ReadListener readListener) {
  return read(inputStream, null, readListener);
 }

 /**
  * Build excel the read
  *
  * @param inputStream
  *   Input stream to read.
  * @param head
  *   Annotate the class for configuration information.
  * @param readListener
  *   Read listener.
  * @return Excel reader builder.
  */
 public static ExcelReaderBuilder read(InputStream inputStream, Class head, ReadListener readListener) {
  ExcelReaderBuilder excelReaderBuilder = new ExcelReaderBuilder();
  excelReaderBuilder.file(inputStream);
  if (head != null) {
   excelReaderBuilder.head(head);
  }
  if (readListener != null) {
   excelReaderBuilder.registerReadListener(readListener);
  }
  return excelReaderBuilder;
 }

所有的方法都在这儿了，其实如果看不懂到底应该调用哪一个read方法的话，可以以根据自己所能得到的参数来判断。

四、扩展

读取本地Excel

public static void main(String[] args) {
 EasyExcel.read("C:/Users/Lonely Programmer/Desktop/新建 Microsoft Excel 工作表.xlsx"
     ,ExcelEntity.class
     ,new UploadExcelListener())
  .doReadAll();
}

读取本地的Excel和通过InPutStream流读取的方式是一样的，只是参数变了，原本传的是InPutStream流，现在传的是文件的绝对路径。我这里监听类和映射实体类都没有变，和上传用的是同一个，大家也可以根据需求来设定自己的监听类与实体类

MultipartFile文档

MultipartFile文档地址：https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/multipart/MultipartFile.html

翻译是通过Google Chrome自带翻译插件进行翻译的，建议大家使用Google Chrome打开，自带翻译功能