JAVA使用easyexcel操作Excel

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                    本文链接：https://blog.csdn.net/jianggujin/article/details/80200400







                                            之前写过一篇《JAVA操作Excel》，介绍了jxl和poi读写Excel的实现，今天为大家介绍一下使用easyexcel对Excel进行读写，项目主页地址：https://github.com/alibaba/easyexcel

作者对easyexcel的介绍是：

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KB级别，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

使用easyexcel，首先我们需要添加maven依赖：

<dependency>
   <groupId>com.alibaba</groupId>
   <artifactId>easyexcel</artifactId>
   <version>1.0.1</version>
</dependency>12345

首先，我们先来看看如何写Excel，写入Excel，我们可以通过com.alibaba.excel.ExcelWriter类实现，下面我们来看一下最简单的无表头的实现

package test;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.junit.Test;

import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.metadata.Sheet;
import com.alibaba.excel.support.ExcelTypeEnum;

public class ExcelWriteTest {

   /**
    * 每行数据是List<String>无表头
    *
    * @throws IOException
    */
   @Test
   public void writeWithoutHead() throws IOException {
      try (OutputStream out = new FileOutputStream("withoutHead.xlsx");) {
         ExcelWriter writer = new ExcelWriter(out, ExcelTypeEnum.XLSX, false);
         Sheet sheet1 = new Sheet(1, 0);
         sheet1.setSheetName("sheet1");
         List<List<String>> data = new ArrayList<>();
         for (int i = 0; i < 100; i++) {
            List<String> item = new ArrayList<>();
            item.add("item0" + i);
            item.add("item1" + i);
            item.add("item2" + i);
            data.add(item);
         }
         writer.write0(data, sheet1);
         writer.finish();
      }
   }
}12345678910111213141516171819202122232425262728293031323334353637383940

生成的Excel样式如下：

很多时候，我们在生成Excel的时候都是需要添加表头的，使用easyexcel可以很容易的实现，我们可以对上面的例子进行简单的改造，为其添加表头

package test;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.junit.Test;

import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.metadata.Sheet;
import com.alibaba.excel.metadata.Table;
import com.alibaba.excel.support.ExcelTypeEnum;

public class ExcelWriteTest {

   @Test
   public void writeWithoutHead() throws IOException {
      try (OutputStream out = new FileOutputStream("withHead.xlsx");) {
         ExcelWriter writer = new ExcelWriter(out, ExcelTypeEnum.XLSX);
         Sheet sheet1 = new Sheet(1, 0);
         sheet1.setSheetName("sheet1");
         List<List<String>> data = new ArrayList<>();
         for (int i = 0; i < 100; i++) {
            List<String> item = new ArrayList<>();
            item.add("item0" + i);
            item.add("item1" + i);
            item.add("item2" + i);
            data.add(item);
         }
         List<List<String>> head = new ArrayList<List<String>>();
         List<String> headCoulumn1 = new ArrayList<String>();
         List<String> headCoulumn2 = new ArrayList<String>();
         List<String> headCoulumn3 = new ArrayList<String>();
         headCoulumn1.add("第一列");
         headCoulumn2.add("第二列");
         headCoulumn3.add("第三列");
         head.add(headCoulumn1);
         head.add(headCoulumn2);
         head.add(headCoulumn3);
         Table table = new Table(1);
         table.setHead(head);
         writer.write0(data, sheet1, table);
         writer.finish();
      }
   }
}123456789101112131415161718192021222324252627282930313233343536373839404142434445464748

效果如下：

除了上面添加表头的方式，我们还可以使用实体类，为其添加com.alibaba.excel.annotation.ExcelProperty注解来生成表头，实体类数据作为Excel数据

package test;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.junit.Test;

import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.metadata.BaseRowModel;
import com.alibaba.excel.metadata.Sheet;
import com.alibaba.excel.metadata.Table;
import com.alibaba.excel.support.ExcelTypeEnum;

public class ExcelWriteTest {

   @Test
   public void writeWithHead() throws IOException {
      try (OutputStream out = new FileOutputStream("withHead.xlsx");) {
         ExcelWriter writer = new ExcelWriter(out, ExcelTypeEnum.XLSX);
         Sheet sheet1 = new Sheet(1, 0, ExcelPropertyIndexModel.class);
         sheet1.setSheetName("sheet1");
         List<ExcelPropertyIndexModel> data = new ArrayList<>();
         for (int i = 0; i < 100; i++) {
            ExcelPropertyIndexModel item = new ExcelPropertyIndexModel();
            item.name = "name" + i;
            item.age = "age" + i;
            item.email = "email" + i;
            item.address = "address" + i;
            item.sax = "sax" + i;
            item.heigh = "heigh" + i;
            item.last = "last" + i;
            data.add(item);
         }
         writer.write(data, sheet1);
         writer.finish();
      }
   }

public static class ExcelPropertyIndexModel extends BaseRowModel {

@ExcelProperty(value = "姓名", index = 0)
private String name;

@ExcelProperty(value = "年龄", index = 1)
private String age;

@ExcelProperty(value = "邮箱", index = 2)
private String email;

@ExcelProperty(value = "地址", index = 3)
private String address;

@ExcelProperty(value = "性别", index = 4)
private String sax;

@ExcelProperty(value = "高度", index = 5)
private String heigh;

@ExcelProperty(value = "备注", index = 6)
private String last;

      public String getName() {
         return name;
      }

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

      public String getAge() {
         return age;
      }

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

      public String getEmail() {
         return email;
      }

      public void setEmail(String email) {
         this.email = email;
      }

      public String getAddress() {
         return address;
      }

      public void setAddress(String address) {
         this.address = address;
      }

      public String getSax() {
         return sax;
      }

      public void setSax(String sax) {
         this.sax = sax;
      }

      public String getHeigh() {
         return heigh;
      }

      public void setHeigh(String heigh) {
         this.heigh = heigh;
      }

      public String getLast() {
         return last;
      }

      public void setLast(String last) {
         this.last = last;
      }
   }
}123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122

效果如下：

如果单行表头表头还不满足需求，没关系，还可以使用多行复杂的表头

package test;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.junit.Test;

public class ExcelWriteTest {
   @Test
   public void writeWithMultiHead() throws IOException {
      try (OutputStream out = new FileOutputStream("withMultiHead.xlsx");) {
         ExcelWriter writer = new ExcelWriter(out, ExcelTypeEnum.XLSX);
         Sheet sheet1 = new Sheet(1, 0, MultiLineHeadExcelModel.class);
         sheet1.setSheetName("sheet1");
         List<MultiLineHeadExcelModel> data = new ArrayList<>();
         for (int i = 0; i < 100; i++) {
            MultiLineHeadExcelModel item = new MultiLineHeadExcelModel();
            item.p1 = "p1" + i;
            item.p2 = "p2" + i;
            item.p3 = "p3" + i;
            item.p4 = "p4" + i;
            item.p5 = "p5" + i;
            item.p6 = "p6" + i;
            item.p7 = "p7" + i;
            item.p8 = "p8" + i;
            item.p9 = "p9" + i;
            data.add(item);
         }
         writer.write(data, sheet1);
         writer.finish();
      }
   }

public static class MultiLineHeadExcelModel extends BaseRowModel {

@ExcelProperty(value = { "表头1", "表头1", "表头31" }, index = 0)
private String p1;

@ExcelProperty(value = { "表头1", "表头1", "表头32" }, index = 1)
private String p2;

@ExcelProperty(value = { "表头3", "表头3", "表头3" }, index = 2)
private String p3;

@ExcelProperty(value = { "表头4", "表头4", "表头4" }, index = 3)
private String p4;

@ExcelProperty(value = { "表头5", "表头51", "表头52" }, index = 4)
private String p5;

@ExcelProperty(value = { "表头6", "表头61", "表头611" }, index = 5)
private String p6;

@ExcelProperty(value = { "表头6", "表头61", "表头612" }, index = 6)
private String p7;

@ExcelProperty(value = { "表头6", "表头62", "表头621" }, index = 7)
private String p8;

@ExcelProperty(value = { "表头6", "表头62", "表头622" }, index = 8)
private String p9;

      public String getP1() {
         return p1;
      }

      public void setP1(String p1) {
         this.p1 = p1;
      }

      public String getP2() {
         return p2;
      }

      public void setP2(String p2) {
         this.p2 = p2;
      }

      public String getP3() {
         return p3;
      }

      public void setP3(String p3) {
         this.p3 = p3;
      }

      public String getP4() {
         return p4;
      }

      public void setP4(String p4) {
         this.p4 = p4;
      }

      public String getP5() {
         return p5;
      }

      public void setP5(String p5) {
         this.p5 = p5;
      }

      public String getP6() {
         return p6;
      }

      public void setP6(String p6) {
         this.p6 = p6;
      }

      public String getP7() {
         return p7;
      }

      public void setP7(String p7) {
         this.p7 = p7;
      }

      public String getP8() {
         return p8;
      }

      public void setP8(String p8) {
         this.p8 = p8;
      }

      public String getP9() {
         return p9;
      }

      public void setP9(String p9) {
         this.p9 = p9;
      }
   }
}123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145

效果如下：

怎么样，这些已经基本满足我们的日常需求了，easyexcel不仅支持上述几种形式，还支持在一个sheet中添加多个表

package test;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.junit.Test;

public class ExcelWriteTest {
   @Test
   public void writeWithMultiTable() throws IOException {
      try (OutputStream out = new FileOutputStream("withMultiTable.xlsx");) {
         ExcelWriter writer = new ExcelWriter(out, ExcelTypeEnum.XLSX);
         Sheet sheet1 = new Sheet(1, 0);
         sheet1.setSheetName("sheet1");

         // 数据全是List<String> 无模型映射关系
         Table table1 = new Table(1);
         List<List<String>> data1 = new ArrayList<>();
         for (int i = 0; i < 5; i++) {
            List<String> item = new ArrayList<>();
            item.add("item0" + i);
            item.add("item1" + i);
            item.add("item2" + i);
            data1.add(item);
         }
         writer.write0(data1, sheet1, table1);

         // 模型上有表头的注解
         Table table2 = new Table(2);
         table2.setClazz(MultiLineHeadExcelModel.class);
         List<MultiLineHeadExcelModel> data2 = new ArrayList<>();
         for (int i = 0; i < 5; i++) {
            MultiLineHeadExcelModel item = new MultiLineHeadExcelModel();
            item.p1 = "p1" + i;
            item.p2 = "p2" + i;
            item.p3 = "p3" + i;
            item.p4 = "p4" + i;
            item.p5 = "p5" + i;
            item.p6 = "p6" + i;
            item.p7 = "p7" + i;
            item.p8 = "p8" + i;
            item.p9 = "p9" + i;
            data2.add(item);
         }
         writer.write(data2, sheet1, table2);

         // 模型上没有注解，表头数据动态传入,此情况下模型field顺序与excel现实顺序一致
         List<List<String>> head = new ArrayList<List<String>>();
         List<String> headCoulumn1 = new ArrayList<String>();
         List<String> headCoulumn2 = new ArrayList<String>();
         List<String> headCoulumn3 = new ArrayList<String>();
         headCoulumn1.add("第一列");
         headCoulumn2.add("第二列");
         headCoulumn3.add("第三列");
         head.add(headCoulumn1);
         head.add(headCoulumn2);
         head.add(headCoulumn3);
         Table table3 = new Table(3);
         table3.setHead(head);
         writer.write0(data1, sheet1, table3);

         writer.finish();
      }
   }