目录
1，Easy Excel入门
1.1：Easy Excel概述
EasyExcel是一个基于Java的简单、省内存的读写Excel的开源项目。在尽可能节约内存的情况下支持读写百M的Excel工具。
官网:EasyExcel官方文档 – 基于Java的Excel处理工具 | Easy Excel
github地址：GitHub – alibaba/easyexcel: 快速、简洁、解决大文件内存溢出的java处理Excel工具
1.2：Easy Excel特点
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。
EasyExcel 重写了poi，使一个3M的excel只需要几M内存，并且再大的excel不会出现内存溢出。
64M内存1分钟内读取75M(46W行25列)的Excel。
1.3：环境搭建
1.3.1：测试父项目
项目名：zx-test-parent
-
修改pom文件
<dependencies> <!--测试--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-amqp</artifactId> </dependency> </dependencies>
1.3.2：测试excel项目
项目名：zx-test-excel
修改pom，添加依赖
<dependencies> <dependency> <groupId>com.alibaba</groupId> <artifactId>easyexcel</artifactId> <version>3.1.1</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency> </dependencies>
1.4：基本操作
1.4.1：测试JavaBean
常用的注解：
@Data
@AllArgsConstructor
@NoArgsConstructor
@ColumnWidth(30)
@HeadRowHeight(30)
public class Student1 {
@ExcelProperty("编号")
private String id;
@ExcelProperty("姓名")
@ContentFontStyle(fontName = "楷体",italic = BooleanEnum.TRUE,color = Font.ITALIC)
private String name;
@ExcelProperty({"基本信息","年龄"})
private Integer age;
@ExcelProperty({"基本信息","电话"})
private String phone;
@ExcelProperty({"可选信息","邮件"})
private String Email;
@ExcelProperty({"可选信息","生日"})
@DateTimeFormat("yyyy-MM-dd HH:mm")
private Date birthday;
}1.4.2：测试文件路径
public String path(){
return this.getClass().getResource("/").getPath();
}1.4.3：写入操作
-
excel 属于 office组件一个软件
-
存在若干版本，大体上划分2种情况，2007前的，2007年后的
-
2003版：扩展名 xls，内容比较少，最大单元格
IV65536，256列(IV) -
2007版：扩展名 xlsx，内容较多，最大单元格
XFD1048576，16384列(XFD)
-
// 模拟数据
public List<Student1> getDate(){
//模拟十条数据
ArrayList<Student1> student1s = new ArrayList<>();
for (int i = 0; i < 10; i++) {
Student1 student1 = new Student1(i+"","土豆"+i,i,"115"+i,"626"+i,new Date());
student1s.add(student1);
}
return student1s;
}
//创建测试写程序
@Test
public void testWrite(){
//写入位置：%classpath%/
//文件名称：student-demo.xls
//表名：土豆
//1,文件位置
String file = path()+"student_demo1.xls";
//2 写操作
EasyExcel.write(file, Student1.class).sheet("土豆").doWrite(getDate());
}1.4.4：读出操作
处理类：
-
处理类需要实现
AnalysisEventListener接口
package com.czxy.read;
import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.czxy.excel.Student1;
public class StudentDataListener1 extends AnalysisEventListener<Student1> {
@Override
public void invoke(Student1 student1, AnalysisContext analysisContext) {
System.out.println(student1);
}
@Override
public void doAfterAllAnalysed(AnalysisContext analysisContext) {
}
}
//测试读出excel程序
@Test
public void testRead(){
String file = path()+"student_demo1.xls";
//读操作
EasyExcel.read(file, Student1.class, new StudentDataListener1()).sheet("土豆").doRead();
}1.5：复杂操作
1.5.1：复合表头
package com.czxy.excel;
import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.annotation.format.DateTimeFormat;
import com.alibaba.excel.annotation.write.style.ColumnWidth;
import com.alibaba.excel.annotation.write.style.ContentFontStyle;
import com.alibaba.excel.annotation.write.style.HeadRowHeight;
import com.alibaba.excel.enums.BooleanEnum;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.awt.*;
import java.util.Date;
@Data
@AllArgsConstructor
@NoArgsConstructor
@ColumnWidth(30)
@HeadRowHeight(30)
public class Student2 {
@ExcelProperty("编号")
private String id;
@ExcelProperty("姓名")
@ContentFontStyle(fontName = "楷体",italic = BooleanEnum.TRUE,color = Font.ITALIC)
private String name;
@ExcelProperty({"基本信息","年龄"})
private Integer age;
@ExcelProperty({"基本信息","电话"})
private String phone;
@ExcelProperty({"可选信息","邮件"})
private String Email;
@ExcelProperty({"可选信息","生日"})
@DateTimeFormat("yyyy-MM-dd HH:mm")
private Date birthday;
}
1.5.2：写操作：多表
//得到根目录路径
public String path(){
return this.getClass().getResource("/").getPath();
}
// 模拟数据
public List<Student1> getDate(){
//模拟十条数据
ArrayList<Student1> student1s = new ArrayList<>();
for (int i = 0; i < 10; i++) {
Student1 student1 = new Student1(i+"","土豆"+i,i,"115"+i,"626"+i,new Date());
student1s.add(student1);
}
return student1s;
}
//创建测试书写多表
@Test
public void testWrite(){
//写入位置：%classpath%/
//文件名称：student-demo.xls
//表名：土豆
//1,文件位置
String file = path()+"student_demo2.xls";
//2 写操作
ExcelWriter excelWriter = EasyExcel.write(file, Student2.class).build();
//写入多个sheet
WriteSheet writeSheet1 = EasyExcel.writerSheet("爱吃豆的").build();
excelWriter.write(getDate(),writeSheet1);
//写入第二个sheet
WriteSheet writeSheet2 = EasyExcel.writerSheet("土豆").build();
excelWriter.write(getDate(),writeSheet2);
excelWriter.finish();
}1.5.3：读操作：多表
具有缓存处理类
package com.czxy.read;
import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.czxy.excel.Student2;
import java.util.ArrayList;
import java.util.List;
public class StudentDataListener2 extends AnalysisEventListener<Student2> {
//创建一个集合用于保存学生
private List<Student2> student2List = new ArrayList<>();
//创建一个变量用于判断
private Integer size = 4;
@Override
public void invoke(Student2 student2, AnalysisContext analysisContext) {
student2List.add(student2);
if (student2List.size()>size){
print();
}
}
//重新创建一个方法
public void print(){
student2List.forEach(System.out::println);
System.out.println("============");
//打印完成之后进行清空集合
student2List.clear();
}
//该方法
@Override
public void doAfterAllAnalysed(AnalysisContext analysisContext) {
System.out.println("打印完成");
//如果集合中还有数据进行打印
if (!student2List.isEmpty()){
print();
}
student2List.clear();
}
}
读操作
@Test
public void testRead(){
String file = path()+"student_demo2.xls";
//读操作
ExcelReader excelReader = EasyExcel.read(file, Student2.class, new StudentDataListener2()).build();
ReadSheet readSheet1 = EasyExcel.readSheet("爱吃豆的").build();
excelReader.read(readSheet1);
ReadSheet readSheet2 = EasyExcel.readSheet("土豆").build();
excelReader.read(readSheet2);
excelReader.finish();
}1.5.4：写操作：多对象
Student
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Student {
@ExcelProperty("姓名")
private String name;
@ExcelProperty("年龄")
private Integer age;
}Book
@Data
@NoArgsConstructor
@AllArgsConstructor
@HeadRowHeight(50)
@HeadFontStyle(fontName = "黑体",italic = BooleanEnum.TRUE, color = Font.COLOR_RED, underline = 2)
public class Book {
@ExcelProperty("编号")
private String id;
@ExcelProperty({"作者信息","姓名"})
private String authorName;
@ExcelProperty({"作者信息","年龄"})
private Integer authorAge;
@ExcelProperty({"书籍基本信息","标题"})
private String title;
@ContentFontStyle(fontName = "楷书",italic = BooleanEnum.TRUE, color = Font.COLOR_RED, underline = -1)
@ExcelProperty({"书籍基本信息","价格"})
private Double price;
@ExcelProperty({"书籍基本信息","出版日期"})
@DateTimeFormat("yyyy年MM月dd日")
private Date publishDate;
}实现
public class TestManyObject {
// 获得当前项目的运行时的根目录
public String getPath() {
return this.getClass().getResource("/").getPath();
}
// 模拟数据
public List<Student> getStudentData() {
List<Student> list = new ArrayList<>();
for (int i = 0; i < 20; i++) {
list.add(new Student("张三" + i, 18 + i));
}
return list;
}
public List<Book> getBookData() {
List<Book> list = new ArrayList<>();
for (int i = 0; i < 20; i++) {
list.add(new Book(i+"" , "张三" + i , 18 +i, "坏蛋是怎么"+i, 998d+i, new Date()));
}
return list;
}
// 遍历map即可
private Map<Class<?>, List<?>> getData() {
Map<Class<?>, List<?>> map = new HashMap<>();
map.put(Student.class, getStudentData());
map.put(Book.class, getBookData());
return map;
}
@Test
public void testManyObject() {
String file = getPath() + "many_object.xlsx";
//1 开始写
ExcelWriter excelWriter = EasyExcel.write(file).build();
//2 依次写每一个对象
for(Map.Entry<Class<?>, List<?>> entry : getData().entrySet()) {
Class<?> clazz = entry.getKey(); //类型
List<?> data = entry.getValue(); //数据
WriteSheet writeSheet = EasyExcel.writerSheet(clazz.getSimpleName()).head(clazz).build();
excelWriter.write(data, writeSheet);
}
//3 写完成
excelWriter.finish();
}
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