SpringBoot整合EasyExcel的完整过程记录
easyexcel是阿里巴巴旗下开源项目,主要用于Excel文件的导入和导出处理,下面这篇文章主要给大家介绍了关于SpringBoot整合EasyExcel的完整过程,需要的朋友可以参考下
目录
为什么要用EasyExcel
1.EasyExcel简介
2.使用EasyExcel实现写
2.1 创建实体类
2.2 测试写Excel
3.使用EasyExcel实现读
3.1 创建读取操作的监听器
3.2 测试读Excel
4.springboot项目实践EasyExcel
4.1 pom中引入相关依赖
4.2 创建数据库表及添加数据
4.3 实体类
4.4 Controller层
4.5 Service层
4.6 创建监听器(核心部分)
4.7 结果展示
总结
为什么要用EasyExcel
由于apache poi和jxl,excelPOI都有一个严重的问题,就是非常消耗内存,特别处理数据量多时,速度慢并且时有异常发生,所以改用由阿里研发的easyExcel更可靠一些,它的官方建议对于1000行以内的采用原来poi的写法一次读写,但于1000行以上的数据,有用了一行行进行解析的方案,这样避免了内存的溢出。
1.EasyExcel简介
Java领域解析、生成Excel比较有名的框架有Apache poi、jxl等。但他们都存在一个严重的问题就是非常的耗内存。如果你的系统并发量不大的话可能还行,但是一旦并发上来后一定会OOM或 者JVM频繁的full gc。
EasyExcel是阿里巴巴开源的一个excel处理框架,以使用简单、节省内存著称。EasyExcel能大大减少占用内存的主要原因是在解析Excel时没有将文件数据一次性全部加载到内存中,而是从磁盘上一 行行读取数据,逐个解析。
EasyExcel采用一行一行的解析模式,并将一行的解析结果以观察者的模式通知处理 (AnalysisEventListener)
2.使用EasyExcel实现写
2.1 创建实体类
创建与Excel对应的实体类
1 2 3 4 5 6 7 8 9 10 11 12 13 | /** * @author xppll * @date 2021/12/3 10:05 */ @Data public class DemoData { //设置excel表头名称,index表示对应的第几列 @ExcelProperty (value = "学生编号" ,index = 0 ) private Integer sno; @ExcelProperty (value = "学生姓名" ,index = 1 ) private String sname; } |
ExcelProperty:指定当前字段对应excel中的那一列。可以根据名字或者Index去匹配。当然也可以不写,默认第一个字段就是index=0,以此类推。
2.2 测试写Excel
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | /** * @author xppll * @date 2021/12/3 10:08 */ public class TestWriteExcel { public static void main(String[] args) { //实现excel写的操作 //1.设置写入文件夹的地址和excel文件名称 String fileName = "D:\\write.xlsx" ; //2.调用easyexcel里面方法实现写操作 //传入:文件存放的路径+对应的实体类class EasyExcel.write(fileName, DemoData. class ).sheet( "学生列表" ).doWrite(getData()); } //创建方法返回list集合(测试数据) private static List<DemoData> getData() { List<DemoData> list = new ArrayList<>(); for ( int i = 0 ; i < 10 ; i++) { DemoData data = new DemoData(); data.setSno(i); data.setSname( "lucy" + i); list.add(data); } return list; } } |
结果如下
3.使用EasyExcel实现读
3.1 创建读取操作的监听器
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | /** * @author xppll * @date 2021/12/3 10:29 */ public class ExcelListener extends AnalysisEventListener<DemoData> { /** * 一行一行读取Excel中的内容 * * @param data * @param analysisContext */ @Override public void invoke(DemoData data, AnalysisContext analysisContext) { System.out.println( "****" + data); } /** * 读取表头 * @param headMap * @param context */ @Override public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) { System.out.println( "表头:" +headMap); } /** * 读取完成之后做的事 * * @param analysisContext */ @Override public void doAfterAllAnalysed(AnalysisContext analysisContext) { } } |
3.2 测试读Excel
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | /** * @author xppll * @date 2021/12/3 10:35 */ public class TestReadExcel { public static void main(String[] args) { //读取文件的路径 String fileName = "D:\\write.xlsx" ; //传入三个参数:文件路径+封装的类的class+监听器 EasyExcel.read(fileName, DemoData. class , new ExcelListener()) .sheet() .doRead(); } } |
控制台输出如下
4.springboot项目实践EasyExcel
通过在后台管理上传excel文件添加课程分类(一共两级分类)
4.1 pom中引入相关依赖
1 2 3 4 5 | < dependency > < groupId >com.alibaba</ groupId > < artifactId >easyexcel</ artifactId > < version >3.0.5</ version > </ dependency > |
4.2 创建数据库表及添加数据
这里创建一个课程表用EasyExcel实现课程的分类
1 2 3 4 5 6 7 8 9 10 | CREATE TABLE `edu_subject` ( `id` char (19) NOT NULL COMMENT '课程类别ID' , `title` varchar (10) NOT NULL COMMENT '类别名称' , `parent_id` char (19) NOT NULL DEFAULT '0' COMMENT '父ID' , `sort` int (10) unsigned NOT NULL DEFAULT '0' COMMENT '排序字段' , `gmt_create` datetime NOT NULL COMMENT '创建时间' , `gmt_modified` datetime NOT NULL COMMENT '更新时间' , PRIMARY KEY (`id`), KEY `idx_parent_id` (`parent_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=COMPACT COMMENT= '课程科目' ; |
1 | INSERT INTO `edu_subject` VALUES ( '1178214681118568449' , '后端开发' , '0' ,1, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681139539969' , 'Java' , '1178214681118568449' ,1, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681181483010' , '前端开发' , '0' ,3, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681210843137' , 'JavaScript' , '1178214681181483010' ,4, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681231814658' , '云计算' , '0' ,5, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681252786178' , 'Docker' , '1178214681231814658' ,5, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681294729217' , 'Linux' , '1178214681231814658' ,6, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681324089345' , '系统/运维' , '0' ,7, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681353449473' , 'Linux' , '1178214681324089345' ,7, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681382809602' , 'Windows' , '1178214681324089345' ,8, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681399586817' , '数据库' , '0' ,9, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681428946945' , 'MySQL' , '1178214681399586817' ,9, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681454112770' , 'MongoDB' , '1178214681399586817' ,10, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681483472898' , '大数据' , '0' ,11, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681504444418' , 'Hadoop' , '1178214681483472898' ,11, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681529610242' , 'Spark' , '1178214681483472898' ,12, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681554776066' , '人工智能' , '0' ,13, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681584136193' , 'Python' , '1178214681554776066' ,13, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681613496321' , '编程语言' , '0' ,14, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178214681626079234' , 'Java' , '1178214681613496321' ,14, '2019-09-29 15:47:25' , '2019-09-29 15:47:25' ),( '1178585108407984130' , 'Python' , '1178214681118568449' ,2, '2019-09-30 16:19:22' , '2019-09-30 16:19:22' ),( '1178585108454121473' , 'HTML/CSS' , '1178214681181483010' ,3, '2019-09-30 16:19:22' , '2019-09-30 16:19:22' ); |
4.3 实体类
1 2 3 4 5 6 7 | @Data public class SubjectData { @ExcelProperty (index = 0 ) private String oneSubjectName; @ExcelProperty (index = 1 ) private String twoSubjectName; } |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | /** * 课程科目 * @author xppll * @since 2021-12-03 */ @Data @EqualsAndHashCode (callSuper = false ) @Accessors (chain = true ) @ApiModel (value= "EduSubject对象" , description= "课程科目" ) public class EduSubject implements Serializable { private static final long serialVersionUID = 1L; @ApiModelProperty (value = "课程类别ID" ) @TableId (value = "id" , type = IdType.ID_WORKER_STR) private String id; @ApiModelProperty (value = "类别名称" ) private String title; @ApiModelProperty (value = "父ID" ) private String parentId; @ApiModelProperty (value = "排序字段" ) private Integer sort; @ApiModelProperty (value = "创建时间" ) @TableField (fill = FieldFill.INSERT) private Date gmtCreate; @ApiModelProperty (value = "更新时间" ) @TableField (fill = FieldFill.INSERT_UPDATE) private Date gmtModified; } |
4.4 Controller层
1 2 3 4 5 6 7 8 9 10 11 | @Autowired private EduSubjectService subjectService; //添加课程分类 //获取前端上传过来的excel文件,把文件内容读取出来保存到数据库 @PostMapping ( "addSubject" ) public R addSubject(MultipartFile file){ subjectService.saveSubject(file,subjectService); return R.ok(); } |
4.5 Service层
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | //添加课程分类 @Override public void saveSubject(MultipartFile file, EduSubjectService subjectService) { try { //得到文件的输入流 InputStream in = file.getInputStream(); //调用方法进行读取 EasyExcel.read(in, SubjectData. class , new SubjectExcelListener(subjectService)).sheet().doRead(); } catch (Exception e) { e.printStackTrace(); } } |
4.6 创建监听器(核心部分)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 | /** * @author xppll * @date 2021/12/3 12:02 */ @Component public class SubjectExcelListener extends AnalysisEventListener<SubjectData> { public EduSubjectService subjectService; public SubjectExcelListener(EduSubjectService subjectService) { this .subjectService = subjectService; } public SubjectExcelListener() { } //读取excel内容,一行一行读取 @Override public void invoke(SubjectData subjectData, AnalysisContext analysisContext) { if (subjectData == null ) { throw new GuliException( 20001 , "文件数据为空" ); } //一行一行读取,第一个值为一级分类,第二个值为二级分类 //先判断一级分类是否重复 EduSubject existOneSubject = this .existOneSubject(subjectData.getOneSubjectName(), subjectService); //没有相同的一级分类 if (existOneSubject== null ){ existOneSubject= new EduSubject(); existOneSubject.setParentId( "0" ); existOneSubject.setTitle(subjectData.getOneSubjectName()); subjectService.save(existOneSubject); } //获取一级分类的id值 String pid=existOneSubject.getId(); //判断二级分类是否重复 EduSubject existTwoSubject = this .existTwoSubject(subjectData.getTwoSubjectName(), subjectService, pid); if (existTwoSubject== null ){ existTwoSubject= new EduSubject(); existTwoSubject.setParentId(pid); existTwoSubject.setTitle(subjectData.getTwoSubjectName()); subjectService.save(existTwoSubject); } } //判断一级分类不能重复添加 private EduSubject existOneSubject(String name, EduSubjectService subjectService) { LambdaQueryWrapper<EduSubject> queryWrapper = new LambdaQueryWrapper<>(); queryWrapper.eq(EduSubject::getTitle, name) .eq(EduSubject::getParentId, "0" ); EduSubject oneSubject = subjectService.getOne(queryWrapper); return oneSubject; } //判断二级分类不能重复添加 private EduSubject existTwoSubject(String name, EduSubjectService subjectService,String pid) { LambdaQueryWrapper<EduSubject> queryWrapper = new LambdaQueryWrapper<>(); queryWrapper.eq(EduSubject::getTitle, name) .eq(EduSubject::getParentId, pid); EduSubject twoSubject = subjectService.getOne(queryWrapper); return twoSubject; } @Override public void doAfterAllAnalysed(AnalysisContext analysisContext) { } } |
4.7 结果展示
Excel模板如下
上传后数据库数据如下
如果想要详细使用可以参考官方文档:EasyExcel
总结
到此这篇关于SpringBoot整合EasyExcel的文章就介绍到这了
原文链接:https://blog.csdn.net/qq_45966440/article/details/121723600