Ali open source (easyexcel)

Alibaba open source （EasyExcel）

1. Official website and introduction

1.GitHub Official website

GitHub Address ：https://github.com/alibaba/easyexcel

Use document address https://alibaba-easyexcel.github.io/index.html

2. Introduce

EasyExcel Alibaba is an open source excel Processing framework , To make it easy to use 、 Famous for saving memory .Java Domain analysis 、 Generate Excel Well known frameworks are Apache poi、jxl etc. . But they all have a serious problem that is very memory consuming . If your system has a small amount of concurrency, it may be OK , But once concurrency comes up, it will OOM perhaps JVM Frequent full gc.easyExcel The main reason that can greatly reduce the memory occupation is parsing Excel The file data is not loaded into memory at one time , Instead, read data from a row on the disk , One by one .

2.easyexcel Use

1. stay pom.xml Add dependency in

    <!-- easyexcel start -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>easyexcel</artifactId>
      <version>2.1.6</version>
    </dependency>
    <!-- easyexcel end -->

2.ExcelListener( Call... On import )

Use EasyExcel, You need to create a listening class and inherit AnalysisEventListener

public class CheliangListener extends AnalysisEventListener {
    
	// This value can be obtained through an instance 
	private List<Object> datas = new ArrayList<Object>();
	public void invoke(Object o, AnalysisContext analysisContext) {
    
		datas.add(o);// Data stored in list, For batch processing , Or follow up their own business logic processing .
		doSomething(o);// According to their own business to deal with 
	}

	private void doSomething(Object object) {
    
		//1、 Warehousing call interface 
	}

	public List<Object> getDatas() {
    
		return datas;
	}

	public void setDatas(List<Object> datas) {
    
		this.datas = datas;
	}

	public void doAfterAllAnalysed(AnalysisContext analysisContext) {
    
		// datas.clear();// End of parsing destroy unused resources 
	}
}

PS： among , invoke() and doAfterAllAnalysed() Is a method that must be implemented .

stay invoke() in , We encapsulate the data into list in , In the controller , adopt getter() Method to get data , So we can get easyexcel Help us parse the data , Then type the data , such , We can write data .

3. Create entity class

This is an entity class . We export Excel when , Sometimes a header is required , If you need a header field , We can add... To the corresponding entity class @ExcelProperty(value = "id", index = 0) , @ExcelIgnore By default, all fields will be associated with excel To match , This annotation will ignore this field , And inheritance BaseRowModel. among value On behalf of exporting Excel when , The header name corresponding to this field ;index Represents the header position corresponding to the field .

public class BdCheliangEntity extends BaseRowModel implements Serializable {
    
	/** Primary key */
	@ExcelIgnore
	private String id;
	/** Creator name */
	@ExcelIgnore
	private String createName;
	/** Creator login name */
	@ExcelIgnore
	private String createBy;
	/** Date of creation */
	@ExcelIgnore
	private Date createDate;
	/** Updated by */
	@ExcelIgnore
	private String updateName;
	/** Updater login name */
	@ExcelIgnore
	private String updateBy;
	/** Updated date */
	@ExcelIgnore
	private Date updateDate;
	/** Department */
	@ExcelIgnore
	private String sysOrgCode;
	/** Company */
	@ExcelIgnore
	private String sysCompanyCode;
	/** Process status */
	@ExcelIgnore
	private String bpmStatus;
	/** license plate number */
	@ExcelProperty(value=" license plate number ",index=0)
	private String chepaihao;
	/** models */
	@ExcelProperty(value=" models ",index=1)
	private String chexing;
	/** Maximum volume */
	@ExcelProperty(value=" Maximum volume ",index=2)
	private String zuidatiji;
	/** load */
	@ExcelProperty(value=" load ",index=3)
	private String zaizhong;
	/** Carrying capacity */
	@ExcelProperty(value=" Carrying capacity ",index=4)
	private String zairen;
	/** Leave your driver's license */
	@ExcelProperty(value=" Leave your driver's license ",index=5)
	private String jiazhao;
	/** Is it available */
	@ExcelProperty(value=" Is it available ",index=6)
	private String zhuangtai;
	/** remarks */
	@ExcelProperty(value=" remarks ",index=7)
	private String beizhu;
	/** Default driver */
	@ExcelProperty(value=" Default driver ",index=8)
	private String username;
	/**gps*/
	@ExcelProperty(value="gps",index=9)
	private String gpsid;
	@ExcelProperty(value=" Area ",index=10)
	private String quyu;

	// Query criteria 
	@ExcelIgnore
	private Integer page = 1;
	@ExcelIgnore
	private Integer rows = 10;
	@ExcelIgnore
	private Integer pagerows;
	@ExcelIgnore
	private String searchKey;
	@ExcelIgnore
	private String searchKey2;
	@ExcelIgnore
	private String searchKey3;

4.easyexcel Use of export

controller layer

step ：

1. Add response header information ;
2. add to ExcelWriter;
3. add to Sheet（ Forms ）;
4. Add data ;
5. Output .

  //  export 
	@ResponseBody
	@RequestMapping("/exportExcel")
	public String exporExcel(BdCheliangEntity bdCheliangEntity, HttpServletResponse response) throws IOException {
    
		String result = null;
		ExcelWriter writer = null;
		OutputStream outputStream = response.getOutputStream();
		try {
    
			String fileName =" Vehicle information .xls";
			// Add response header information 
			response.setHeader("Content-disposition", "attachment; filename=" +  URLEncoder.encode(fileName,"UTF-8"));
			response.setContentType("application/msexcel;charset=UTF-8");// Set type 
			response.setHeader("Pragma", "No-cache");// Set head 
			response.setHeader("Cache-Control", "no-cache");// Set head 
			response.setDateHeader("Expires", 0);// Set date header 

			// Instantiation  ExcelWriter
			writer = new ExcelWriter(outputStream, ExcelTypeEnum.XLS, true);

			// Instantiate the form 
			Sheet sheet = new Sheet(1, 0, BdCheliangEntity.class);
			sheet.setSheetName(" Vehicle information ");

			// get data 
			List<BdCheliangEntity> list = bdCheliangService.outExcel(bdCheliangEntity);

			// Output 
			writer.write(list, sheet);
			writer.finish();

			outputStream.flush();
			outputStream.close();
			result = "success";
		} catch (IOException e) {
    
			e.printStackTrace();
			result = "fail";
		} finally {
    
			try {
    
				response.getOutputStream().close();
			} catch (IOException e) {
    
				e.printStackTrace();
			}

		}
		return result;
	}

service layer

@Override
public List<BdCheliangEntity> outExcel(BdCheliangEntity bdCheliangEntity) {
    
   List<BdCheliangEntity> list=bdCheliangMapper.outExcel(bdCheliangEntity);
    return list;
  }

dao layer

List<BdCheliangEntity> outExcel(BdCheliangEntity query);

5.easyexcel Use of import

controller layer

//  Import 
	@RequestMapping("/importExcel")
	@ResponseBody
	public String importExcel(MultipartFile uploadFile) {
    
		String result = null;
		InputStream is = null;
		try {
    
			String filename = uploadFile.getOriginalFilename();
			if (filename != null && (filename.toLowerCase().endsWith(".xls") || filename.toLowerCase().endsWith(".xlsx"))) {
    
				is = new BufferedInputStream(uploadFile.getInputStream());
			} else {
    
				return " The imported file is not excel file ";
			}
			result = bdCheliangService.readExcel(is);
		} catch (Exception e) {
    
			e.printStackTrace();
			return " System error ";
		} finally {
    
			if (is != null) {
    
				try {
    
					is.close();
				} catch (IOException e) {
    
					e.printStackTrace();
				}
			}
		}
		return result;

	}

service layer

step ：

1. Instantiation ExcelListener;
2. Instantiation ExcelReader;
3. Read table information ;
4. Insert data into the database

//  Import 
    @Override
    public String readExcel(InputStream is) {
    
        IdWorker idWorker=new IdWorker(0,0);
          ExcelReader excelReader = null;
            CheliangListener listener = new CheliangListener();
            // excelReader = new ExcelReader(is, ExcelTypeEnum.XLSX, null, listener);
               excelReader = EasyExcelFactory.getReader(is, listener);
                excelReader.read(new Sheet(1, 1, BdCheliangEntity.class));

          List<Object> importList = listener.getDatas();
          List<BdCheliangEntity> list = new ArrayList<>();

        BdCheliangEntity info = new BdCheliangEntity();

        // Convert data type , And insert it into the database 
        for (int i = 0; i < importList.size(); i++) {
    
            info = (BdCheliangEntity) importList.get(i);
            String id = String.valueOf(idWorker.nextId());
            info.setId(id);
            info.setCreateDate(new Date());
            list.add(info);

        }
        if(list.size()>=1) {
    
            bdCheliangMapper.importExcel(list);
            list.clear();
        }


        return "success";
    }

dao layer

 void importExcel(List<BdCheliangEntity> list);

6. effect

export excel effect ：

Front end interface effect ：

Please check the source code for the specific code

3. Source code address

https://gitee.com/lin8081/LWH05