The implementation principle of "Streaming Excel Reader" framework technology in the Java class library

The principle of implementation of "Streaming Excel Reader" framework technology in the Java class library Introduction: In daily development, we often need to process Excel files to read the data. However, when the excel file is very large, reading data in traditional methods may cause problems such as memory spillover.In order to solve this problem, a framework technology called "Streaming Excel Reader" appears in the Java class library.EssenceThis article will introduce the implementation principles of this technology and explain it in Java code examples. 1. Implementation principle The implementation principle of "Streaming Excel Reader" framework technology is mainly through the following steps: 1.1 Analysis of Excel file format: Excel file is stored in a binary format. First, the excel file needs to be parsed into a data structure for subsequent operations.This step is usually used to complete the POI (Poor Obfusion Implementation) library. 1.2 Read the Excel file: After obtaining the data structure, we need to read it by line by line by the structure and data format of the excel file.Because the Excel file is usually relatively large, it is not feasible to read the entire file into the memory. Here we need to use "stream" reading technology.Specifically, some APIs provided by POI can read the content of Excel files one by one, and convert each line of data into an object for follow -up processing. 1.3 Processing Excel data: After reading each line of EXCEL files, it can process business logic, such as saving data into the database, data analysis, generating reports, etc. 1.4 Batch Reading Excel data: In order to improve the efficiency of reading Excel files, the method of reading can be used in batches.That is, a batch of data (such as 1000 lines) each time, processed once, and then continue to read the next batch of data.This circular reading and processing until the data of the entire Excel file is read. 2. Java code example Below is a simple Java code example, demonstrating the basic operation of reading the excel file with the "Streaming Excel Reader" framework technology: import java.io.FileInputStream; import org.apache.poi.ss.usermodel.*; import org.apache.poi.xssf.streaming.*; public class ExcelReaderExample { public static void main(String[] args) throws Exception { FileInputStream file = new FileInputStream("path/to/excel.xlsx"); Workbook workbook = new SXSSFWorkbook(file); Sheet sheet = workbook.getSheetAt(0); for (Row row : sheet) { for (Cell cell : row) { // Process data in each cell switch (cell.getCellType()) { case STRING: System.out.print(cell.getStringCellValue()); break; case NUMERIC: System.out.print(cell.getNumericCellValue()); break; case BOOLEAN: System.out.print(cell.getBooleanCellValue()); break; default: System.out.print(""); } System.out.print("\t"); } System.out.println(); } workbook.close(); file.close(); } } In this example, we use the Apache Poi library and use the SXSSFWORKBOOK class to represent the workbook object.Through SXSSFWORKBOOK, we can make full use of streaming processing technology to read the data of the Excel file.Specifically, we obtain Sheet and ROW objects through the Workbook object, and use dual cycles to traverse each cell data.According to the type of cells, we can take different operations, such as obtaining string values, digital values, or Boolean values. Summary: Through "Streaming Excel Reader" framework technology, we can efficiently read large excel files to avoid problems such as memory overflow.This article introduces the implementation principle of this technology and provides a simple Java code example to illustrate its basic operation.It is hoped that readers can have a certain understanding of the "implementation principle of" Streaming Excel Reader in the Java Class Library "through this article and applies to the actual development process.