"Streaming Excel Reader" framework technical principles in the Java class library
"Analysis of the Technical Principles of" Streaming Excel Reader in Java Library "
Overview
In Java development, processing Excel files is a very common task.However, because Excel files usually have a large amount of data and complex structures, using traditional reading methods often lead to problems such as memory overflow or performance decline.To solve these problems, we can use the "Streaming Excel Reader" framework to achieve efficient Excel files.
Introduction to Streaming Excel Reader framework
Streaming Excel Reader is a Java class library that specializes in the design of large Excel files.It is based on the Apache Poi library. It uses a streaming process to read large Excel files efficiently, reducing memory consumption and improving reading performance.Compared to the traditional way of reading, Streaming Excel Reader does not need to load the entire Excel file into the memory. Instead, it only needs to process the current line data by reading.This way of reading makes Streaming Excel Reader perform well when processing large excel files.
Principle of Streaming Excel Reader framework
The implementation principles of the Streaming Excel Reader framework are mainly divided into the following steps:
1. Open Excel file:
Using Streaming Excel Reader, we first need to open the Excel file to be read.By calling the corresponding API, you can open an excel file with a specified path.
2. Select the sheet you want to read:
Excel files are usually composed of multiple sheets.Using Streaming Excel Reader, we can choose a specific sheet we want to read as needed to read the data we care about.This can avoid the overhead of the entire Excel file.
3. Read the data one by one:
Through Streaming Excel Reader, we can gradually read the data in the Excel file according to the line.After reading a line of data, we can obtain the values of each cell in the line through the API and handle it accordingly.
4. Process data:
When processing each line of data, we can use custom logic to operate the data.For example, we can store data in the database, or perform subsequent data analysis and calculations.
For example code
The following is a simple Java example code. Demonstrate how to use Streaming Excel Reader to read the data in the Excel file:
import com.monitorjbl.xlsx.StreamingReader;
import com.monitorjbl.xlsx.impl.StreamingCell;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
public class ExcelReaderExample {
public static void main(String[] args) {
try {
FileInputStream file = new FileInputStream("path/to/excel/file.xlsx");
StreamingReader reader = StreamingReader.builder()
.Rowcachesize (100) // The number of cache lines in memory
.buffersize (4096) //
.opeen (file); // Open the excel file
for (StreamingRow row : reader) {
for (StreamingCell cell : row) {
String cellValue = cell.getStringCellValue();
System.out.print(cellValue + "\t");
}
System.out.println();
}
Reader.close (); // Close the flow
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
In the above example code, we first use the `FileInputStream` to open the Excel file to be read.Then, we use the builter method of the StreamexcelReader class to create a StreamexcelReader instance.By setting Rowcachesize and Buffersize, we can customize the size of the number of rows and data reading of memory cache when reading the size of the buffer.Finally, by traversing lines and columns, we can read the data in the Excel file one by one and processed them accordingly.
in conclusion
The Streaming Excel Reader framework is a powerful and efficient Java class library that can help us avoid memory overflow and performance problems when dealing with large excel files.Through streaming, Streaming Excel Reader can reduce memory consumption, improve reading performance, and use it flexibly and easy to use.When processing large Excel files, we can consider using Streaming Excel Reader to improve our development efficiency and performance.
