The technical principle of the "Streaming Excel Reader" framework in the Java class library
The technical principles of the "Streaming Excel Reader" framework in the Java Class Library
Streaming Excel Reader is a Java library for handling large excel files.It reads Excel files in a streamlined manner and provides efficient reading ability. It is particularly suitable for handling large Excel files greater than memory limit.
The technical principles of Streaming Excel Reader can be divided into the following aspects:
1. Event -based parster: Streaming Excel Reader uses event -driven parser to parse the Excel file.The parser reads each part of the Excel file in the order of the event, instead of loading the entire file to the memory at one time.This mechanism can greatly reduce the amount of memory and improve the reading speed.
2. XMLBEANS data mapping: Streaming Excel Reader uses XMLBEANS technology in Apache Poi to map data in the Excel file.XMLBEANS is a Java data binding tool based on XML Schema. It can generate the Java class according to the specified XML SCHEMA to read and operate XML data.Streaming Excel Reader uses XMLBEANS to dynamically generate and load the data structure of the Excel file to process and store data in the parsing process.
3. Streaming processing: Streaming Excel Reader processing the content of the excel file according to the line.It reads each line of data from the Excel file and converts it into a Java object or data structure for processing.This stream processing mechanism allows Streaming Excel Reader to read Excel files one by one without loading the entire file into memory to save memory space.
Below is a sample code for reading the excel file with Streaming Excel Reader:
import com.monitorjbl.xlsx.StreamingReader;
import com.monitorjbl.xlsx.impl.StreamingCell;
import com.monitorjbl.xlsx.impl.StreamingRow;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
public class ExcelReaderExample {
public static void main(String[] args) throws IOException {
File file = new File("example.xlsx");
InputStream inputStream = new FileInputStream(file);
try (StreamingReader reader = StreamingReader.builder()
.Rowcachesize (100) // Cache line number
.buffersize (4096) // Cushion size
.open(inputStream)) {
for (StreamingRow row : reader) {
for (StreamingCell cell : row) {
System.out.println(cell.getStringCellValue());
}
}
}
}
}
In the above sample code, we use Streaming Excel Reader to read all cell data in the Excel file named "Example.xlsx".By constructing the StreamingReader object and specifying the appropriate cavity and the size of the buffer area, we can read and output the data in the Excel file in a streaming manner.
In summary, Streaming Excel Reader has realized the function of highly read large Excel files through technical principles such as event -driven parsers, XMLBEANS data mapping and streaming processing.It can reduce the amount of memory, improve the read speed, and apply to handle large Excel files beyond the memory limit.
