Use the "CSV" framework to process big data in the Java library
Use CSV framework to process big data in the Java library
Overview:
In modern data processing, the large data volume CSV (comma separation value) file has become one of the very common data formats.In Java development, we often need to process a large amount of CSV file data and perform various operations and analysis.To facilitate and efficiently handle these large data CSV files, we can use the CSV framework provided in the Java class library.This article will introduce how to use the CSV framework in Java to process the large data volume of CSV files and provide the corresponding Java code example.
Introduction to the CSV framework:
In the Java class library, there are multiple popular CSV frameworks to choose from, such as: OpenCSV, Apache Commons CSV, Super CSV, etc.These frameworks provide a series of powerful APIs that can be used to read, write and operate data in the CSV file.These frameworks can process a large amount of data and provide some advanced features, such as processing nested data structures, processing data containing quotes and rotary symbols.
Use the CSV framework to read the CSV file:
The following is a simple example of reading CSV files using the OpenCSV framework:
import com.opencsv.CSVReader;
import java.io.FileReader;
import java.io.IOException;
public class CSVReaderExample {
public static void main(String[] args) {
try (CSVReader reader = new CSVReader(new FileReader("data.csv"))) {
String[] nextLine;
while ((nextLine = reader.readNext()) != null) {
// Process each line of data
for (String data : nextLine) {
System.out.print(data + ",");
}
System.out.println();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
In the above example, we use the `csvreader` class provided by the OpenCSV framework to read the CSV file named" data.csv ".Read each line of data by cycle and use the comma to separate.Finally, print the data of each line to the console.
Use the CSV framework to write to the CSV file:
Below is a simple example of writing the CSV file using the Super CSV framework:
import org.supercsv.io.CsvListWriter;
import org.supercsv.io.ICsvListWriter;
import org.supercsv.prefs.CsvPreference;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
public class CSVWriterExample {
public static void main(String[] args) {
try (ICsvListWriter writer = new CsvListWriter(new FileWriter("output.csv"),
CsvPreference.STANDARD_PREFERENCE)) {
List<String> data = new ArrayList<>();
data.add("John Smith");
data.add("25");
data.add("USA");
writer.write(data);
} catch (IOException e) {
e.printStackTrace();
}
}
}
In the above example, we use the `csvlistWriter` class provided by the Super CSV framework to write the CSV file.First instance a `CSVListWriter` object, specify the CSV file and CSV premiere to be written.Then pass each line of data as a list object to the `write () method, which writes the data into the CSV file.
in conclusion:
By using the CSV framework in the Java class library, we can easily handle large data CSV files.Regardless of the data in the CSV file, or writing data to the CSV file, these framework provides a powerful and easy -to -use API to meet our needs for large data CSV file processing.I hope the examples provided in this article can help you.
