Learn about the "CSV" framework and its use in the Java class library
Learn about the "CSV" framework and its use in the Java class library
Overview:
CSV (COMMA-SEPARATED VALUES) is a commonly used text file format for storing and exchange form data.There are multiple CSV frameworks in the Java library to use. These frameworks provide convenient methods to read, write and process CSV files.This article will introduce the CSV framework commonly used in Java, as well as their purpose and example code.
1. Opencsv ：
OpenCSV is a popular Java library for reading and writing CSV files.It provides a simple API for processing CSV data.The following is a sample code that demonstrates how to read and write the CSV file with OpenCSV.
Read the sample code of the CSV file:
import com.opencsv.CSVReader;
try (CSVReader reader = new CSVReader(new FileReader("data.csv"))) {
String[] line;
while ((line = reader.readNext()) != null) {
// Process each line of data in the CSV file
System.out.println(Arrays.toString(line));
}
} catch (IOException e) {
e.printStackTrace();
}
Summary code written to the CSV file:
import com.opencsv.CSVWriter;
try (CSVWriter writer = new CSVWriter(new FileWriter("data.csv"))) {
String[] line1 = {"John", "Doe", "john@example.com"};
String[] line2 = {"Jane", "Smith", "jane@example.com"};
writer.writeNext(line1);
writer.writeNext(line2);
} catch (IOException e) {
e.printStackTrace();
}
2. Apache Commons CSV：
Apache Commons CSV is another popular Java class library that is used to read and write CSV files.It provides a simple API and supports various CSV formats and options.Below is a sample code that demonstrates how to read and write the CSV file with Apache Commons CSV.
Read the sample code of the CSV file:
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVRecord;
try (CSVParser parser = CSVParser.parse(new FileReader("data.csv"), CSVFormat.DEFAULT)) {
for (CSVRecord record : parser) {
// Process each line of data in the CSV file
System.out.println(record);
}
} catch (IOException e) {
e.printStackTrace();
}
Summary code written to the CSV file:
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVPrinter;
try (CSVPrinter printer = new CSVPrinter(new FileWriter("data.csv"), CSVFormat.DEFAULT)) {
printer.printRecord("John", "Doe", "john@example.com");
printer.printRecord("Jane", "Smith", "jane@example.com");
} catch (IOException e) {
e.printStackTrace();
}
in conclusion:
The CSV framework is an important tool for reading, writing and processing CSV files in the Java library.This article introduces two commonly used CSV frameworks-OpenCSV and Apache Commons CSV, and provides example code reading and writing to CSV files.By using these frameworks, developers can easily process data in CSV format and perform corresponding operations and analysis.
