COMMONS CSV (SANDBOX) framework technical principles in the Java class library
COMMONS CSV (SANDBOX) framework technical principles in the Java class library
Abstract: This article will introduce the technical principles of the Commons CSV (Sandbox) framework in the Java class library in detail.Commons CSV is an open source library for reading and writing CSV files. By providing a unified interface and convenient method, the operation process of the CSV file is simplified.This article will first introduce the basic concepts and formats of the CSV file, and then analyze the working principle of the COMMONS CSV framework in depth, and display its usage method through the example code.
1. Overview of CSV file
CSV (Comma Separated Values) file is a common text file format that is used to store structured data similar to tables.It is composed of a comma -separated data row, and each data field is separated by a comma.Generally, the first line of the CSV file contains field names, and subsequent lines include field values.The advantages of CSV files are simple, easy to read, and can be imported and exported by common electronic meter software.
2. Commons CSV framework introduction
Commons CSV is an open source project of the Apache Software Foundation, which aims to provide a simple and flexible way to read and write CSV files.Commons CSV provides a unified interface that blocks different types of CSV file implementation details, allowing users to easily read and write CSV files easily.
3. Commons CSV framework working principle
The core of the Commons CSV framework is a CSV parser (CSVPARSER) and a CSV formatr (CSVPrinter).The parser is responsible for reading the data from the CSV file, and the formattor is responsible for writing the data into the CSV file.
a) Analyst (CSVPARSER):
The parser is read data from the CSV file.It analyzes the contents of the CSV file into a record (CSVRecord), and each record is a key value composed of the field name and field value.The parser will process the data separated by the comma and identify the field name.The parser provides a variety of ways to read and process CSV files, such as file -based analysis, Reader -based analysis, etc.
b) Format (CSVPrinter):
The formatr is used to write data into the CSV file.It accepts a collection of records, and then formats it into a data separate data separate data and write it into the CSV file.The formatomer provides a variety of formatting options, such as setting field separators, field quotes, record separators, etc.
4. Commons CSV use examples
Below is a sample code read and write to the CSV file with the Commons CSV framework:
a) CSV file reading example:
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVRecord;
import java.io.FileReader;
import java.io.IOException;
public class CSVReaderExample {
public static void main(String[] args) {
try (CSVParser parser = new CSVParser(new FileReader("data.csv"))) {
for (CSVRecord record : parser) {
String name = record.get("Name");
String age = record.get("Age");
System.out.println("Name: " + name + ", Age: " + age);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
b) CSV file writing example:
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVPrinter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Arrays;
public class CSVWriterExample {
public static void main(String[] args) {
try (CSVPrinter printer = new CSVPrinter(new FileWriter("data.csv"), CSVFormat.DEFAULT)) {
printer.printRecord("Name", "Age");
printer.printRecord("John Doe", 30);
printer.printRecord("Jane Smith", 25);
} catch (IOException e) {
e.printStackTrace();
}
}
}
The above example shows how to read and write the CSV file with the COMMONS CSV framework.Through simple API calls, you can easily implement the operation of CSV files.
Conclusion: This article details the technical principles of the Commons CSV (Sandbox) framework in the Java class library.By the cooperation of parsers and formators, the Commons CSV provides a simple and flexible way to read and write into the CSV file.The sample code shows how to read and write the CSV file with how to use the Commons CSV framework.It is hoped that readers can better understand and apply the Commons CSV framework through the introduction of this article.
