Camel: How to read and analyze CSV files
How to read and analyze CSV files
CSV (comma division value) is a commonly used file format for data exchange between electronic tables and databases.In Java, we can use some libraries to read and analyze CSV files.This article will introduce how to use the OpenCSV library and Apache Commons CSV library to achieve this goal.
Use OpenCSV library to read and analyze CSV files
Step 1: Add the dependencies of the OpenCSV library
First, you need to add an opencsv library to your project.You can add the following dependencies in Maven or Gradle configuration files:
Maven:
<dependency>
<groupId>com.opencsv</groupId>
<artifactId>opencsv</artifactId>
<version>5.5.2</version>
</dependency>
Gradle:
groovy
implementation 'com.opencsv:opencsv:5.5.2'
Step 2: Read the CSV file
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("path/to/your/csv/file.csv"))) {
String[] nextLine;
while ((nextLine = reader.readNext()) != null) {
for (String value : nextLine) {
// Treat each value per value
System.out.print(value + ", ");
}
System.out.println();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
In the above example, we use the CSVReader class to read each line of data from the CSV file.The Readnext () method returns a String array, and each element in the string array corresponds to a value in the CSV file.
Use Apache Commons CSV to read and analyze CSV files
Step 1: Add the dependencies of Apache Commons CSV library
First, you need to add Apache Commons CSV libraries to your project.You can add the following dependencies in Maven or Gradle configuration files:
Maven:
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-csv</artifactId>
<version>1.8</version>
</dependency>
Gradle:
groovy
implementation 'org.apache.commons:commons-csv:1.8'
Step 2: Read the CSV file
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVRecord;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
public class CSVParserExample {
public static void main(String[] args) {
try (Reader reader = new FileReader("path/to/your/csv/file.csv");
CSVParser csvParser = new CSVParser(reader, CSVFormat.DEFAULT)) {
for (CSVRecord csvRecord : csvParser) {
for (String value : csvRecord) {
// Treat each value per value
System.out.print(value + ", ");
}
System.out.println();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
In the above example, we use the CSVPARSER class to analyze the CSV file.The CSVRecord object represents a line of data in the CSV file, and we can access each value by iteration.
This is the basic steps to read and analyze the CSV files using the OpenCSV library and Apache Commons CSV library.You can further process the data after your own needs.
