Camel: How to convert CSV data to Java object
How to convert CSV data to Java object
CSV (comma segmental value) is a common data format that is often used to store and exchange data.In Java, we can use various methods to convert CSV data to Java objects.This article will introduce how to use the open source library OpenCSV to implement this function.
1. Download OpenCSV
First, we need to download the OpenCSV library.In the Maven project, we can add the following dependencies to the POM.XML file:
<dependency>
<groupId>com.opencsv</groupId>
<artifactId>opencsv</artifactId>
<version>5.5.1</version>
</dependency>
If you do not use Maven, you can download jar files on OpenCSV's official website and manually import it into the project.
2. Create the Java object class
Before converting CSV data to Java objects, we need to create a corresponding Java class to represent each line of CSV data.Suppose we have a CSV file that contains names and age, which can create a Java class called Person:
public class Person {
private String name;
private int age;
// You must provide a non -ginseng constructor function
public Person() {}
// Create other constructors and getter/setter methods as needed
}
3. Use OpenCSV to analyze CSV data
Using OpenCSV to resolve CSV data is very simple.The following is an example code that reads CSV data and converts each row into Person objects:
import com.opencsv.CSVReader;
import com.opencsv.bean.CsvToBean;
import com.opencsv.bean.CsvToBeanBuilder;
import java.io.FileReader;
import java.io.IOException;
import java.util.List;
public class CsvToObjectExample {
public static void main(String[] args) {
try (CSVReader reader = new CSVReader(new FileReader("data.csv"))) {
CsvToBean<Person> csvToBean = new CsvToBeanBuilder<Person>(reader)
.withType(Person.class)
.withIgnoreLeadingWhiteSpace(true)
.build();
List<Person> persons = csvToBean.parse();
for (Person person : persons) {
System.out.println(person.getName() + " - " + person.getAge());
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
In the above example, we first created a CSVReader object, which is responsible for reading CSV files.We then use CSVTOBEANBUILEDER to build a CSVTOBEAN object and pass CSVReader and Person.class as parameters.We can also set some other options, such as whether to ignore the first -line blank characters.
Next, we use csvtobean.parse () method to analyze CSV data as a list of Person objects.Finally, we can traverse the list and access the attributes of each Person object.
4. Run code
Save the above example code to CSVTOOBJECTEXAMPLE.java, and name the CSV file to be converted to data.csv.Then we can use the Java compiler and run code:
javac CsvToObjectExample.java
java CsvToObjectExample
If everything goes well, you will see the result of the CSV data converted to the Java object on the console.
By using the OpenCSV library, we can easily convert CSV data into Java objects.In this way, we can handle and operate CSV data more conveniently and use them in a more advanced way.
