使用 Java 泛型创建 CSV 到对象的转换器

import java.io.BufferedReader;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

public class CsvUtils<T> {

    public List<T> read(String fileName, Class<T> clazz) throws IOException, ReflectiveOperationException {
        List<T> objectList = new ArrayList<>();
        Path pathToFile = Paths.get(fileName);

        try (BufferedReader br = Files.newBufferedReader(pathToFile)) {
            String line = br.readLine(); // Skip header line
            while ((line = br.readLine()) != null) {
                String[] attributes = line.split(",");
                T obj = createObject(attributes, clazz);
                objectList.add(obj);
            }
        }

        return objectList;
    }

    private T createObject(String[] attributes, Class<T> clazz) throws ReflectiveOperationException {
        // This is a basic implementation. Consider using a more robust approach, like reflection.
        // Also consider using a CSV parsing library.
        T obj = clazz.getDeclaredConstructor().newInstance();
        // Assuming the class has a constructor with no arguments.
        // And assuming the class has setters for each attribute in the CSV file.
        // The order of the attributes in the CSV file must match the order of the setters in the class.
        // This is a very simple example and should be improved for real-world use.
        if (attributes.length > 0) {
            try {
                clazz.getMethod("setId", int.class).invoke(obj, Integer.parseInt(attributes[0]));
            } catch (NoSuchMethodException e) {
                // Handle exception, e.g., if the class does not have an setId method
            }
        }
        if (attributes.length > 1) {
            try {
                clazz.getMethod("setName", String.class).invoke(obj, attributes[1]);
            } catch (NoSuchMethodException e) {
                // Handle exception, e.g., if the class does not have a setName method
            }
        }
        return obj;
    }
}

import java.io.IOException;
import java.util.List;

public class Main {
    public static void main(String[] args) throws IOException, ReflectiveOperationException {
        CsvUtils<Dog> dogCsvUtils = new CsvUtils<>();
        List<Dog> myDogs = dogCsvUtils.read("MyDogs_V1.csv", Dog.class);

        for (Dog dog : myDogs) {
            System.out.println(dog);
        }

        CsvUtils<Cat> catCsvUtils = new CsvUtils<>();
        List<Cat> myCats = catCsvUtils.read("MyCats_V1.csv", Cat.class);

        for (Cat cat : myCats) {
            System.out.println(cat);
        }
    }
}

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVRecord;

import java.io.IOException;
import java.io.Reader;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

public class CsvUtils<T> {

    public List<T> read(String fileName, Class<T> clazz) throws IOException, ReflectiveOperationException {
        List<T> objectList = new ArrayList<>();
        try (
            Reader reader = Files.newBufferedReader(Paths.get(fileName));
        ) {
            Iterable<CSVRecord> records = CSVFormat.DEFAULT
                    .withHeader("Id","Name") //define header names
                    .withFirstRecordAsHeader()
                    .parse(reader);

            for (CSVRecord record : records) {
                T obj = createObject(record, clazz);
                objectList.add(obj);
            }
        }

        return objectList;
    }

    private T createObject(CSVRecord record, Class<T> clazz) throws ReflectiveOperationException {
        // This is a basic implementation. Consider using a more robust approach, like reflection.
        // Also consider using a CSV parsing library.
        T obj = clazz.getDeclaredConstructor().newInstance();
        // Assuming the class has a constructor with no arguments.
        // And assuming the class has setters for each attribute in the CSV file.
        // The order of the attributes in the CSV file must match the order of the setters in the class.
        // This is a very simple example and should be improved for real-world use.
        try {
            clazz.getMethod("setId", int.class).invoke(obj, Integer.parseInt(record.get("Id")));
        } catch (NoSuchMethodException e) {
            // Handle exception, e.g., if the class does not have an setId method
        }
        try {
            clazz.getMethod("setName", String.class).invoke(obj, record.get("Name"));
        } catch (NoSuchMethodException e) {
            // Handle exception, e.g., if the class does not have a setName method
        }
        return obj;
    }
}