如何基于列java的值将csv文件拆分为多个文件？

Question

我需要找到一种方法，根据输入的csv文件中特定列的值将csv文件拆分为多个csv文件。我还需要新生成的csv文件的名称作为该列的值。

For example:

input CSV file = 

Col1,Col2,Col3
1,2,Cat
1,3,Cat
2,4,Dog
2,5,Dog

I want to split by Col3 so I get the following table and file name:

---------------- File name = Cat.csv
Col1,Col2,Col3
1,2,Cat
1,3,Cat



---------------- File name = Dog.csv
Col1,Col2,Col3
2,4,Dog
2,5,Dog

有什么办法吗？

感谢您的帮助。

到目前为止，我只能读取文件并保存在对象中。

    package com.jcg;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class CsvFileReader {

    private static final String COMMA_DELIMITER = ",";

    private static final int ORDER_ID_IDX = 0;
    private static final int ORDER_DATE_IDX = 1;
    private static final int ORDER_COUNTRY_IDX = 2;
    private static final int ORDER_VALUE = 3;

    public static void readCsvFile(String fileName) {

        BufferedReader fileReader = null;

        try {

            List<Order> orders = new ArrayList<Order>();

            String line = "";

            fileReader = new BufferedReader(new FileReader(fileName));

            fileReader.readLine();

            while ((line = fileReader.readLine()) != null) {
                String[] tokens = line.split(COMMA_DELIMITER);
                if (tokens.length > 0) {
                    Order order = new Order(Long.parseLong(tokens[ORDER_ID_IDX]), tokens[ORDER_DATE_IDX],
                            tokens[ORDER_COUNTRY_IDX], tokens[ORDER_VALUE]);
                    orders.add(order);
                }
            }

            for (Order order : orders) {
                System.out.println(order.toString());

            }
        } catch (Exception e) {
            System.out.println("Error in CsvFileReader !!!");
            e.printStackTrace();
        } finally {
            try {
                fileReader.close();
            } catch (IOException e) {
                System.out.println("Error while closing fileReader !!!");
                e.printStackTrace();
            }
        }

    }

}

Order.java

    package com.jcg;

public class Order {

    private long id;
    private String dates;
    private String country;
    private String values;

    public Order(long id, String dates, String country, String values) {
        super();
        this.id = id;
        this.dates = dates;
        this.country = country;
        this.values = values;
    }

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getDates() {
        return dates;
    }

    public void setDates(String dates) {
        this.dates = dates;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    public String getValues() {
        return values;
    }

    public void setValues(String values) {
        this.values = values;
    }

    @Override
    public String toString() {
        return "Order [id=" + id + ", dates=" + dates + ", country=" + country + ", values=" + values + "]";
    }
}