Java のPrintWriter とScanner を使ったCSVファイルの入出力（ReaderとWriter）

CSVPrintWriter.java

package csvwriterreader;

import java.io.PrintWriter;
import java.io.File;
import java.io.FileNotFoundException;

public class CSVPrintWriter {
    PrintWriter pw_;

    // Constructor
    public CSVPrintWriter(String fileName) {
        try {
            this.pw_ = new PrintWriter(fileName);
        } catch (FileNotFoundException fnex) {
            fnex.printStackTrace();
        }
    }

    public CSVPrintWriter(File file) {
        try {
            this.pw_ = new PrintWriter(file);
        } catch (FileNotFoundException fnex) {
            fnex.printStackTrace();
        }
    }

    public void close() {
        this.pw_.close();
    }

    public void print(Object arg) {
        synchronized (this.pw_) {
            this.pw_.print(arg);
            this.pw_.print(",");
        }
    }

    public void println(Object... args) {
        synchronized (this.pw_) {
            for (int i = 0; i < args.length; i++) {
                this.pw_.print(args[i]);
                this.pw_.print(",");
            }
            this.pw_.println();
        }
    }
    
}

CSVScanner.java

package csvwriterreader;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Scanner;

public class CSVScanner {

    Scanner scan_;

    // Constructor
    public CSVScanner(File source) {
        try {
            this.scan_ = new Scanner(source);
        } catch (FileNotFoundException fnex) {
            fnex.printStackTrace();
        }
    }

    public CSVScanner(String source) {
        this.scan_ = new Scanner(source);
    }

    public CSVScanner(InputStream source) {
        this.scan_ = new Scanner(source);
    }

    public ArrayList<String[]> read() {
        ArrayList<String[]> csv_list = new ArrayList<>();
        String[] line_str_arr;
        
        synchronized (this.scan_) {
            while (this.scan_.hasNext()) {
                line_str_arr = this.scan_.nextLine().split(",");
                csv_list.add(line_str_arr);
            }
        }
        return csv_list;
    }

    public void close() {
        this.scan_.close();
    }

}

CSVWriterReader.java

package csvwriterreader;

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;

public class CSVWriterReader {
    /**
     * main
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        String file_name = "test.csv";

        {
            /*write CSV*/
            CSVPrintWriter csvpw = new CSVPrintWriter(file_name);

            csvpw.println(100, "Sato");
            csvpw.println(101, "Suzuki");
            csvpw.println(102, "Tanaka");

            csvpw.close();
        }
        {
            /*read CSV*/
            CSVScanner csvscan = new CSVScanner(new File(file_name));
            
            ArrayList<String[]> csv_data = csvscan.read();
            csv_data.stream().forEach(
                    line->System.out.println(Arrays.toString(line))
            );
            
            csvscan.close();
        }
    }
}