the constructor csvreader(reader char) is deprecated error

Question

I want to upload file CSV to MySQL with servlet and I have code like this and I got an error from my code.

package ServToDb;

import java.io.*;
import java.sql.*;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;

import com.opencsv.CSVReader;


import Connection.Database;

@WebServlet("/ImportCSVtoDB")
public class ImportCSVtoDB extends HttpServlet {
    private static final long serialVersionUID = 1L;       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ImportCSVtoDB() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doPost(request, response);
    }


    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        String target_file ;  // fileThatYouWantToFilter
        File folderToScan = new File("C:/Users/DELL/Music/"); //  this is the path we are scanning        
        File[] listOfFiles = folderToScan.listFiles();// this is the list of files returned in this folder       
        for (int j = 0; j < listOfFiles.length; j++) { // for each file in the folder
            if (listOfFiles[j].isFile()) {
                target_file = listOfFiles[j].getName();
                if (target_file.equals("blog.csv")) { // look for the file. You can also check if it ends with csv etc.              
            try 
            {
                Database db = new Database(); 
                String loadQuery = "LOAD DATA LOCAL INFILE 'C:/Users/DELL/Music/csvtest.csv' INTO TABLE" 
                        + "importcsv FIELDS TERMINATED BY ','LINES TERMINATED BY '\n' (fname, sex) "; //remember to change the path here as well
                Statement stmt = db.dbConn().createStatement();
                stmt.execute(loadQuery);                            
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }                   
            try (CSVReader reader = new CSVReader(new FileReader("C:/Users/DELL/Music/" + target_file), ',');)
            {
                Database db = new Database();
                String insertQuery = "Insert into importcsv (fname, sex) values (?,?)";//write your insertion query
                PreparedStatement pstmt = db.dbConn().prepareStatement(insertQuery);
                String[] rowData = null;// create empty array which will hold values from csv
                while((rowData = reader.readNext()) != null)
                {
                    int i = 0;
                    for (String data : rowData)
                        {
                        i++; 
                            if (i<3) {
                                pstmt.setString(i, data);
                                    if (i == 2) {
                                        pstmt.addBatch();// add batch
                                    }
                                    if (i % 30 == 0)// insert when the batch size is 10
                                        {
                                        pstmt.executeBatch(); // execute queries
                                        }
                            }
                        }
                }

            }
            catch (Exception e) {
                e.printStackTrace();}
                }
            }
        }
        out.println("success");
    }
}

but i get error like this.

The constructor CSVReader(Reader, char) is deprecated

from line 60

try (CSVReader reader = new CSVReader(new FileReader("C:/Users/DELL/Music/" + target_file), ',');)

How can I make this code running please help me, Thank you in advance for any help. I'm not looking to have this done for me, I'm just stuck and need help finding my way.

Answer 1

The real answer here:

• you search for the term deprecated
• you then find out: deprecated means that some method is marked so that you should not use it any more (see here)
• note the should: you can still use it, but some future version of the library will maybe remove that ctor/method, and then your code will not compile any more (meaning: the above is a warning, and theoretically you can ignore it)
• but ignoring is the wrong approach.

Instead: you turn to the javadoc for the class you are using (probably here), to there find:

Deprecated. Please use CSVReaderBuilder instead.

And that builder class is documented here, including an usage example.

Beyond that: if you really get an error (like your IDE telling you it is an error), then that is because your configured your IDE setup in a way that this warning is flagged as error (so this is again something that you could influence yourself easily).

Finally: the really real answer here is to not put down code you do not understand. It seems you got code from somewhere, and you started using it, without doing any research what exactly that code is doing. That is an inefficient approach. You want to understand each and character in your source code. If you don't understand something, then you research that, until you understand it. That is how you learn programming.

Answer 2

Here is the exact solution for deprecated code:

CSVParser csvParser = new CSVParserBuilder().withSeparator(',').build();

CSVReader reader = new CSVReaderBuilder(new FileReader("C:/Users/DELL/Music/" + 
target_file)).withCSVParser(csvParser).build();

Answer 3

You could just use a Scanner unless you're specifically trying to use that CSV reader package?

Scanner scanner = new Scanner("fileName.csv"); //open the file
while(scanner.hasNextLine()) { //Iterate through the file
    String line = scanner.nextLine(); //grab the next line
    String[] lineParts = line.split(","); //split based on commas and do something with the data
}
scanner.close(); //close the file