database - How to pass the column name as dynamically in Postgres query in java

Question

I want to pass the postgresql column names as dynamically on the execute query in java.I have created table and table name is product which has 4 columns(year, product,no,age).I have established the db connection and trying to pass the columns dynamically. I have created one pogo class which is having getter and setter of columns names.How can I pass the columns name dynamically on execute query.

dbcon.java

import java.sql.*;
import java.sql.Connection;
public class dbcon  {

    public static void main(String[] args) {
        Connection conn =null;
        Statement stmt = null;
        DatabaseStatus databaseStatus = new DatabaseStatus();
        try
        {
            Class.forName("******");
            conn = DriverManager.getConnection("************", "*******", "*******");
            stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("Select "+databaseStatus.getYear()+","+databaseStatus.getProduct()+","+databaseStatus.getNo()+","+databaseStatus.getAge()+" FROM "Products";");
            
            while(rs.next()){
                System.out.println(rs.getString("Year").trim());
                System.out.println(rs.getString("Product").trim());
                System.out.println(rs.getString("No.").trim());
                System.out.println(rs.getString("Age").trim());
                
            }
        } 
        catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                stmt.close(); 
                conn.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }   
}

datastatus.java

public class DatabaseStatus {
    private String No;
    private String Year;
    private String Product;
    private String Age;
    
    public String getNo() {
        return No;
    }
    public void setNo(String no) {
        No = no;
    }
    public String getYear() {
        return Year;
    }
    public void setYear(String year) {
        Year = year;
    }
    public String getProduct() {
        return Product;
    }
    public void setProduct(String product) {
        Product = product;
    }
    public String getAge() {
        return Age;
    }
    public void setAge(String age) {
        Age = age;
    }
}

table 

SELECT "Year", "Product", "No.", "Age"
    FROM "Products";

question from:https://stackoverflow.com/questions/66046475/how-to-pass-the-column-name-as-dynamically-in-postgres-query-in-java

Answer 1

If you really want use the setters.

databaseStatus.setNo("No.");
databaseStatus.setYear( "Year");
databaseStatus.setProduct("Product");
databaseStatus.setAge("Age");

else remove the setters and

public class DatabaseStatus {
    private String No = "No.";
    private String Year =  "Year";
    private String Product = "Product";
    private String Age = "Age";

    public String getNo() {…
}