Adding column name as a value in to a query in jdbc connection (javalin) | Together Java | Page 1

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<@&987246584574140416> please have a look, thanks.

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This is the code

import io.javalin.Javalin;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class JDBCTest {

    public static void main(String[] args) {
        Javalin app = Javalin.create().start(7000);

        // Create a route to handle queries
        app.get("/query/:columnName", ctx -> {
            String columnName = ctx.pathParam("columnName");
            
            try {
                Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");
                String query = "SELECT " + columnName + " FROM mytable";
                PreparedStatement stmt = conn.prepareStatement(query);
                ResultSet rs = stmt.executeQuery();
                
                while(rs.next()) {
                    System.out.println(rs.getString(columnName));
                }
                
                conn.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
    }
}

In this code snippet, we are using Javalin to create a simple web server that listens for GET requests on the "/query/:columnName" endpoint. The endpoint expects a path parameter called "columnName" which will be used in the SQL query to retrieve data from a MySQL database.

We establish a JDBC connection to the database, construct a SQL query dynamically by including the column name provided in the path parameter, and execute the query using a prepared statement. We then loop through the result set to print out the values of the specified column.

This code demonstrates how you can add a column name as a value in a query when working with JDBC connections in Java, specifically within the context of a Javalin web server.

#Adding column name as a value in to a query in jdbc connection (javalin)