JDBC Connection: Database connection with MySQL

Step 1:  Create Connection object and getter method if needed. This Interface is inside the java.sql package.

/*
 * This code helpful only for
 * MySQL system. if you want to use with Oracle
 * than change the url and driver registration parameter
 */
public class DBConnection {

    private static Connection conn;

    /*
     * this method will help to get Connection Object
     */
    public static Connection getConn() {
        return conn;
    }

 

Don't miss any step

Step 2: 

load the Driver into your Project. 

Steps

1. download MySQL connector jar file from the Internet.

2. In the case of an eclipse IDE

   1. right-click on project -> property -> Build project

   2. into Library tab, add external jar(add jar file with the name bean).

       

Step 3:

1. In order to access DB, We must have an authentication of the Server and the Database and for that, we need a valid username and password also. 
2. Location of the Database must be needed, Where it is hosted and internal drivers and name and all.

For these, we created 3 variables url, username, password. 

Driver registration is needed to open the communication channel with the database. 

DriverManager(args) Attempts to establish a connection to the given database URL. The DriverManager attempts to select an appropriate driver from the set of registered JDBC drivers.

Formate of the url is jdbc:subprotocol:subname

    /*
     * This method is root of the code
     */
    public static boolean connectToDB(String database) {
        String url;
        String username;
        String password;

        url = "jdbc:mysql://localhost:3306/" + database;
        username = "root";
        password = "";
        try {

            // Registration of Driver
            Class.forName("com.mysql.jdbc.Driver");

            try {
                // Try to open a Connection
                conn = DriverManager.getConnection(url, username, password);

                return true;
            } catch (SQLException e) {
                System.out.println("Problem in username and password or there will no database with name " + database);
                return false;
            }

        } catch (ClassNotFoundException e1) {
            System.out.println("Driver Not Found \nAdd Jar file of Driver in the Project ");
            return false;
        }

    }

Step 4: 

once a connection is established, it is good to close the connection channel in the end.

    /*
     * It is good habit to close the connection this method is for close the
     * connection
     */
    public static void releaseConnection(Connection conn) {
        try {
            conn.close();
        } catch (SQLException e) {
            System.out.println("There is problem in closing connection");
        }
    }

Step 5:

This step may be different in your case.

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.print("Enter Database name: ");
        String databaseName = sc.next();
        boolean status = DBConnection.connectToDB(databaseName);

        if (status) {
            System.out.println("You are connected with database " + databaseName);
            if (DBConnection.getConn() != null) {
                System.out.println("Connection object is found");
            } else {
                System.out.println("Connection is not established yet");
            }
        } else {
            System.out.println("You are not connected with database " + databaseName);
        }

    }

}

The whole code is here
https://github.com/denesvaghani/JDBCConnection-MySQL-

Posted by : Denes Vaghani February 23, 2020 Tags : JDBC

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