Core Java Connectivity with MySQL Part 1

JDBC Connectivity Code with MySQL

STEP 1. Import required packages
STEP 2: Register JDBC driver
STEP 3: Open a connection
STEP 4: Execute a query
STEP 5: Extract data from result set
STEP 6: Clean-up environment

You need to have JDK and Eclipse in your computer. Also driver jar file for MySQL.

This program is to fetch all records from table and display it.

Here i have created
database : test
Table : emp (id, name, city)

//STEP 1. Import required packages
import java.sql.*;

public class FirstExample
{
   // JDBC driver name and database URL
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
   static final String DB_URL = "jdbc:mysql://localhost/test";

   //  Database credentials
   static final String USER = "root";
   static final String PASS = "";
 
   public static void main(String[] args) {
   Connection conn = null;
   Statement stmt = null;
 
   try{
      //STEP 2: Register JDBC driver
      Class.forName("com.mysql.jdbc.Driver");

      //STEP 3: Open a connection
      System.out.println("Connecting to database...");
      conn = DriverManager.getConnection(DB_URL,USER,PASS);

      //STEP 4: Execute a query
      System.out.println("Creating statement...");
      stmt = conn.createStatement();
      String sql;
      sql = "SELECT id, name, city FROM emp";
      ResultSet rs = stmt.executeQuery(sql);

      //STEP 5: Extract data from result set
      while(rs.next())
     {
         //Retrieve by column name
         int id  = rs.getInt("id");
 String name = rs.getString("name");
         String city = rs.getString("city");

         //Display values
         System.out.print("ID: " + id);      
         System.out.print(", Name: " + name);
         System.out.println(", City: " + city);
      }
   
      //STEP 6: Clean-up environment
      rs.close();
      stmt.close();
      conn.close();
   }
   catch(SQLException se){
      //Handle errors for JDBC
      se.printStackTrace();
   }
   catch(Exception e){
      //Handle errors for Class.forName
      e.printStackTrace();
   }
   finally{
      //finally block used to close resources
      try{
         if(stmt!=null)
            stmt.close();
         if(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }//end finally try
   }//end try

   System.out.println("Goodbye!");

}//end main

}//end FirstExample

--------------------------------------------------------------------------------------------------------------------------

import java.sql.*;

class MysqlCon{
public static void main(String args[]){
try{
Class.forName("com.mysql.jdbc.Driver");

Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","");
//here test is the database name, root is the username and password is blank ("")
Statement stmt=con.createStatement();

ResultSet rs=stmt.executeQuery("select * from emp");
//emp is table name having 3 column

while(rs.next())
System.out.println(rs.getInt(1)+"  "+rs.getString(2)+"  "+rs.getString(3));

con.close();

}catch(Exception e){ System.out.println(e);}

}
}