Tools Needed
1. Eclipse IDE
2. MySQL installed.
- Leave mysql default port to 3306 and setup username and password which is required in MyDAO.java files where we indicate the database connections configurations
- Create Database called studentdb and create table called employee.
- In employee table with column id, name and salary insert some data into it.
Lets Start simple Java
- Create Java Project using eclipse IDE. I hope you will understand what is java project, dynamic project and maven projects or ejb project. so simply create java projects.
 |
| JDBC simple java project |
2. Create package in src called com.vastik.jdbc and Create javabean (by definitons should have constructor and setter/getter) called Employee.
package com.vastika.jdbc;
public class Employee {
private int ID;
private String Name;
private int Salary;
public int getID() {
return ID;
}
public void setID(int iD) {
ID = iD;
}
public String getName() {
return Name;
}
public void setName(String name) {
Name = name;
}
public int getSalary() {
return Salary;
}
public void setSalary(int salary) {
Salary = salary;
}
@Override
public String toString() {
return "EmployeeID=" + ID + "\tName=" + Name + "\tSalary=" + Salary;
}
}
3. Create DAO layer that actually deal with database connections and CRUD operations i.e.
create, update, retrieve and delete.
package com.vastika.jdbc;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
public class MyDAO {
private final String SELECT_ALL = "SELECT * FROM employee";
/**
* Create getConnection Method which will allows in establishing the
* connection to database prior to any CRUD operations. i.e. Create,
* Retrieve, Update or Delete.
* */
public Connection getConnetion() {
Connection conn = null;
String url = "jdbc:mysql://localhost:3306/";
String db = "studentdb";
String driver = "com.mysql.jdbc.Driver";
String username = "root";
String password = "test";
try {
/*
* registering with the driver with local mysql host
*/
Class.forName(driver);
conn = DriverManager.getConnection(url + db, username, password);
}
catch (SQLException e1) {
System.out.println("Not Connected check the try block!!!");
}
catch (ClassNotFoundException e2) {
}
return conn;
}
/**
* This getAllEmployee method will first call the getConnection Method to
* get connection to DB, and then fetch the data from database and sets this
* each rows values into each instance of employee object's instance
* variable. And returns List of employee.
* */
List getAllEmployee() {
Connection conn = getConnetion();
List emplList = new ArrayList();
try {
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(SELECT_ALL);
while (rs.next()) {
Employee emp = new Employee();
emp.setID(rs.getInt(1));
emp.setName(rs.getString(2));
emp.setSalary(rs.getInt(3));
emplList.add(emp);
}
}
catch (SQLException e) {
}
return emplList;
}}
4. Make sure your mysql is up and running. Now create Driver class that fetch the data from database and display in the console.
package com.vastika.jdbc;
import java.util.List;
public class Drive {
/**
* @param args
*/
public static void main(String[] args) {
System.out.println("Lets connect to database");
// creating myDAO
MyDAO listEmp = new MyDAO();
List list1 = listEmp.getAllEmployee();
for (Employee emp : list1) {
System.out.println(emp);
}
}
}
Hope you will enjoy this basic of all.
