Java Database connectivity perform and using Mysql and java
4.0.0
<groupId>org.example</groupId>
<artifactId>JDBC</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.29</version>
</dependency>
</dependencies>
<properties>
<maven.compiler.source>18</maven.compiler.source>
<maven.compiler.target>18</maven.compiler.target>
</properties>
package db; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException;
public class MyConnection { static Connection connection = null; public static Connection getConnection() { try { Class.forName("com.mysql.cj.jdbc.Driver"); connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/JDBC", "root", "sanskar"); System.out.println("connection ho gya"); }catch (ClassNotFoundException ex) { ex.printStackTrace(); } catch (SQLException ex) { ex.printStackTrace(); } return connection; }
public static void closeConnection(){
}
}
package model;
public class User { private int id; private String name; private String email;
public User(int id, String name, String email) {
this.id = id;
this.name = name;
this.email = email;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", email='" + email + '\'' +
'}';
}
}
package dao;
import db.MyConnection; import model.User;
import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List;
public class UserDAO { public static List getAllUsers() throws SQLException { List users = new ArrayList<>(); Connection conn = MyConnection.getConnection(); PreparedStatement ps = conn.prepareStatement("select * from user"); ResultSet rs = ps.executeQuery(); while (rs.next()) { int id = rs.getInt(1); String name = rs.getString(2); String email = rs.getString(3); User u = new User(id, name, email); users.add(u); } return users; }
public static boolean deleteUser(int id) throws SQLException {
User user = null;
Connection conn = MyConnection.getConnection();
PreparedStatement ps = conn.prepareStatement("select * from user where id = ?");
ps.setInt(1, id);
ResultSet rs = ps.executeQuery();
while (rs.next()) {
id = rs.getInt(1);
String name = rs.getString(2);
String email = rs.getString(3);
user = new User(id, name, email);
}
return user;
}
public static boolean saveUser(User user) throws SQLException {
Connection conn = MyConnection.getConnection();
PreparedStatement ps = conn.prepareStatement("insert into user values(default, ?,?");
ps.setString(1, user.getName());
ps.setString(2, user.getEmail());
int ans = ps.executeUpdate();
return ans == 1;
}
public static boolean updateUser(User user) throws SQLException {
Connection conn = MyConnection.getConnection();
PreparedStatement ps = conn.prepareStatement( "update user set name =?, email =? where id =2");
ps.setString(1, user.getName());
ps.setString(2, user.getEmail());
ps.setInt(3, user.getId());
int ans = ps.executeUpdate();
return ans == 1;
}
public static boolean deleteUser(User id) throws SQLException {
Connection conn = MyConnection.getConnection();
PreparedStatement ps = conn.prepareStatement(" delete from user where id = ?");
ps.setInt(2, id);
int ans = ps.executeUpdate();
return ans == 1;
}
} package controller;
import dao.UserDAO; import model.User;
import java.sql.SQLException; import java.util.List;
public class App { // CRUD - Create , Read , Update , Delete public static void main(String[] args) { try { // List users = UserDAO.getAllUsers(); // for(User u: users) { // System.out.print.ln(u.getId() + "\t" + u.getname()); // } // User u = UserDAO.getUserById(1); // System.out.println(u== null ? "Not found" : u); //Create // User user = new User(0,"saksham","[email protected]"); // boolean ans = UserDAO.saveUser(user); // System.out.println(ans ? "Inserted" : "gadbad ho gyi"); // boolean ans = UserDAO.deleteUser(2); // System.out.println(ans); User user = new User(0,"kunal bhai","[email protected]"); boolean ans = UserDAO.updateUser(user); } catch (SQLException e) { e.printStackTrace(); } } }
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