Implementación del Patrón Repositorio en Java

Declarar la URL, el usuario y la contraseña como constantes utilizando la palabra clave final es una buena práctica, ya que estos valores no cambiarán durante la ejecución del programa:

private static final String URL = "jdbc:mysql://localhost:3306/project";
private static final String USER = "user";
private static final String PASSWORD = "password";

se que talvez aca no se vea eso, pero java no usa .env como otros lenguajes? es que eso de subir la info de la conección a la db como que no lo veo bien.

El patrón Singleton es un diseño que asegura que una clase tenga una única instancia y proporciona un punto de acceso global a esa instancia. En el contexto de tu clase, se utiliza para manejar la conexión a la base de datos, garantizando que no se creen múltiples conexiones innecesarias. Esto optimiza el uso de recursos y evita problemas de concurrencia. La instancia se accede a través de un método estático, generalmente llamado `getInstance()`, que crea la instancia solo si no existe una.

package CAPAS.UTILITARIO; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; public class CONECTARBD { private static String url="jdbc:mysql://localhost:3306/cuarto"; private static String user="root"; private static String pass="JACZ"; private static Connection myConn; public static Connection getInstance() throws SQLException { if (myConn == null) { myConn = DriverManager.getConnection(url, user, pass); } return myConn; } }

Estás cerrando la conexión creada en el Singleton... piénsalo

Codigo

public class DatabaseConnection{
    private static String url = "jdbc:mysql://localhost:3306/basicos_jdbc";
    private static String user = "root";
    private static String password = "9PM8tv$h#$*e";

    private static Connection instance;

    public static Connection getInstance() throws SQLException {
        if(instance == null) instance = DriverManager.getConnection(url, user, password);
        System.out.println("CONEXION EXITOSA");
        return instance;
    }
}




public class Main {
    public static void main(String[] args){
        try (Connection myConn = DatabaseConnection.getInstance()){
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("Conexión errada");
        }
    }
}

**Yo use db de ejemplo, asi que tuve que adaptar, tambien cree un enum para genero.** ```java package org.example.tmendoza.model; import java.util.Date; public class Employee { private Integer emp_no; private Date birth_date; private String first_name; private String last_name; private Gender gender; private Date hire_date; private String email; public Employee(Integer emp_no, Date birth_date, String first_name, String last_name, Gender gender, Date hire_date, String email) { this.emp_no = emp_no; this.birth_date = birth_date; this.first_name = first_name; this.last_name = last_name; this.gender = gender; this.hire_date = hire_date; this.email = email; } public Integer getEmp_no() { return emp_no; } public void setEmp_no(Integer emp_no) { this.emp_no = emp_no; } public Date getBirth_date() { return birth_date; } public void setBirth_date(Date birth_date) { this.birth_date = birth_date; } public String getFirst_name() { return first_name; } public void setFirst_name(String first_name) { this.first_name = first_name; } public String getLast_name() { return last_name; } public void setLast_name(String last_name) { this.last_name = last_name; } public Gender getGender() { return gender; } public void setGender(Gender gender) { this.gender = gender; } public Date getHire_date() { return hire_date; } public void setHire_date(Date hire_date) { this.hire_date = hire_date; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } @Override public String toString() { return "Employee{" + "emp_no=" + emp_no + ", birth_date=" + birth_date + ", first_name='" + first_name + '\'' + ", last_name='" + last_name + '\'' + ", gender=" + gender + ", hire_date=" + hire_date + ", email='" + email + '\'' + '}'; } } ```package org.example.tmendoza.model; import java.util.Date; public class Employee { private Integer emp\_no; private Date birth\_date; private String first\_name; private String last\_name; private Gender gender; private Date hire\_date; private String email; public Employee(Integer emp\_no, Date birth\_date, String first\_name, String last\_name, Gender gender, Date hire\_date, String email) { this.emp\_no = emp\_no; this.birth\_date = birth\_date; this.first\_name = first\_name; this.last\_name = last\_name; this.gender = gender; this.hire\_date = hire\_date; this.email = email; } public Integer getEmp\_no() { return emp\_no; } public void setEmp\_no(Integer emp\_no) { this.emp\_no = emp\_no; } public Date getBirth\_date() { return birth\_date; } public void setBirth\_date(Date birth\_date) { this.birth\_date = birth\_date; } public String getFirst\_name() { return first\_name; } public void setFirst\_name(String first\_name) { this.first\_name = first\_name; } public String getLast\_name() { return last\_name; } public void setLast\_name(String last\_name) { this.last\_name = last\_name; } public Gender getGender() { return gender; } public void setGender(Gender gender) { this.gender = gender; } public Date getHire\_date() { return hire\_date; } public void setHire\_date(Date hire\_date) { this.hire\_date = hire\_date; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } @Override public String toString() { return "Employee{" + "emp\_no=" + emp\_no + ", birth\_date=" + birth\_date + ", first\_name='" + first\_name + '\\'' + ", last\_name='" + last\_name + '\\'' + ", gender=" + gender + ", hire\_date=" + hire\_date + ", email='" + email + '\\'' + '}'; } }