静态工厂方法是否在内部使用new关键字在Java中创建对象？

2024-04-24 17:05:04 329

工厂模式是一种设计模式（创意模式），用于根据我们提供的数据创建多个对象。在其中，我们创建了一个抽象创建过程的对象。

示例

下面给出了工厂模式的示例实现。在这里，我们有一个名为Employee和3类的接口：Student，讲师，NonTeachingStaff，实现了它。我们使用名为的方法创建了一个工厂类(EmployeeFactory)getEmployee()。此方法接受String值，并根据给定的String值返回其中一个类的对象。

import java.util.Scanner;
interface Person{
   void dsplay();
}
class Student implements Person{
   public void dsplay() {
      System.out.println("This is display method of the Student class");
   }
}
class Lecturer implements Person{
   public void dsplay() {
      System.out.println("This is display method of the Lecturer class");
   }
}
class NonTeachingStaff implements Person{
   public void dsplay() {
      System.out.println("This is display method of the NonTeachingStaff class");
   }
}
class PersonFactory{
   public Person getPerson(String empType) {
      if(empType == null){
         return null;
      }
      if(empType.equalsIgnoreCase("student")){
         return new Student();
      } else if(empType.equalsIgnoreCase("lecturer")){
         return new Lecturer();
      } else if(empType.equalsIgnoreCase("non teaching staff")){
         return new NonTeachingStaff();
      }
      return null;
   }
}
public class FactoryPattern {
   public static void main(String args[]) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter the type of the object you want: (student, lecturer, non teaching staff)");
      String type = sc.next();
      PersonFactory obj = new PersonFactory();
      Person emp = obj.getPerson(type);
      emp.dsplay();
   }
}

输出结果

Enter the type of the object you want: (student, lecturer, non teaching staff)
lecturer
This is display method of the Lecturer class

静态工厂方法

虽然据说有五种方法可以在Java中创建对象-

使用new关键字。

使用工厂方法。

使用克隆。

使用Class.forName()。

使用对象反序列化。

用Java创建对象的唯一方法是使用new关键字，其他所有方法都是对该对象的抽象。所有这些方法在内部都完整地使用new关键字。

示例

import java.util.Scanner;
interface Employee{
   void dsplay();
}
class Student implements Employee{
   public void dsplay() {
      System.out.println("This is display method of the Student class");
   }
}
class Lecturer implements Employee{
   public void dsplay() {
      System.out.println("This is display method of the Lecturer class");
   }
}
class NonTeachingStaff implements Employee{
   public void dsplay() {
      System.out.println("This is display method of the NonTeachingStaff class");
   }
}
class EmployeeFactory{
   public static Employee getEmployee(String empType) {
      if(empType == null){
         return null;
      }
      if(empType.equalsIgnoreCase("student")){
         return new Student();
      } else if(empType.equalsIgnoreCase("lecturer")){
         return new Lecturer();
      } else if(empType.equalsIgnoreCase("non teaching staff")){
         return new NonTeachingStaff();
      }
      return null;
   }
}
public class FactoryPattern {
   public static void main(String args[]) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter the type of the object you want: (student, lecturer, non teaching staff)");
      String type = sc.next();
      EmployeeFactory obj = new EmployeeFactory();
      Employee emp = EmployeeFactory.getEmployee(type);
      emp.dsplay();
   }
}

输出结果

Enter the type of the object you want: (student, lecturer, non teaching staff)
lecturer
This is display method of the Lecturer class

静态工厂方法是否在内部使用new关键字在Java中创建对象？

示例

静态工厂方法

示例

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