静态工厂方法是否在内部使用new关键字在Java中创建对象？
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