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Java创建型模式---原型模式

news 2025/7/8 15:31:43

原型模式基础概念

原型模式是一种创建型设计模式，其核心思想是通过复制（克隆）现有对象来创建新对象，而无需依赖显式的类实例化过程。这种模式适用于创建对象成本较高（如初始化时间长、资源消耗大）或需要避免复杂的对象创建逻辑的场景。

原型模式的核心组件

原型接口 (Prototype) - 定义克隆方法的接口
具体原型类 (ConcretePrototype) - 实现原型接口，提供克隆方法的具体实现
客户端 (Client) - 通过调用原型对象的克隆方法来创建新对象

浅克隆与深克隆

在 Java 中，克隆分为两种类型：

浅克隆 (Shallow Clone) - 复制对象时，仅复制对象本身及其基本数据类型字段，而引用类型字段仍指向原对象的引用

深克隆 (Deep Clone) - 复制对象时，不仅复制对象本身，还递归复制其引用类型字段，确保新对象和原对象完全独立

原型模式的实现

下面通过示例代码展示原型模式的实现：

import java.util.ArrayList;
import java.util.List;// 原型接口
interface Prototype {Prototype clone();
}// 具体原型类 - 浅克隆示例
class Employee implements Prototype, Cloneable {private String name;private int age;private List<String> skills; // 引用类型字段public Employee(String name, int age, List<String> skills) {this.name = name;this.age = age;this.skills = skills;}// Getters and setterspublic String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public List<String> getSkills() {return skills;}public void setSkills(List<String> skills) {this.skills = skills;}// 浅克隆实现@Overridepublic Employee clone() {try {// 调用Object类的clone()方法进行浅克隆Employee cloned = (Employee) super.clone();return cloned;} catch (CloneNotSupportedException e) {e.printStackTrace();return null;}}@Overridepublic String toString() {return "Employee{" +"name='" + name + '\'' +", age=" + age +", skills=" + skills +'}';}
}// 具体原型类 - 深克隆示例
class Department implements Prototype, Cloneable {private String deptName;private Employee manager; // 引用类型字段public Department(String deptName, Employee manager) {this.deptName = deptName;this.manager = manager;}// Getters and setterspublic String getDeptName() {return deptName;}public void setDeptName(String deptName) {this.deptName = deptName;}public Employee getManager() {return manager;}public void setManager(Employee manager) {this.manager = manager;}// 深克隆实现@Overridepublic Department clone() {try {// 调用Object类的clone()方法进行浅克隆Department cloned = (Department) super.clone();// 手动深克隆引用类型字段if (this.manager != null) {// 递归克隆manager对象Employee clonedManager = this.manager.clone();// 为避免无限递归，需要在Employee类中实现深克隆// 这里假设Employee类已经正确实现了深克隆cloned.manager = clonedManager;}return cloned;} catch (CloneNotSupportedException e) {e.printStackTrace();return null;}}@Overridepublic String toString() {return "Department{" +"deptName='" + deptName + '\'' +", manager=" + manager +'}';}
}// 原型管理器 - 集中管理原型对象
class PrototypeManager {private static final java.util.Map<String, Prototype> prototypes = new java.util.HashMap<>();static {// 初始化一些原型对象List<String> skills = new ArrayList<>();skills.add("Java");skills.add("Spring");Employee employeePrototype = new Employee("Prototype Employee", 30, skills);prototypes.put("employee", employeePrototype);Department deptPrototype = new Department("IT Department", employeePrototype);prototypes.put("department", deptPrototype);}// 获取原型对象的克隆public static Prototype getClone(String key) {Prototype prototype = prototypes.get(key);if (prototype != null) {return prototype.clone();}return null;}// 注册新的原型对象public static void registerPrototype(String key, Prototype prototype) {prototypes.put(key, prototype);}
}// 客户端代码
public class PrototypePatternClient {public static void main(String[] args) {// 使用原型管理器获取克隆对象Employee clonedEmployee = (Employee) PrototypeManager.getClone("employee");Department clonedDepartment = (Department) PrototypeManager.getClone("department");System.out.println("Original Employee: " + PrototypeManager.getClone("employee"));System.out.println("Cloned Employee: " + clonedEmployee);System.out.println("\nOriginal Department: " + PrototypeManager.getClone("department"));System.out.println("Cloned Department: " + clonedDepartment);// 验证浅克隆和深克隆的效果// 修改克隆对象的基本类型字段clonedEmployee.setAge(35);// 修改克隆对象的引用类型字段List<String> clonedSkills = clonedEmployee.getSkills();clonedSkills.add("Hibernate");System.out.println("\nAfter modification:");System.out.println("Original Employee: " + PrototypeManager.getClone("employee"));System.out.println("Cloned Employee: " + clonedEmployee);// 验证深克隆Employee clonedManager = clonedDepartment.getManager();clonedManager.setName("New Manager");System.out.println("\nAfter manager modification:");System.out.println("Original Department Manager: " + ((Department) PrototypeManager.getClone("department")).getManager().getName());System.out.println("Cloned Department Manager: " + clonedDepartment.getManager().getName());}
}