《大话设计模式》Java代码示例（六）之原型模式

原型模式（Prototype）：用原型实例指定创建对象的种类，并且通过拷贝这些原型创建新的对象。

 

一、浅拷贝：被复制对象的所有变量都含有与原来对象相同的值，而所有的对其他对象的引用都仍然指向原来的对象。

package prototype.bitwisecopy;

/**
 * 原型模式(Prototype):浅拷贝
 * 工作经历类
 */
public class WorkExperience {

    private String workDate;

    private String company;

    public String getWorkDate() {
        return workDate;
    }

    public void setWorkDate(String workDate) {
        this.workDate = workDate;
    }

    public String getCompany() {
        return company;
    }

    public void setCompany(String company) {
        this.company = company;
    }

}

package prototype.bitwisecopy;

/**
 * 原型模式(Prototype):浅拷贝
 * 简历类
 */
public class Resume implements Cloneable {

    private String name;

    private String sex;

    private String age;

    private WorkExperience workExperience;

    public Resume(String name) {
        this.name = name;
        workExperience = new WorkExperience();
    }

    // 设置个人信息
    public void setPersonalInfo(String sex, String age) {
        this.sex = sex;
        this.age = age;
    }

    // 设置工作经历
    public void setWorkExperience(String workDate, String company) {
        workExperience.setWorkDate(workDate);
        workExperience.setCompany(company);
    }

    // 显示
    public void display() {
        System.out.println("姓名：" + name + "，性别：" + sex + "，年龄：" + age);
        System.out.println("工作经历：" + workExperience.getWorkDate() + "，" + workExperience.getCompany());
    }

    @Override
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }

}

package prototype.bitwisecopy;

/**
 * 原型模式(Prototype):浅拷贝
 * 客户端main方法
 */
public class Client {

    public static void main(String[] args) throws CloneNotSupportedException {
        Resume r0 = new Resume("大鸟");
        r0.setPersonalInfo("男", "29");
        r0.setWorkExperience("1998-2000", "xx公司");

        Resume r1 = (Resume) r0.clone();
        r1.setWorkExperience("1998-2006", "yy企业");

        Resume r2 = (Resume) r0.clone();
        r2.setPersonalInfo("女", "18");
        r2.setWorkExperience("1998-2003", "zz企业");

        // 浅拷贝中工作经历的显示结果都是最后一次设置的值
        r0.display();
        r1.display();
        r2.display();

    }

}

输出结果：
姓名：大鸟，性别：男，年龄：29
工作经历：1998-2003，zz企业
姓名：大鸟，性别：男，年龄：29
工作经历：1998-2003，zz企业
姓名：大鸟，性别：女，年龄：18
工作经历：1998-2003，zz企业

二、深拷贝：把引用对象的变量指向复制过的新对象，而不是原有的被引用的对象。

package prototype.memberwisecopy;

/**
 * 原型模式(Prototype):深拷贝
 * 工作经历类
 */
public class WorkExperience implements Cloneable {

    private String workDate;

    private String company;

    public String getWorkDate() {
        return workDate;
    }

    public void setWorkDate(String workDate) {
        this.workDate = workDate;
    }

    public String getCompany() {
        return company;
    }

    public void setCompany(String company) {
        this.company = company;
    }

    @Override
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }

}

package prototype.memberwisecopy;

/**
 * 原型模式(Prototype):深拷贝
 * 简历类
 */
public class Resume implements Cloneable {

    private String name;

    private String sex;

    private String age;

    private WorkExperience workExperience;

    public Resume(String name) {
        this.name = name;
        this.workExperience = new WorkExperience();
    }

    public Resume(WorkExperience workExperience) throws CloneNotSupportedException {
        this.workExperience = (WorkExperience) workExperience.clone();
    }

    // 设置个人信息
    public void setPersonalInfo(String sex, String age) {
        this.sex = sex;
        this.age = age;
    }

    // 设置工作经历
    public void setWorkExperience(String workDate, String company) {
        workExperience.setWorkDate(workDate);
        workExperience.setCompany(company);
    }

    // 显示
    public void display() {
        System.out.println("姓名：" + name + "，性别：" + sex + "，年龄：" + age);
        System.out.println("工作经历：" + workExperience.getWorkDate() + "，" + workExperience.getCompany());
    }

    @Override
    public Object clone() throws CloneNotSupportedException {
        Resume resume = new Resume(this.workExperience);
        resume.name = this.name;
        resume.sex = this.sex;
        resume.age = this.age;
        return resume;
    }

}

package prototype.memberwisecopy;

/**
 * 原型模式(Prototype):深拷贝
 * 客户端main方法
 */
public class Client {

    public static void main(String[] args) throws CloneNotSupportedException {
        Resume r0 = new Resume("大鸟");
        r0.setPersonalInfo("男", "29");
        r0.setWorkExperience("1998-2000", "xx公司");

        Resume r1 = (Resume) r0.clone();
        r1.setWorkExperience("1998-2006", "yy企业");

        Resume r2 = (Resume) r0.clone();
        r2.setPersonalInfo("女", "18");
        r2.setWorkExperience("1998-2003", "zz企业");

        // 深拷贝中工作经历的显示结果各不相同
        r0.display();
        r1.display();
        r2.display();

    }

}

输出结果：
姓名：大鸟，性别：男，年龄：29
工作经历：1998-2000，xx公司
姓名：大鸟，性别：男，年龄：29
工作经历：1998-2006，yy企业
姓名：大鸟，性别：女，年龄：18
工作经历：1998-2003，zz企业