Java 23种设计模式之原型模式

1. 概念

    用原型实例指定创建对象的种类，并且拷贝这些原型创建新的对象。

2. 创建实体类对象

    1.创建人物对象
    public class Person implements Cloneable{

        private String name;
        private int age;
        private String sex;
        private String workTime;
        private String company;
        private WorkExperience work;

        public Person(String name){
            this.name = name;
            work = new WorkExperience();
        }

        public void setPersonInfo(String sex,int age){
            this.sex = sex;
            this.age = age;
        }

        public void setWorkExperience(String workTime,String company){
            work.setWorkTime(workTime);
            work.setCompany(company);
        }

        @Override
        protected Object clone() throws CloneNotSupportedException {

            Person p = (Person) super.clone();
            return p;
        }

        @Override
        public String toString() {
            return "Person{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    ", sex='" + sex + '\'' +
                    ", workTime='" + work.getWorkTime() + '\'' +
                    ", company='" + work.getCompany() + '\'' +
                    '}';
        }
    }

    2. 创建工作经历对象
    public class WorkExperience {

        private String workTime;
        private String company;

        public String getWorkTime() {
            return workTime;
        }

        public void setWorkTime(String workTime) {
            this.workTime = workTime;
        }

        public String getCompany() {
            return company;
        }

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

3. 浅复制与深复制

    1. 浅复制
     @Override
     protected Object clone() throws CloneNotSupportedException {

            Person p = (Person) super.clone();
            return p;
     }

    2. 深复制
    (1) 工作经历类实现Cloneable
    public class WorkExperience implements Cloneable{

        private String workTime;
        private String company;

        public String getWorkTime() {
            return workTime;
        }

        public void setWorkTime(String workTime) {
            this.workTime = workTime;
        }

        public String getCompany() {
            return company;
        }

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

        @Override
        protected Object clone() throws CloneNotSupportedException{
            WorkExperience work = (WorkExperience)super.clone();
            return work;
        }
    }

    (2) 修改Person 类
    新增一个私有的构造方法 以方便克隆工作经历的数据
    private Person(WorkExperience work) throws CloneNotSupportedException{
        if(work != null){
            this.work = (WorkExperience) work.clone();
        }
    }

    修改clone方法 让工作经历克隆完成
    @Override
    protected Object clone() throws CloneNotSupportedException {

        Person p = new Person(this.work);
        p.name = this.name;
        p.age = this.age;
        p.sex = this.sex;
        return p;

    }

4. 测试

    1. 浅复制
    @org.junit.Test
    public void test1() throws Exception{
        Person p = new Person("郑乐成");
        p.setPersonInfo("男",25);
        p.setWorkExperience("2015-2017","北京盛世冬康科技发展有限公司");


        Person p1 = (Person) p.clone();
        p1.setWorkExperience("2016-2018","北京盛世东康科技发展有限公司");

        System.out.println(p.toString());
        System.out.println(p1.toString());
    }

    结果展示：因为工作经历是同一个引用 所以两条数据都被修改了
    Person{name='郑乐成', age=25, sex='男', workTime='2016-2018', company='北京盛世东康科技发展有限公司'}
    Person{name='郑乐成', age=25, sex='男', workTime='2016-2018', company='北京盛世东康科技发展有限公司'}

    2. 深复制
    @org.junit.Test
    public void test3() throws Exception{
          Person p = new Person("郑乐成");
          p.setPersonInfo("男",25);
          p.setWorkExperience("2014-2017","北京盛世冬康科技发展有限公司");

          Person p1 = (Person) p.clone();
          p1.setPersonInfo("男",26);
          p1.setWorkExperience("2016-2018","北京盛世东康科技发展有限公司");

        System.out.println(p.toString());
        System.out.println(p1.toString());
    }

    结果展示：
    Person{name='郑乐成', age=25, sex='男', workTime='2014-2017', company='北京盛世冬康科技发展有限公司'}
    Person{name='郑乐成', age=26, sex='男', workTime='2016-2018', company='北京盛世东康科技发展有限公司'}

5.小结

    优：
    简化代码，优化设计。