java深copy (伪深copy)【原】

Z时代
2024-01-10
分类：综合

java

Teacher.java

package test.clone;
/**
 * 老师
 * 深copy需要实现Cloneable接口
 * @author King
 *
 */
public class Teacher implements Cloneable {
    private String name;
    private int age;
    public 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;
    }
    @Override
    public String toString() {
        return "Teacher [name=" + name + ", age=" + age + "]";
    }
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
}

Student.java

package test.clone;
/**
 * 学生
 * 浅copy需要实现Cloneable接口
 * @author King
 *
 */
public class Student implements Cloneable {
    private String name;
    private int age;
    private Teacher teacher;
    public 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 Teacher getTeacher() {
        return teacher;
    }
    public void setTeacher(Teacher teacher) {
        this.teacher = teacher;
    }
    @Override
    public String toString() {
        return "Student [name=" + name + ", age=" + age + ", Teacher=" + teacher + "]";
    }
    //浅copy
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
    /**
     * 浅copy (同clone()方法)
     * 浅copy只对基本类型和String类型做全新复制,
     * 属性对象引用是不会全新复制的,最终新copy出来的属性对象引用的还是同一个堆内存区域,比如teacher属性
     * @return
     * @throws CloneNotSupportedException
     * ......
     * @time 2018年1月26日 下午8:07:11
     * @author King
     */
    public Object shallowClone() throws CloneNotSupportedException {
        return super.clone();
    }
    /**
     * 伪深copy
     * 这种伪深copy模式,其实还是使用了浅copy技术,只是把属性对象再次赋了新的浅copy.
     * 当对象比较简单时可以用这种模式,因为它比序列化深copy要来得快,还是定制化copy哪些属性
     * @return
     * @throws CloneNotSupportedException
     * ......
     * @time 2018年1月26日 下午8:09:39
     * @author King
     */
    public Object deepClone() throws CloneNotSupportedException {
        Student stu = (Student) super.clone();
        Teacher t2 =  (Teacher) teacher.clone();
        stu.setTeacher(t2);
        return stu;
    }
}

FakeDeepCopy.java

伪深copy调用样例

package test.clone;
/**
 * fakeDeepCopy,其实是一种伪深copy,对象对比简单时可以使用这种技术
 * 
 * @author King
 *
 */
public class FakeDeepCopy {
    public static void main(String[] args) {
        Teacher techarAAA = new Teacher();
        techarAAA.setName("Teacher AAA");
        techarAAA.setAge(30);
        Student studentAAA = new Student();
        studentAAA.setName(new String("Student AAA"));
        studentAAA.setAge(15);
        studentAAA.setTeacher(techarAAA);
        System.out.println("学生复制前studentAAA:" + studentAAA);
        try {
            Student studentCopy = (Student) studentAAA.clone();
            Teacher teacherCopy = studentCopy.getTeacher();
            studentCopy.setName(new String("Student BBB"));
            studentCopy.setAge(20);
            teacherCopy.setName("Teacher BBB");
            teacherCopy.setAge(45);
            studentCopy.setTeacher(teacherCopy);
            System.out.println("学生复制后studentAAA:" + studentAAA);
            System.out.println("学生复制后studentCopy:" + studentCopy);
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
    }
}