Java之不通过构造函数创建一个对象问题

package pxx;
 
public class Demo2 {
    public static void main(String[] args) throws CloneNotSupportedException {
        //利用构造创建了一个对象，这里会调用一下无参构造
        TestDemo2 testDemo1 = new TestDemo2();
        //利用clone()方法创建了一个对象，没有构造方法调用
        TestDemo2 testDemo2 = (TestDemo2) testDemo1.clone();
        testDemo2.setName("周杰伦");
        System.out.println(testDemo1.getName());
        System.out.println(testDemo2.getName());
    }
}
 
class TestDemo2 implements  Cloneable{
    private String  name = "孙悟空";
 
    public TestDemo2() {
        System.out.println("该类无参构造方法");
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    //在这个方法里面克隆对象
    @Override
    protected Object clone() throws CloneNotSupportedException {
       Object o = null;
       //调用父类的clone方法，返回这个对象
        o = (TestDemo2)super.clone();
        return o;
    }
}

package domain;
 
public class Person {
    private String name;
    private int age;
 
    public String a;
    protected String b;
    String c;
    private String d;
 
 
    public Person() {
        System.out.println("无参构造调用了");
    }
 
    public Person(String name, int age) {
 
        this.name = name;
        this.age = 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 "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", a='" + a + '\'' +
                ", b='" + b + '\'' +
                ", c='" + c + '\'' +
                ", d='" + d + '\'' +
                '}';
    }
 
    public  void eat(){
        System.out.println("eat...");
    }
 
    public void eat(String food){
        System.out.println("eat..."+food);
    }
}

package reflect;
 
import domain.Person;
 
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
 
public class Reflect4 {
    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
 
        //获得class类对象，类文件
        Class  person = Class.forName("domain.Person");
        //利用反射构造一个对象,这里是拿到无参构造函数
        Constructor cons1 = person.getConstructor();
        Object obj = cons1.newInstance();//其实这里还是调用了构造方法
        Person p1 = (Person)obj;
        p1.setName("张三");
        System.out.println(p1.getName());
    }
 
}

package domain;
 
import java.io.Serializable;
import java.util.Date;
 
public class Person implements Serializable {
    String name;
    int age;
    String gender;
    //添加了一个短暂属性，表明这个字段不可别序列化
    transient Date birthday;
 
    public Date getBirthday() {
        return birthday;
    }
 
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
 
    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 String getGender() {
        return gender;
    }
 
    public void setGender(String gender) {
        this.gender = gender;
    }
}

package test;
 
import domain.Person;
 
import java.io.*;
 
public class DeserializeTest1 {
    public static void main(String[] args)  {
        //将文件进行反序列化
        Person p = null;
        //建立一个反序列化对象
        //这里是.ser序列化的文件
        FileInputStream fis = null;
        ObjectInputStream objectInputStream = null;
        try {
            fis = new FileInputStream("D:/w.ser");
            objectInputStream = new ObjectInputStream(fis);
            p = (Person) objectInputStream.readObject();
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            try {
                objectInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
 
        //上面就会反序列化之前我们在文件中存放的对象
        //然后访问一下之前创建的对象
        System.out.println("Name: " + p.getName());
        System.out.println("age: " + p.getAge());
        System.out.println("gender: " + p.getGender());
        System.out.println("birthday: " + p.getBirthday());
    }
}