java创建对象的方法

public class Student {
    String name;
    int age;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }
}

1. new 一个对象

 Student student = new Student("张三",18);

2. 克隆一个对象
   需要副本类先实现Clonable接口，并实现其clone()方法

public class Student implements Cloneable{
    String name;
    int age;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }
    @Override
    protected Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
}

 Student student = new Student("张三",18);
        try {
            Student student1 = (Student) student.clone();
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }

快速创建一个和原对象值相同，但是对象引用地址不同的对象。

3. 反射：派发一个类

 Student student2 = Student.class.newInstance();

4. 反射：动态加载

Student student3 = (Student) Class.forName("类的全路径").newInstance();

5. 反射：构造一个对象

  Student student4 = Student.class.getConstructor().newInstance();

6. 反序列话一个对象
   副本类需要先实现序列化接口

public class Student implements Cloneable, Serializable {
    String name;
    int age;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }
    @Override
    protected Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
}

        // 序列化一个对象
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream("student.obj"));
        objectOutputStream.writeObject(student);
        objectOutputStream.close();

        // 反序列化
        ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream("student.obj"));
        Student student5 = (Student) objectInputStream.readObject();
        objectInputStream.close();