Java对象创建的几种方式总结

Student student1 = new Student();

Student student2 = Student.class.newInstance();

Constructor student3 = Constructor.class.newInstance();

ObjectInputStream ois = new ObjectInputStream(new FileInputStream(FILE_NAME));
// 5、使用反序列化创建对象
Object student5 = ois.readObject();

package com.effective.chapter2.other;
 
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
 
import java.io.Serializable;
 
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Student implements Cloneable, Serializable {
    private String name;
    private Integer age;
 
    @Override
    public Student clone() {
        try {
            Student clone = (Student) super.clone();
            // TODO: copy mutable state here, so the clone can't change the internals of the original
            return clone;
        } catch (CloneNotSupportedException e) {
            throw new AssertionError();
        }
    }
}

package com.effective.chapter2.other;
 
import java.io.*;
import java.lang.reflect.Constructor;
 
public class CreateObjectTest {
 
    private static final String FILE_NAME = "student.obj";
 
    public static void main(String[] args) throws InstantiationException, IllegalAccessException, IOException {
 
        // 1、使用new关键字创建对象
        Student student1 = new Student();
        System.out.println("使用new关键字创建对象：" + student1);
 
        // 2、使用Class类的newInstance()方法创建对象
        Student student2 = Student.class.newInstance();
        System.out.println("使用Class类的newInstance()方法创建对象：" + student2);
 
        // 3、使用Constructor类的newInstance()方法创建对象
        Constructor student3 = Constructor.class.newInstance();
        System.out.println("使用Constructor类的newInstance()方法创建对象：" + student3);
 
        // 4、使用clone()方法创建对象
        Student student4 = student2.clone();
        System.out.println("使用clone()方法创建对象：" + student4);
 
        try {
            // Java序列化是指把Java对象转换为字节序列的过程，而Java反序列化是指把字节序列恢复为Java对象的过程；
            // 序列化对象
            ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(FILE_NAME));
            oos.writeObject(student1);
 
            ObjectInputStream ois = new ObjectInputStream(new FileInputStream(FILE_NAME));
            // 5、使用反序列化创建对象
            Object student5 = ois.readObject();
            System.out.println("使用反序列化创建对象：" + student5);
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        }
    }
}