java創(chuàng)建對(duì)象的方式

2019-11-06 06:48:23

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java創(chuàng)建對(duì)象的方式

1、直接new2、通過(guò)反射clazz的newInstance調(diào)用無(wú)參構(gòu)造函數(shù)創(chuàng)建對(duì)象3、通過(guò)反射獲取構(gòu)造函數(shù)直接newInstance創(chuàng)建對(duì)象4、實(shí)現(xiàn)Serializable接口，通過(guò)反系列化創(chuàng)建對(duì)象5、實(shí)現(xiàn)Cloneable接口，覆蓋clone方法，通過(guò)克隆創(chuàng)建對(duì)象package cn.zlz.createobj;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.lang.reflect.Constructor;/** * 創(chuàng)建對(duì)象的方式 * 1、直接new * 2、通過(guò)反射clazz的newInstance調(diào)用無(wú)參構(gòu)造函數(shù)創(chuàng)建對(duì)象 * 3、通過(guò)反射獲取構(gòu)造函數(shù)直接newInstance創(chuàng)建對(duì)象 * 4、實(shí)現(xiàn)Serializable接口，通過(guò)反系列化創(chuàng)建對(duì)象 * 5、實(shí)現(xiàn)Cloneable接口，覆蓋clone方法，通過(guò)克隆創(chuàng)建對(duì)象 * */public class Main { public static void main(String[] args) { // 通過(guò)構(gòu)造函數(shù)直接new Person person = new Person(); System.out.PRintln(person); // 通過(guò)反射創(chuàng)建對(duì)象 createByReflect(); // 通過(guò)構(gòu)造器反射創(chuàng)建對(duì)象 createByConstructor(); // 通過(guò)序列化創(chuàng)建對(duì)象 createBySerialize(); //通過(guò)克隆創(chuàng)建對(duì)象 createByClone(); } private static void createByClone() { Person person = new Person("wangwu",5); Person clone = person.clone(); System.out.println(clone); } private static void createBySerialize() { try { String filePath = "person.dat"; Person instance = new Person("lizi",4); ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream( filePath)); objectOutputStream.writeObject(instance); ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream(filePath)); Person person = (Person) objectInputStream.readObject(); System.out.println(person); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } private static void createByConstructor() { try { Class<?> clazz = Class.forName("cn.zlz.createobj.Person"); Constructor<?> constructor = clazz.getDeclaredConstructor(String.class, int.class); Person person = (Person) constructor.newInstance("zhangsan", 2); System.out.println(person); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } private static void createByReflect() { try { Class<?> clazz = Class.forName("cn.zlz.createobj.Person"); Person person = (Person) clazz.newInstance(); System.out.println(person); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } }}package cn.zlz.createobj;import java.io.Serializable;public class Person implements Serializable, Cloneable { /** * */ private static final long serialVersionUID = 1L; private String name; private int age; public Person(String name, int age) { super(); this.name = name; this.age = age; } public Person() { super(); } @Override public String toString() { return "Person [name=" + name + ", age=" + age + "]"; } @Override public Person clone() { Person person = null; try { return (Person) super.clone(); } catch (CloneNotSupportedException e) { e.printStackTrace(); } return person; }}

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