四种创建对象的方法

原文链接：https://my.oschina.net/u/2385466/blog/547054

(1) 用new语句创建对象，这是最常见的创建对象的方法。
(2) 运用反射手段,调用java.lang.Class或者java.lang.reflect.Constructor类的newInstance()实例方法。
(3) 调用对象的clone()方法。
(4) 运用反序列化手段，调用java.io.ObjectInputStream对象的 readObject()方法。

一.用new语句创建对象
Java代码

User user = new User() 

二.运用反射手段
(1)调用java.lang.Class.newInstance()
Java代码

Class.forName(classname).newInstance()  
Wife wife = (Wife) Class.forName("com.java.clone.Wife").newInstance(); 

(2)调用java.lang.reflect.Constructor类的newInstance()
Java代Constructor constructor = Wife.class.getDeclaredConstructor(int.class,String.class);
Wife wife = (Wife) constructor.newInstance(1,”nihao”); .调用对象的clone()方法
详情参考：http://ncs123.iteye.com/blog/1775631

Java代码

Wife wife = new Wife(1,"wang");  
Wife wife2 = null;  
wife2 = (Wife) wife.clone();//运用clone()方法产生新对象 

四.运用反序列化手段
被序列化的对象必须implements Serializable
Java代码

public class BeanUtil {  

    @SuppressWarnings("unchecked")  
    public static <T> T cloneTo(T src) throws RuntimeException {  
        ByteArrayOutputStream memoryBuffer = new ByteArrayOutputStream();  
        ObjectOutputStream out = null;  
        ObjectInputStream in = null;  
        T dist = null;  

        try {  
            out = new ObjectOutputStream(memoryBuffer);  
            out.writeObject(src);  
            out.flush();  
            in = new ObjectInputStream(new ByteArrayInputStream(  
                    memoryBuffer.toByteArray()));  
            dist = (T) in.readObject();  

        } catch (Exception e) {  
            throw new RuntimeException(e);  
        } finally {  
            if (out != null)  
                try {  
                    out.close();  
                    out = null;  
                } catch (IOException e) {  
                    throw new RuntimeException(e);  
                }  
            if (in != null)  
                try {  
                    in.close();  
                    in = null;  
                } catch (IOException e) {  
                    throw new RuntimeException(e);  
                }  
        }  

        return dist;  
    }  

    public static void main(String[] args){  
        Husband husband = new Husband(1);  
        Wife wife = new Wife(1,"jin");  
        husband.setWife(wife);  
        Husband husband2 = cloneTo(husband);//运用反序列生成了一个对象 
    }  
}

转载于:https://my.oschina.net/u/2385466/blog/547054

标签：java,Wife,newInstance,创建对象,new,null,方法,四种,out
来源： https://blog.csdn.net/chongfei7119/article/details/100802421