java实例化对象的五种方式

1、用new语句创建对象，这是最常见的创建对象的方法。

Student student = new Student();

2、通过工厂方法返回对象，如：String str = String.valueOf(23); 

public interface Factory{
Product createProduct();
public class ConcreateFactory implements Factory{
}
public Product createProduct(){
return new ConcreateProduct();}
public class ConcreateProduct implements Product{}
}public interface Product{}
private Factory factory;
public class Client{
this.factory = factory;
public Client(Factory factory){}
Product product = factory.createProduct();
public void dosomething(){}
Client client = new Client(new ConcreateFactory());
public static void main(String[] args){client.dosomething();}
}

3、运用反射手段,调用java.lang.Class或者java.lang.reflect.Constructor类的newInstance()实例方法。如：Object obj = Class.forName("java.lang.Object").newInstance(); 

c1 = Class.forName('com.ghgj.reflect.Student');Student student3 = (Student)c1.newInstance();

4、调用对象的clone()方法。

Student student2 = (Student) student.clone();

5、通过I/O流（包括反序列化），如运用反序列化手段，调用java.io.ObjectInputStream对象的 readObject()方法。

ObjectOutputStream out = new ObjectOutputStream (new FileOutputStream("C:/student.txt"));out.writeObject(student);out.close();ObjectInputStream in = new ObjectInputStream(new FileInputStream("C:/student.txt"));Student student4 = (Student)in.readObject();in.close();