2011-2-26 Java 创建新instance的可能方式
无聊总结1.使用 new 关键字;
Object obj = new Object();
2.Cloneable
必须实现Cloneable 接口，并且实现 clone方法（直接套用jdk的）
3.Class.forName
只能适用于无参构造函数（这也是很多框架要求无参构造函数的原因）
4.使用反射 Constructor
比较灵活的构造，各种参数可以传入
5.反序列化
必须实现序列化接口Serializable， 最好显示声明serialVersionUID
举例的class
package com.maneco.art;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.io.Serializable;import java.lang.reflect.Constructor;import java.lang.reflect.InvocationTargetException;public class SerializClass implements Serializable, Cloneable {private static final long serialVersionUID = 1L;String name = "default";@Overridepublic String toString() {return super.toString() + "name: " + name;}@Overrideprotected Object clone() throws CloneNotSupportedException {return super.clone();}public static void main(String[] args) {ObjectOutputStream oos = null;ObjectInputStream ois =null;try {// #0 newSerializClass obj = new SerializClass();// #1 cloneableSerializClass obj0 = (SerializClass) obj.clone();obj0.name = "Cloneable";// #2 class for nameClass clazz = Class.forName("com.maneco.art.SerializClass");SerializClass obj1 = (SerializClass) clazz.newInstance();obj1.name = "ClassForName";// #3 reflect SerializClass obj2 = null;Constructor[] cs = SerializClass.class.getConstructors();for (Constructor c : cs) {obj2 = (SerializClass) c.newInstance(null);}obj2.name = "Reflect";// #4 deserializeoos = new ObjectOutputStream(new FileOutputStream("Object.txt"));oos.writeObject(obj2);oos.flush();ois =new ObjectInputStream(new FileInputStream("Object.txt"));SerializClass obj3 = (SerializClass) ois.readObject();// printSystem.out.println(obj);System.out.println(obj0);System.out.println(obj1);System.out.println(obj2);System.out.println(obj3);} catch (ClassNotFoundException e) {e.printStackTrace();} catch (IllegalArgumentException e) {e.printStackTrace();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} catch (CloneNotSupportedException e) {e.printStackTrace();} finally {if (null != oos) {try {oos.close();} catch (IOException e) {e.printStackTrace();}} if (null != ois) {try {ois.close();} catch (IOException e) {e.printStackTrace();}}}}}
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