作者qrtt1 (愚者)
看板java
标题Re: [心得] 序列化的小细节
时间Thu Oct 26 17:56:52 2006
: 想当然尔：
: System.out.println(a.b == b);
: System.out.println(a.b.a == a);
: System.out.println(b.a == a);
: System.out.println(b.a.b == b);
: 印出来的是：
: true
: true
: true
: true
: 此时：
: System.out.println(a.b == b);
: System.out.println(a.b.a == a);
: System.out.println(b.a == a);
: System.out.println(b.a.b == b);
: 印出来的是：
: false
: true
: false
: true
Dear Pao,
请记得比较物件是用equals方法，不是用==
对於任何物件的制作我们都有责任覆写hashCode与equals
心有余力再写一下toString
另外，Serialization的目的是保持同样"内容的物件"
我可以有千百个内容相同的物件，但他们的记忆体位置都不同
=========================================================================
import java.io.Serializable;
public class A implements Serializable {
String sign;
public A(String s) {
this.sign = s;
}
public String toString(){
return this.sign;
}
public B b;
}
import java.io.Serializable;
public class B implements Serializable {
String sign;
public A a;
public String toString(){return this.sign;}
public B(String s){
this.sign=s;
}
}
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
public class NN {
A a;
B b;
public NN() {
a = new A("A@");
b = new B("B@");
a.b = b;
b.a = a;
}
public void makeObjectFile() throws IOException{
FileOutputStream fos = new FileOutputStream("a.object");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(a);
oos.close();
fos = new FileOutputStream("b.object");
oos = new ObjectOutputStream(fos);
oos.writeObject(b);
oos.close();
}
public Object readObjectFile(String name) throws IOException,
ClassNotFoundException{
FileInputStream fis = new FileInputStream(name);
ObjectInputStream ois = new ObjectInputStream(fis);
Object o = ois.readObject();
ois.close();
return o;
}
public static void main(String[] args) throws IOException,
ClassNotFoundException {
NN n = new NN();
n.makeObjectFile();
B b = (B) n.readObjectFile("b.object");
A a = (A) n.readObjectFile("a.object");
System.out.println(b);
System.out.println(b.a);
System.out.println(a.b);
System.out.println(a);
}
}
Result:
B@
A@
B@
A@
--
btw. 偷打一下广告
[分享] 实作用serialization实现deep clone
http://www.javaworld.com.tw/jute/post/view?
bid=35&id=154519&sty=3&keywords=clone
(
http://tinyurl.com/y8tckq)
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 163.26.34.20
※ 编辑: qrtt1 来自: 163.26.34.20 (10/26 17:58)
※ 编辑: qrtt1 来自: 163.26.34.20 (10/26 17:58)