2006年11月9日
轉(zhuǎn)自：
http://www.j2medev.com/code/j2se/language/200602/1343.html
import?
java.io.FileInputStream;
import?
java.io.FileOutputStream;
import?
java.io.ObjectInputStream;
import?
java.io.ObjectOutputStream;
import?
java.io.Serializable;
public?class?
CardReader?
{
??
public?static?
void?
main
(
String
[]?
args
)?{
????
Card3?card?=?
new?
Card3
(
12
,?Card3.SPADES
)
;
????
System.out.println
(
"Card?to?write?is:?"?
+?card
)
;
????
try?
{
??????
FileOutputStream?out?=?
new?
FileOutputStream
(
"card.out"
)
;
??????
ObjectOutputStream?oos?=?
new?
ObjectOutputStream
(
out
)
;
??????
oos.writeObject
(
card
)
;
??????
oos.flush
()
;
????
}?
catch?
(
Exception?e
)?{
??????
System.out.println
(
"Problem?serializing:?"?
+?e
)
;
????
}
????
Card3?acard?=?
null
;
????
try?
{
??????
FileInputStream?in?=?
new?
FileInputStream
(
"card.out"
)
;
??????
ObjectInputStream?ois?=?
new?
ObjectInputStream
(
in
)
;
??????
acard?=?
(
Card3
)?(
ois.readObject
())
;
????
}?
catch?
(
Exception?e
)?{
??????
System.out.println
(
"Problem?serializing:?"?
+?e
)
;
????
}
????
System.out.println
(
"Card?read?is:?"?
+?acard
)
;
??
}
}
class?
Card3?
implements?
Serializable?
{
??
private?
int?
suit?=?UNASSIGNED;
??
private?
int?
number?=?UNASSIGNED;
??
public?final?static?
int?
UNASSIGNED?=?-
1
;
??
public?final?static?
int?
DIAMONDS?=?
1
;
??
public?final?static?
int?
CLUBS?=?
2
;
??
public?final?static?
int?
HEARTS?=?
3
;
??
public?final?static?
int?
SPADES?=?
4
;
??
public?final?static?
int?
ACE?=?
1
;
??
public?final?static?
int?
KING?=?
13
;
??
public?
Card3
(
int?
number,?
int?
suit
)?{
????
if?
(
isValidNumber
(
number
))?{
??????
this
.number?=?number;
????
}?
else?
{
??????
//Error
????
}
????
if?
(
isValidSuit
(
suit
))?{
??????
this
.suit?=?suit;
????
}?
else?
{
??????
//Error
????
}
??
}
??
public?
int?
getSuit
()?{
????
return?
suit;
??
}
??
public?
int?
getNumber
()?{
????
return?
number;
??
}
??
public?static?
boolean?
isValidNumber
(
int?
number
)?{
????
if?
(
number?>=?ACE?&&?number?<=?KING
)?{
??????
return?true
;
????
}?
else?
{
??????
return?false
;
????
}
??
}
??
public?static?
boolean?
isValidSuit
(
int?
suit
)?{
????
if?
(
suit?>=?DIAMONDS?&&?suit?<=?SPADES
)?{
??????
return?true
;
????
}?
else?
{
??????
return?false
;
????
}
??
}
??
public?
boolean?
equals
(
Object?obj
)?{
????
if?
(
obj?
instanceof?
Card3
)?{
??????
Card3?card?=?
(
Card3
)?
obj;
??????
if?
(
card.getNumber
()?
==?
this
.number?&&?card.getSuit
()?
==?
this
.suit
)?{
????????
return?true
;
??????
}?
else?
{
????????
return?false
;
??????
}
????
}?
else?
{
??????
return?false
;
????
}
??
}
??
public?
int?
hashCode
()?{
????
return?
number?*?suit;
??
}
??
public?
String?toString
()?{
????
return?
numberToString
(
this
.number
)?
+?
"?of?"?
+?suitToString
(
this
.suit
)
;
??
}
??
public?static?
String?numberToString
(
int?
number
)?{
????
String?result?=?
""
;
????
switch?
(
number
)?{
????
case?
ACE:
??????
result?=?
"Ace"
;
??????
break
;
????
case?
2
:
??????
result?=?
"Two"
;
??????
break
;
????
case?
3
:
??????
result?=?
"Three"
;
??????
break
;
????
case?
4
:
??????
result?=?
"Four"
;
??????
break
;
????
case?
5
:
??????
result?=?
"Five"
;
??????
break
;
????
case?
6
:
??????
result?=?
"Six"
;
??????
break
;
????
case?
7
:
??????
result?=?
"Seven"
;
??????
break
;
????
case?
8
:
??????
result?=?
"Eight"
;
??????
break
;
????
case?
9
:
??????
result?=?
"Nine"
;
??????
break
;
????
case?
10
:
??????
result?=?
"Ten"
;
??????
break
;
????
case?
11
:
??????
result?=?
"Jack"
;
??????
break
;
????
case?
12
:
??????
result?=?
"Queen"
;
??????
break
;
????
case?
KING:
??????
result?=?
"King"
;
??????
break
;
????
case?
UNASSIGNED:
??????
result?=?
"Invalid?Number"
;
??????
break
;
????
}
????
return?
result;
??
}
??
public?static?
String?suitToString
(
int?
suit
)?{
????
String?result?=?
""
;
????
switch?
(
suit
)?{
????
case?
DIAMONDS:
??????
result?=?
"Diamonds"
;
??????
break
;
????
case?
CLUBS:
??????
result?=?
"Clubs"
;
??????
break
;
????
case?
HEARTS:
??????
result?=?
"Hearts"
;
??????
break
;
????
case?
SPADES:
??????
result?=?
"Spades"
;
??????
break
;
????
case?
UNASSIGNED:
??????
result?=?
"Invalid?Suit"
;
??????
break
;
????
}
????
return?
result;
??
}
}
接口 java.io.Serializable
- public interface Serializable
實(shí)現(xiàn) java.io.Serializable 接口的類是可序列化的。沒(méi)有實(shí)現(xiàn)此接口的類將不能使它們的任一狀態(tài)被序列化或逆序列化。序列化類的所有子類本身都是可序列化的。這個(gè)序列化接口沒(méi)有任何方法和域，僅用于標(biāo)識(shí)序列化的語(yǔ)意。
允許非序列化類的子類型序列化，子類型可以假定負(fù)責(zé)保存和恢復(fù)父類型的公有的、保護(hù)的和(如果可訪問(wèn))包的域的狀態(tài)。只要該類(擴(kuò)展)有一個(gè)無(wú)參構(gòu)造子，可初始化它的狀態(tài)，那么子類型就可承擔(dān)上述職責(zé)。在這種情況下申明一個(gè)可序列化的類是一個(gè)錯(cuò)誤。此錯(cuò)誤將在運(yùn)行時(shí)被檢測(cè)。
在逆序列化期間，將使用非序列化類的公用的或保護(hù)的無(wú)參構(gòu)造子對(duì)它的域進(jìn)行初始化。可序列化子類必須能訪問(wèn)父類的無(wú)參構(gòu)造子。它的所有域?qū)南鄳?yīng)流中被恢復(fù)。
當(dāng)遍歷一個(gè)圖象時(shí)，很可能遇到一個(gè)不支持序列化接口的對(duì)象。此時(shí)將拋出 NotSerializableException 異常，且標(biāo)識(shí)該非序列化對(duì)象類。
在序列化處理過(guò)程中需要特定句柄的類，必須使用如下這些恰當(dāng)?shù)臉?biāo)記實(shí)現(xiàn)特定的方法：
private void writeObject(java.io.ObjectOutputStream out)
throws IOException
private void readObject(java.io.ObjectInputStream in)
throws IOException, ClassNotFoundException;
writeObject 方法負(fù)責(zé)寫特定類的對(duì)象的狀態(tài)，以至相應(yīng)的 readObject 方法能恢復(fù)它。 通過(guò)調(diào)用 out.defaultWriteObject 可激活保存對(duì)象域的缺省機(jī)制。此方法不必關(guān)心狀態(tài)是屬于它的父類還是子類。 使用 writeObject 方法或基本類型支持的 DataOutput 方法將每個(gè)域的狀態(tài)保存到 ObjectOutputStream 中。
readObject 方法負(fù)責(zé)從此流中讀取并恢復(fù)類的域。它可能調(diào)用 in.defaultReadObject 方法來(lái)調(diào)用該對(duì)象的非靜態(tài)和非暫時(shí)的域的缺省恢復(fù)機(jī)制。 defaultReadObject 方法使用該流中的信息，用當(dāng)前對(duì)象中的已命名域分配保存在流中該對(duì)象的相應(yīng)域。當(dāng)類已改進(jìn)增加了新域時(shí)，這個(gè)接口也做相應(yīng)處理。此方法不必關(guān)心狀態(tài)是屬于它的父類還是子類。 使用 writeObject 方法或基本類型支持的 DataOutput 方法將每個(gè)域的狀態(tài)保存到 ObjectOutputStream 中。