[褰㈡垚]
Singleton Pattern 涓轟粈涔堜細(xì)鍑虹幇?鍦ㄦ垜浠蔣浠跺紑鍙戝拰鏋舵瀯涓?緇忓父閬囧埌榪欐牱鐨勬儏褰?鎴戜滑闇€瑕佷竴涓被鍙兘涓斾粎鑳戒駭鐢熶竴涓疄渚?.姣斿琛ㄧず涓€鍙拌綆楁満鐨勭被,琛ㄧず緋葷粺璁懼畾鐨勭被鎴栬€呮槸琛ㄧず紿楀彛鐨勭被,榪樻湁涓轟簡鑺傜害璧勬簮,鍙浜х敓涓€涓疄渚?.
濡備綍鏋勯€犺繖縐嶆儏褰?Singleton妯″紡緇欐垜涓€涓柟妗?
[浠ｇ爜紺轟緥]
紼嬪簭鍒楄〃
|
鍚嶇О |
璇存槑 |
|
Singleton |
鍙湁涓€涓璞″疄渚嬬殑綾?/p> |
|
Main |
嫻嬭瘯鐢ㄧ殑綾?/p> |
[UML鍥綸
[紺轟緥浠ｇ爜鍜岀被鐨勮癄閲奭
1 package singleton;
2
3 public class Singleton {
4 private static Singleton singleton = new Singleton();
5
6 private Singleton() {
7 System.out.println("Create instance...");
8 }
9
10 public static Singleton getInstance() {
11 return singleton;
12 }
13 }
14
2
3 public class Singleton {
4 private static Singleton singleton = new Singleton();
5
6 private Singleton() {
7 System.out.println("Create instance...");
8 }
9
10 public static Singleton getInstance() {
11 return singleton;
12 }
13 }
14
Singleton Class:
1.璇ョ被鍙兘浜х敓涓€涓璞″疄渚?br />
2.鎶婅綾葷殑鐨剆ingleton灞炴€ц瀹氫負(fù)static鍐嶄互Singleton;綾葷殑瀵硅薄瀹炰緥榪涜鍒濆鍖?榪欎釜鍒濆鍖栫殑榪囩▼浠呭姞杞絊ington綾葷殑鏃跺€欒皟鐢ㄤ竴嬈?(Line4)
3.鎶奡ingleton 綾葷殑鏋勯€犲嚱鏁伴檺瀹氫負(fù)private,鐩殑鏄負(fù)浜嗛槻姝粠闈濻ingleton綾?鍏朵粬綾?璋冪敤鏋勯€犲嚱鏁版潵浜х敓瀹炰緥,濡傛灉閫氳繃new鏂瑰紡鏉ヤ駭鐢烻ingleton瀹炰緥,浼?xì)鍑虹幇缂栬瘧閿欒?榪欐牱鍋氭槸涓轟簡淇濋櫓宸辮.(Line6)
4.瑕佸緱鍒癝ingleton瀹炰緥鐨勫敮涓€鏂規(guī)硶灝辨槸璋冪敤綾婚潤鎬佹柟娉昰etInstance().榪欎釜鍚嶅瓧鍙互闅忎究鍙?鍙鏂逛究鐞嗚В灝辮.(Line 10)
1 package singleton;
2
3 public class Main {
4
5 public static void main(String[] args) {
6 System.out.println("Start");
7 Singleton obj1 = Singleton.getInstance();
8 Singleton obj2 = Singleton.getInstance();
9 if(obj1 == obj2){
10 System.out.println("obj1鍜宱bj2鏄悓涓€鍊嬪皪璞″渚?/span>");
11 }else{
12 System.out.println("obj1鍜宱bj2涓嶆槸鍚屼竴鍊嬪皪璞″渚?/span>");
13 }
14 System.out.println("End");
15 }
16 }
17
2
3 public class Main {
4
5 public static void main(String[] args) {
6 System.out.println("Start");
7 Singleton obj1 = Singleton.getInstance();
8 Singleton obj2 = Singleton.getInstance();
9 if(obj1 == obj2){
10 System.out.println("obj1鍜宱bj2鏄悓涓€鍊嬪皪璞″渚?/span>");
11 }else{
12 System.out.println("obj1鍜宱bj2涓嶆槸鍚屼竴鍊嬪皪璞″渚?/span>");
13 }
14 System.out.println("End");
15 }
16 }
17
Main Class
1.璇ョ被鏄祴璇曠▼搴?
2.紼嬪簭閫氳繃getInstance()鏂瑰紡浜х敓涓や釜obj1鍜宱bj2瀹炰緥.(Line 7,Line 8)
3.閫氳繃ojb1= =ojb2琛ㄨ揪寮忔潵紜畾涓や釜瀵硅薄鏄惁鐩稿悓,鍒ゅ畾鏄惁浜х敓浜哠ingleton鐨勭浜屼釜紺轟緥.(Line9-12)
鎵ц緇撴灉鍚箟:
1. 鐨勭‘濡傛,obj1鍜宱bj2鏄疭ingleton綾葷殑鍚屼竴涓笖鍞竴鐨勫璞″疄渚?
2.褰撶▼搴忔墽琛屽悗,絎竴嬈¤皟鐢╣etInstance鐨勬椂鍊欎細(xì)鍒濆鍖朣ingleton綾?鍚屾椂涔熶細(xì)鍒濆鍖杝tatic瀛楁,涔熷悓鏃朵駭鐢熶駭鐢熶簡涓€涓敮涓€瀵硅薄瀹炰緥.
[鎷撳睍鎬濊€僝
濡備笅鐨勫彟涓€涓€涓崟渚嬫ā寮忕殑紼嬪簭鏈変粈涔堥殣鎮(zhèn)?
1 package singleton;
2
3 public class Singleton2 {
4
5 private static Singleton2 singleton = null;
6
7 private Singleton2(){
8 System.out.println("宸茬敘鐢熷皪璞″渚?/span>");
9 }
10 public static Singleton2 getInstance(){
11 if(singleton == null){
12 singleton = new Singleton2();
13 }
14 return singleton;
15 }
16
17 }
18
2
3 public class Singleton2 {
4
5 private static Singleton2 singleton = null;
6
7 private Singleton2(){
8 System.out.println("宸茬敘鐢熷皪璞″渚?/span>");
9 }
10 public static Singleton2 getInstance(){
11 if(singleton == null){
12 singleton = new Singleton2();
13 }
14 return singleton;
15 }
16
17 }
18
[瑙ｇ瓟]
褰撳綰跨▼鍚屾椂璋冪敤Singleton2.getInstance()鏂規(guī)硶鏃訛紝鍙兘浼?xì)漶旂敓澶氫釜瀵硅薄瀹炰緥锛屼緥濡?br />
public class Main extends Thread{
public static void main(String[] args) {
System.out.println("Starts."); new Main("A").start(); new Main("B").start(); new Main("C").start(); System.out.println("End.");
} public void run(){ Singleton2 obj = Singleton2.getInstance(); System.out.println(getName()+": obj ="+obj); } public Main(String name){ super(name); }
}
public class Singleton2 { private static Singleton2 singleton2 = null; private Singleton2(){ System.out.println("宸蹭駭鐢熷璞″疄渚?/span>"); solwDown(); } public static Singleton2 getInstance(){ if(singleton2 == null){ singleton2 = new Singleton2(); } return singleton2; } private void solwDown(){ try{ Thread.sleep(1000); }catch(InterruptedException e){ e.printStackTrace(); } }}鎵ц緇撴灉錛?br />
Start.
End.
宸蹭駭鐢熷璞″疄渚?
宸蹭駭鐢熷璞″疄渚?
宸蹭駭鐢熷璞″疄渚?
B: obj = Singleton2#2a9348
C: obj = Singleton2#b91134
A: obj = Singleton2#e343l12
錛?鏇挎崲涓篅錛?br />
涔嬫墍浠ヤ細(xì)鐭ラ亾榪欑鎯呭喌鏄洜涓篿f(singleton = = null){ singleton = new Singleton2(); }鍒ゆ柇涓嶅涓ヨ皚鐨勫鑷淬€?br /> 鍒╃敤: singleton == null 鍒ゆ柇涓虹┖鍚庡幓鎵цnew Singleton2()涔嬪墠錛屽彲鑳戒細(xì)鏈夊叾浠栫嚎紼嬫潵鎶㈠厛鍒ゆ柇琛ㄨ揪寮弒ingleton == null錛屼粠鑰屽張鎵ц涓€閬嶅垱寤哄疄渚嬬殑鎿嶄綔銆?br />
瑙ｅ喅鍔炴硶錛?br /> 緇檊etInstance()鏂規(guī)硶娣誨姞Synchronized淇グ絎︼紝鍗沖彲淇敼鎴愮嚎紼嬪畨鍏ㄤ弗璋ㄧ殑鍗曚緥妯″紡銆?br />
public class Singleton2 {
private static Singleton2 singleton = null;
private Singleton2() {
System.out.println("宸蹭駭鐢熷璞″疄渚?/span>");
solwDown();
}
public static synchronized Singleton2 getInstance() {
if (singleton == null) {
singleton = new Singleton2();
}
return singleton;
}
private void solwDown() {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
private static Singleton2 singleton = null;
private Singleton2() {
System.out.println("宸蹭駭鐢熷璞″疄渚?/span>");
solwDown();
}
public static synchronized Singleton2 getInstance() {
if (singleton == null) {
singleton = new Singleton2();
}
return singleton;
}
private void solwDown() {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
]]>
璇濊"宸ユ鍠勫叾宸ラ渶鍒╁叾鍣?,鏈変簡濂界殑宸ュ叿,濂界殑琛ㄨ揪鏂瑰紡,鑳界粰鎴戜滑鐨勫伐浣滃彉寰楃畝鍗曡€屼紭闆?
涓轟簡鏇村ソ鐨勮瑙ｈ璁℃ā寮?鏂逛究鐞嗚В,闇€瑕佽繍鐢ㄤ竴縐嶅緩妯¤璁¤璦€----UML.
UML(UML:Unified Modeling Language),鍗崇粺涓€寤烘ā璇█,鐢ㄦ潵瀵硅蔣浠跺瘑闆嗙郴緇熻繘琛屾弿榪般€佹瀯閫犮€佽鍖栧拰鏂囨。緙栧埗鐨勪竴縐嶈璦€.榪欐槸姒傚康,涓嶅ソ鐞嗚В.
UML鐨勪綔鐢?鎵撲釜姣旀柟:涓€孌墊弿鍐欒糠浜烘搗婊╅鏅殑鏂囧瓧鍜屼竴騫呮弿緇樻搗婊╅鏅殑娌圭敾,鍘葷湅榪欎袱浠朵笢瑗跨殑浜?鏈夌殑浜哄彲鑳借兘璇繪噦鏂囧瓧(鍙兘鏄壒瀹氱殑璇█),鏈夌殑涓嶈瀛?鎵€浠ュ茍涓嶆槸鎵€鏈夌殑浜鴻兘鐪嬫噦鏂囧瓧琛ㄨ揪鐨勫唴瀹?浣嗘槸鎵€鏈夌殑浜洪兘鑳借鎳傛補(bǔ)鐢繪墍琛ㄧ幇鍑烘潵鐨勫惈涔?娌圭敾琛ㄨ揪鍐呭鐨勭洿鎺?褰㈣薄,涓板瘜鐗規(guī)€у氨綾誨瀷UML鍦ㄦ弿鍙欒蔣浠剁粨鏋勮繃紼嬩腑鐨勪綔鐢?
鍦ㄨ蔣浠墮」鐩腑,涓€鑸湁鍑犱釜瑙掕壊:鐢ㄦ埛(User),鏋舵瀯璁捐甯?orPM, SA),紼嬪簭鍛?PG)
鐢ㄦ埛:
涔熻涓嶆噦璁＄畻鏈?涔熶笉鎳傜紪紼嬭璦€,浣嗘槸鎳傝涓氫笟鍔?璇ヨ蔣浠剁殑鍔熻兘闇€姹?
紼嬪簭鍛?br /> 鎳傝綆楁妧鏈?鎳傜紪紼嬭璦€.浣嗘槸涓嶅お浜嗚В琛屼笟閫昏緫.闇€瑕佹妸瀹㈡埛鐨勪笟鍔″簲鐢ㄩ渶姹傝漿鍙樹負(fù)紼嬪簭浠ｇ爜,
鏋舵瀯璁捐甯?br /> 璧勬繁鐨勮涓氭灦鏋勮璁″笀搴旇鍏鋒湁涓€瀹氱殑琛屼笟鐭ヨ瘑,鏃㈣兘鍚噦瀹㈡埛鐨勪笟鍔￠渶姹?鍙堣兘鐭ラ亾鎬庝箞鍛婅瘔紼嬪簭鍛樺幓鐢ㄤ唬鐮佸疄鐜?
鏋舵瀯璁捐甯堝湪鍓嶄袱鑰呬氦嫻佷腑璧峰埌鎵垮墠鍚悗鐨?涓棿浣?浣滅敤.UML灝辨槸閲囩敤鍥懼艦鍖栫殑褰㈠紡鏉ヨ〃杈炬灦鏋勫拰璁捐.鎴愪負(fù)浜嗗緩妯¤璁＄殑閫氱敤鐨勮璁℃爣鍑?.
UML鍥捐淇℃伅浜ゆ祦鍙樺緱綆€鍗?br />
[UML鍩虹]
1.綾葷殑灞傜駭鍏崇郴
UML涓殑綾誨浘鏄竴縐嶅彲琛ㄧず涓€緇勭被,瀵硅薄瀹炰緥鍜屾帴鍙ｄ箣闂寸殑闈欐€佸叧緋誨浘.
濡傚浘鐨刄ML綾誨浘琛ㄨ揪浜嗕笂闈唬鐮佺殑鍚箟,
綾諱箣闂寸殑鍏崇郴鏈夊洓縐?渚濊禆,娉涘寲,瀹炵幇鑱氶泦,緇勬垚.鍏蜂綋鐨刄ML瀹炰緥鍙互鍙俇ML鍩虹.
2.鎺ュ彛鍜屽疄鐜?br />
瀹炵幇鎺ュ彛鐨刄ML紺轟緥濡備笅:
interface Printable {
abstract void print();
}
abstract void print();
}
public class PrintClass implements Printable {
public void print() {
// how to print
}
}
public void print() {
// how to print
}
}
鎺ュ彛,鎶借薄,瀹炵幇,緇ф壙鍦ㄨ璁℃ā寮忎腑琚箍娉涚殑浣跨敤,榪欎篃鏄疧OD鐨勪紭鍔挎墍鍦?緹庡鎵€鍦?
榪欓噷鍙婦鍑轟簡鍑犱釜綆€鍗曟儏褰?璁╁ぇ瀹舵湁涓劅鎬х殑浜嗚В,鍏蜂綋鐨勬儏褰㈠湪璇村叿浣撶殑璁捐妯″紡鐨勬椂鍊欏湪閽堝鎬х殑璇存槑,鍏堜笉鐢ㄥ紕閭ｄ箞澶?閭ｄ箞鏉?鑳藉紑濮嬩笅涓€姝ュ氨瓚沖.
綾諱箣闂寸殑鍏崇郴
綾諱箣闂寸殑鍏崇郴鏈?縐嶏紝鍏寵仈 渚濊禆 鑱氶泦 娉涘寲 瀹炵幇
]]>
鏃ユ湡:2007-06-05
棣栧厛璇磋鍐欒繖緋誨垪鐨勬枃绔犵殑鎯蟲硶錛岀洰鐨勫湪浜?
1.鑷繁涔熷湪鐮斾範(fàn)璁捐妯″紡,閫氳繃鍦ㄨ嚜鎴戞€葷粨鐨勮繃紼嬩腑,甯屾湜鑳藉璁捐妯″紡澶氫竴鐐規(guī)繁鍒葷悊瑙?br> 2.甯屾湜緇欑湅鍒拌繖緋誨垪鏂囩珷鐨勬湅鍙嬩竴鐐瑰璁捐妯″紡瀛︿範(fàn)鐨勫府鍔?鐗瑰埆鏄璁捐妯″紡鐨勫垵瀛﹁€呰兘璧峰埌"寮曡繘闂?鐨勬晥鏋?
濡傛灉浠ヤ笂鐨勪綔鐢ㄨ兘璧峰埌鍝€曚竴鐐?鎴戜篃嬈ｉ椈鑰岀瑧浜?
璁捐妯″紡(Design Patterns)鏄粈涔?涓轟粈涔堜細(xì)鍑虹幇璁捐妯″紡?鍋氳繃寮€鍙戦」鐩殑鏈嬪弸鍙兘閮介亣鍒拌繃,涓€涓棶棰樹細(xì)鍦ㄤ竴涓」鐩垨鑰呭涓」鐩腑閲嶅鍑虹幇,鑰岀浉搴旂殑瑙ｅ喅鏂規(guī)閮芥槸綾諱技鐩稿悓,鐩稿簲浠ｇ爜鐨勫疄鐜頒篃鏄ぇ鍚屽皬寮?涓轟粈涔堟垜浠笉鑳藉鐢ㄨ繖浜涜В鍐蟲柟妗?鎴栬€呰鎴戜滑鏄惁鑳戒慨鏀規(guī)垨閲嶆柊鏋勫緩涓€涓嬭璁℃灦鏋勬潵浣垮緱閲嶅鐨勪唬鐮佹洿灝?緇撴瀯鏇村悎鐞? 褰撶劧,榪欎簺鏄彲琛屼笖鏈夊繀瑕佺殑. 姝ゆ椂璁捐妯″紡鐨勫嚭鐜拌鎴戜滑鑼呰垗欏垮紑.
璇村埌璁捐妯″紡,涓嶅緱璋堜竴鏈功<Design Patterns:Element of Resuable Object-Oriented Software),浣滆€呮槸GoF,瀹為檯鏄笁涓漢鍚堣憲鐨?涔嬫墍浠ユ彁鍒拌繖鏈功,鍥犱負(fù)榪欐湰涔︾殑緇忓吀鍦ㄤ簬璇︾粏闃愯堪浜?3縐嶅湪杞歡寮€鍙戣繃紼嬩腑榪愮敤騫挎硾鐨?妯″紡",榪欎竴涓悊蹇電殑鎻愬嚭,緇欓潰鍚戝璞¤璁?OOD)娉ㄥ叆浜嗘柊鐨勮娑?浣撶幇鍑篛OD瓚呰秺闈㈠悜榪囩▼璁捐鐨勪紭鍔挎墍鍦?浠庢璁╃▼搴忓憳鐪嬪緟浠ｇ爜鏈変簡"鍝插鐨勭溂鍏?..
灝卞儚榪欐湰涔﹀畾涔夌殑妯″紡:姣忎釜妯″紡鎻忚堪浜嗕竴涓湪鎴戜滑鍛ㄥ洿涓嶆柇閲嶅鍜屽彂鐢熺殑闂,浠ュ強(qiáng)璇ラ棶棰樿В鍐蟲柟妗堢殑鏍稿績,榪欐牱浣犲氨鑳戒竴嬈″張涓€嬈′嬌鐢ㄨ鏂規(guī)鑰屼笉蹇呭仛閲嶅鍔沖姩.
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瀹炵幇璇█閲囩敤Java,鏄璁℃ā寮忚OOD鎴愪負(fù)杞歡寮€鍙戝巻鍙蹭笂鐨勫厜杈夋洿鍔犵粴鐑?
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