鎿呰嚜鏀瑰姩瀹炰緥鐨勭姸鎬侊紝瀹炰緥浼氫撫澶卞畨鍏ㄦ€с€傝繖縐嶆儏鍐靛彲浠ラ€氳繃Java鐨勫叧閿瘝synchronized鏉ヨВ鍐熾€傚澶氫釜浜?br /> 閫氳繃涓€涓猤ate鏃訛紝鍙兘涓€涓釜閫氳繃錛岄偅涔堝彲浠ュ涓嬬殑鏂瑰紡錛?br /> public synchronized void pass(String name){
this.name = name;
}
synchronized鏂規硶鐨勬€ц兘姣旀櫘閫氱殑鏂規硶浣庯紝鎵€浠ラ檷浣庡噺灝戜嬌鐢ㄣ€?br /> JDK涓緢澶氭柟娉曟槸synchronized錛屽彲浠ュ畨鍏ㄤ嬌鐢紝寰堝涓轟簡鎬ц兘鏄病鏈夊悓姝ャ€備負浜嗘彁楂樻€ц兘鍙互鑰冭檻浣跨敤 Immutable Pattern
2.Immutable Pattern 澶氫釜綰跨▼鍏變韓涓€涓疄渚嬶紝浣嗘槸瀹炰緥鐨勭姸鎬佷笉浼氭敼鍙橈紝鍙互鎻愪緵throughput錛屼絾蹇呴』淇濊瘉
涓嶅彉褰紙瀹炰緥鐨勭姸鎬佷笉浼氭敼鍙橈級銆傞渶瑕佷嬌鐢╬rivate錛宖inal絳夋潵鏀寔銆?br /> 3.Guarded Suspension Pattern 澶氫釜綰跨▼鍏變韓涓€涓疄渚嬶紝榪欐牱鐨勮瘽錛屽涓嚎紼嬮兘
鎿呰嚜鏀瑰姩瀹炰緥鐨勭姸鎬侊紝瀹炰緥浼氫撫澶卞畨鍏ㄦ€с€傚綋瀹炰緥鐨勭姸鎬佷笉鎭板綋鏃訛紝灝辮姹傜嚎紼嬬瓑寰呭埌鍚堥€傜殑鐘舵€侊紝浠?#8220;璀︽垝鏉?nbsp; 浠?#8221;鏉ヨ〃紺哄疄渚嬬殑“閫傚綋鐨勭姸鎬?#8221;銆傚鏋滆鎴掓潯浠朵竴鐩翠笉鎴愮珛錛岀嚎紼嬩細姘歌繙絳夊緟涓嬪幓錛屼細浣跨▼搴忎撫澶辯敓鍛芥€с€侸ava 涓敤while寰幆鏉ユ祴璇曡鎴掓潯浠訛紝浣跨敤wait鏂規硶璁╃嚎紼嬬瓑寰咃紝騫朵嬌鐢╪otify/notifyAll閫氱煡璀︽垝鏉′歡鐨勬敼鍙樸€?br /> 媯€ 楠屻€佷慨鏀硅鎴掓潯浠舵槸錛屼細浣跨敤Single Threaded Execution Pattern銆侾attern鐨勪緥瀛愬涓嬶細
public class RequestQueue{
private final LinkedList queue = new LinkedList();
public synchronized Request getRequest(){
while(queue.size() <= 0){ //璀︽垝鏉′歡
try{
wait();
}catch(InterruptedException e){}
}
return (Request)queue.removeFirst();
}
public synchronized void putRequest(Request request){
queue.addLast(request);
notifyAll();
}
}
浠ヤ笂浣跨敤Queue鐨勫鎴風鍜屾湇鍔″櫒浠ｇ爜閲岄潰闈炲父騫插噣錛屾病鏈夊綰跨▼鐨勪笢瑗匡紝浠ｇ爜澶嶇敤鎬у緢濂姐€?br /> 褰撹鎴掓潯浠朵笉鎴愮珛鏃舵兂瑕侀┈涓婇€€鍑猴紝灝變嬌鐢˙alking Pattern
4.Balking Pattern 涓€鐩寸瓑寰呭畨鍏ㄧ殑鏃舵満錛屼細浣跨▼搴忕殑鍝嶅簲鎬ч檷浣庛€侸ava璇█涓紝媯€楠岃鎴掓潯浠舵椂瑕佷嬌鐢╥f璇彞
錛屽綋瑕乥alk鏃訛紝鍙嬌鐢╮eturn閫€鍑烘柟娉曪紝鎴栬€卼hrow鎶涘嚭寮傚父銆?br /> public class Data {
private String filename; //淇敼鏄殑鍚嶅瓧顨?br /> private String content; // 璧勬枡鐨勫唴瀹?br /> private boolean changed; //淇敼鍚庣殑鍐呭榪樻病瀛樺偍鐨勮瘽錛屽€間負true
public Data(String filename, String content) {
this.filename = filename;
this.content = content;
this.changed = true;
}
// 淇敼璧勬枡鍐呭
public synchronized void change(String newContent) {
content = newContent;
changed = true;
}
// 鑻ユ湁璧勬枡淇敼錛屽氨瀛樺偍鍒版尅瀹夐噷
public synchronized void save() throws IOException {
if (!changed) {
System.out.println(Thread.currentThread().getName() + " balks");
return; //娌℃湁灝遍€€鍑?nbsp;
}
doSave();
changed = false;
}
// 瀹為檯璧勬枡鍌ㄥ瓨鍒版尅妗堥噷鐢ㄧ殑鏂規硶
private void doSave() throws IOException {
System.out.println(Thread.currentThread().getName() + " calls doSave, content = " + content);
Writer writer = new FileWriter(filename);
writer.write(content);
writer.close();
}
}
5.Producer-Consumer Pattern 褰揚roducer鍙備笌鑰呬笌Consumer鍙備笌鑰呭鐞嗙殑閫熷害涓嶅悓鏃訛紝閫熷害鎱㈢殑浼氭壇閫熷害蹇殑
鍚庤吙錛岃€岄檷浣庣▼搴忕殑throughput銆傝В鍐崇殑鍔炴硶灝辨槸鍦ㄤ袱鑰呬箣闂達紝鍔犱笂涓戶鐢ㄧ殑Channel鍙備笌鑰呫€傚茍璁〤hannel
鍙備笌鑰呭瓨鏀懼鏉℃暟鎹紝榪欐牱灝卞彲浠ョ紦鍐睵roducer鍜孋onsumer涔嬮棿澶勭悊閫熷害鐨勫樊寮傘€傝繖涓ā寮忎嬌鐢ㄤ簡Guarded
Suspension Pattern銆?br />
public class Table {
private final String[] buffer;
private int tail; /涓嬩竴涓斁put鐨勫湴鏂?
private int head; //涓嬩竴涓斁鐨則ake鍦版柟
private int count; // buffer鍐呯殑铔嬬硶鏁?br /> public Table(int count) {
this.buffer = new String[count];
this.head = 0;
this.tail = 0;
this.count = 0;
}
// 鏀劇疆铔嬬硶
public synchronized void put(String cake) throws InterruptedException {
System.out.println(Thread.currentThread().getName() + " puts " + cake);
while (count >= buffer.length) {
wait();
}
buffer[tail] = cake;
tail = (tail + 1) % buffer.length;
count++;
notifyAll();
}
// 顭濆彇寰楄泲緋?br /> public synchronized String take() throws InterruptedException {
while (count <= 0) {
wait();
}
String cake = buffer[head];
head = (head + 1) % buffer.length;
count--;
notifyAll();
System.out.println(Thread.currentThread().getName() + " takes " + cake);
return cake;
}
}
6.Read-Write Lock Pattern 澶氫釜綰跨▼鍏變韓涓€涓疄渚嬶紝濡傝繘紼嬩箣闂翠笉榪涜鍏變韓鑳℃壇錛屼細涓уけ瀹夊叏鎬с€?br /> 浣嗕嬌鐢⊿ingle Threaded Execution Pattern浼氫嬌紼嬪簭throughput闄嶄綆銆傝В鍐崇殑鏂規硶灝辨槸灝嗘帶鍒秗eader鍙備笌鑰呯殑 閿佸畾涓庢帶鍒秝riter鍙備笌鑰呯殑閿佸畾鍒嗗紑錛屽姞鍏eadWriteLock鍙備笌鑰咃紝浠ユ彁渚涗袱縐嶄笉鍚岀殑閿佸畾銆?br />
public final class ReadWriteLock {
private int readingReaders = 0; // (A)...瀹為檯姝ｅ湪璇誨彇鐨勬墽琛岀華鏁伴噺
private int waitingWriters = 0; // (B)...姝ｅ湪絳夊緟鍐欏叆鐨勬墽琛岀華鏁伴噺
private int writingWriters = 0; // (C)...瀹為檯姝ｅ湪鍐欏叆鐨勬墽琛岀華鏁伴噺
private boolean preferWriter = true; // 鍐欏叆浼樺厛鐨勮瘽錛屽€間負true
public synchronized void readLock() throws InterruptedException {
while (writingWriters > 0 || (preferWriter && waitingWriters > 0)) {
wait();
}
readingReaders++; // (A)瀹為檯姝ｅ湪璇誨彇鐨勭嚎紼嬫暟閲忓姞1
}
public synchronized void readUnlock() {
readingReaders--; // (A)瀹為檯姝ｅ湪璇誨彇鐨勭嚎紼嬫暟閲忓噺1
preferWriter = true;
notifyAll();
}
public synchronized void writeLock() throws InterruptedException {
waitingWriters++; // (B)姝ｅ湪絳夊緟鍐欏叆鐨勭嚎紼嬫暟閲忓姞1
try {
while (readingReaders > 0 || writingWriters > 0) {
wait();
}
} finally {1
waitingWriters--; // (B)姝ｅ湪絳夊緟鍐欏叆鐨勭嚎紼嬫暟閲忓噺1
}
writingWriters++; // (C)瀹為檯姝ｅ湪鍐欏叆鐨勭嚎紼嬫暟閲忓姞1
}
public synchronized void writeUnlock() {
writingWriters--; // (C)瀹為檯姝ｅ湪鍐欏叆鐨勭嚎紼嬫暟閲忓噺
preferWriter = false;
notifyAll();
}
}
public class Data {
private final char[] buffer;
private final ReadWriteLock lock = new ReadWriteLock();
public Data(int size) {
this.buffer = new char[size];
for (int i = 0; i < buffer.length; i++) {
buffer[i] = '*';
}
}
public char[] read() throws InterruptedException {
lock.readLock();
try {
return doRead();
} finally {
lock.readUnlock();
}
}
public void write(char c) throws InterruptedException {
lock.writeLock();
try {
doWrite(c);
} finally {
lock.writeUnlock();
}
}
private char[] doRead() {
char[] newbuf = new char[buffer.length];
for (int i = 0; i < buffer.length; i++) {
newbuf[i] = buffer[i];
}
slowly();
return newbuf;
}
private void doWrite(char c) {
for (int i = 0; i < buffer.length; i++) {
buffer[i] = c;
slowly();
}
}
private void slowly() {
try {
Thread.sleep(50);
} catch (InterruptedException e) {
}
}
}
7.Thread-Per-Message Pattern 鍦ㄦ柟娉曠殑灞炴€у鐞嗗畬鎴愪箣鍓嶏紝鎺у埗鏉冧笉浼氫粠Host鍙備笌鑰呴€€鍑恒€傚鏋滄柟娉曠殑澶勭悊
灞炴€у緢璇濊垂鏃墮棿錛岀▼搴忕殑鍝嶅簲鎬ц兘浼氶檷浣庛€傝В鍐崇殑鏂瑰紡灝卞湪Host鐨勫弬涓庤€呴噷錛屽惎鍔ㄦ柊鐨勭嚎紼嬶紝騫朵笖灝嗚鏂規硶搴?nbsp; 璇ヨ繘琛岀殑宸ヤ綔浜ょ粰榪欎釜蹇冪殑綰跨▼錛岃繖鏍稢lient鍙備笌鑰呯殑綰跨▼鍙互緇х畫鎵ц涓嬩竴涓搷浣滐紝榪欐牱鍋氾紝涓嶇敤鏇存敼 Client鍙備笌鑰呯殑紼嬪簭浠ｇ爜錛屽茍鑳芥彁楂樼▼搴忕殑鍝嶅簲鎬с€傛兂鑺傜渷鍚姩綰跨▼鎵€鑺辮垂鐨勬椂闂達紝鍙互浣跨敤Worker Thread Pattern銆?br /> public class Host {
private final Helper helper = new Helper();
public void request(final int count, final char c) {
System.out.println(" request(" + count + ", " + c + ") BEGIN");
new Thread() {
public void run() {
helper.handle(count, c);
}
}.start();
System.out.println(" request(" + count + ", " + c + ") END");
}
}
8.Worker Thread Pattern 濡傛灉鏂規硶鐨勫鐞嗗睘鎬у緢鑺辨椂闂達紝紼嬪簭鐨勫搷搴旀€т細闄嶄綆銆備負浜嗘彁渚涘搷搴旀€э紝鑰屽惎鍔ㄦ柊
鐨勭嚎紼嬫潵澶勭悊鏂規硶鏃訛紝鍚姩綰跨▼鎵€鑺辯殑鏃墮棿鍙堜細闄嶄綆throughput銆傚彟澶栧綋閫佸嚭鐨勮姹傚お澶氭椂錛屼細鍚姩
榪囧鐨勭嚎紼嬶紝榪欎細浣挎壙杞介噺鍙樺樊銆?br /> public class Channel {
private static final int MAX_REQUEST = 100;
private final Request[] requestQueue;
private int tail; // 顥活棪涓嬩竴涓猵utRequest鐨勫湴鏂?br /> private int head; // 顥活棪涓嬩竴涓猼akeRequest鐨勫湴鏂?br /> private int count; // Request鐨勬暟閲?br />
private final WorkerThread[] threadPool;
public Channel(int threads) {
this.requestQueue = new Request[MAX_REQUEST];
this.head = 0;
this.tail = 0;
this.count = 0;
threadPool = new WorkerThread[threads];
for (int i = 0; i < threadPool.length; i++) {
threadPool[i] = new WorkerThread("Worker-" + i, this);
}
}
public void startWorkers() {
for (int i = 0; i < threadPool.length; i++) {
threadPool[i].start();
}
}
public synchronized void putRequest(Request request) {
while (count >= requestQueue.length) {
try {
wait();
} catch (InterruptedException e) {
}
}
requestQueue[tail] = request;
tail = (tail + 1) % requestQueue.length;
count++;
notifyAll();
}
public synchronized Request takeRequest() {
while (count <= 0) {
try {
wait();
} catch (InterruptedException e) {
}
}
Request request = requestQueue[head];
head = (head + 1) % requestQueue.length;
count--;
notifyAll();
return request;
}
}
9.Future Pattern 褰揅lient浼氬皢宸ヤ綔濮旀墭緇欏叾浠栫嚎紼嬶紝鑰孋lient鍙備笌鑰呭笇鏈涘緱鍒板鐞嗙殑緇撴灉銆傚皢宸ヤ綔濮旀墭緇?br /> 鍒漢鏃訛紝濡傛灉鍙堢瓑寰呮墽琛岀粨鏋滐紝浼氫嬌鍝嶅簲鎬ч檷浣庛€?br /> public class FutureData implements Data {
private RealData realdata = null;
private boolean ready = false;
public synchronized void setRealData(RealData realdata) {
if (ready) {
return; // balk
}
this.realdata = realdata;
this.ready = true;
notifyAll();
}
public synchronized String getContent() {
while (!ready) {
try {
wait();
} catch (InterruptedException e) {
}
}
return realdata.getContent();
}
}
闄勫綰跨▼紼嬪簭鐨勮瘎浠鋒爣鍑?br /> 1銆佸畨鍏ㄦ€р€斺€斾笉鎹熷潖瀵硅薄 瀵硅薄鎹熷潖鏄寚瀵硅薄鐨勭姸鎬佷笉絎﹀悎璁捐甯堢殑鍘熸剰錛岄€氬父鏄幏鍙栧璞＄殑鐘舵€佸€煎茍闈為鏈熷€箋€?br /> 2銆佺敓瀛樻€р€斺€旇繘琛屽繀瑕佺殑澶勭悊 涔熻涓嶆槸鐜板湪錛屼絾鏄竴瀹氫細榪涜蹇呰鐨勫鐞嗭紝濡傛灉紼嬪簭瀹夊叏浜嗭紝浣嗘槸鏈変簺蹇呰鐨勫鐞嗗緱涓嶅埌鎿嶄綔錛岄偅涔堣繖涓綰跨▼紼嬪簭涔熸槸涓嶅悎鏍肩殑銆?br /> 3銆佸鐢ㄦ€р€斺€斿彲鍐嶅埄鐢ㄧ被 鍐欏綰跨▼紼嬪簭錛屽鏋滆兘澶熷皢澶氱嚎紼嬬殑鍏變韓鍜屼簰鏂ョ粨鏋勯殣钘忓湪綾婚噷闈紝榪欏氨鏄竴涓珮搴﹀彲澶嶅嵃鐨勭▼搴忋€?br /> 4銆佹€ц兘鈥斺€旇兘蹇€熷ぇ閲忓鐞?涓昏琛ㄧ幇鍦ㄥ悶鍚愰噺錛圱hroughput錛夊嵆涓€瀹氭椂闂村唴鑳藉畬鎴愮殑澶勭悊閲忥紝鑳藉畬鎴愮殑澶勭悊閲忚秺澶氾紝琛ㄧず鏁版嵁鍚炲悙閲忚秺澶э紱瀹歸噺錛圕apacity錛夋寚鍙悓鏃跺鐞嗙殑鏁伴噺錛涘搷搴旀€э紙Responsiveness錛夋寚浠庡彂鍑鴻姹傚埌鏀跺埌鍝嶅簲鐨勬椂闂達紝鏃墮棿瓚婄煭錛屽搷搴旀€ц秺楂樸€?br /> 5銆佷幾緙╂€э紙Scalability錛夌瓑
鍓嶄袱涓槸蹇呰鏉′歡錛屽悗闈㈠嚑涓槸紼嬪簭璐ㄩ噺鐨勬弿榪?br />
]]>
浠ヤ笂閫昏緫綆€鍗曠殑璇村氨鏄細濡傛灉鏉′歡涓嶆弧瓚籌紝鍒欑瓑寰呫€?br /> 褰撴潯浠舵弧瓚蟲椂錛岀瓑寰呰鏉′歡鐨勭嚎紼嬪皢琚敜閱掋€?br /> 鍦↗ava涓紝榪欎釜鏈哄埗鐨勫疄鐜頒緷璧栦簬wait/notify銆傜瓑寰呮満鍒跺拰閿佹満鍒舵槸瀵嗗垏鍏寵仈鐨勩€?br /> 渚嬪錛氥€€銆€
1 synchronized(obj)
2 {銆€銆€
3 while(!condition)
4 {
5 銆€銆€obj.wait();銆€銆€
6
7 }銆€銆€
8 obj.doSomething();銆€銆€
9 }銆€
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2 {銆€銆€
3 while(!condition)
4 {
5 銆€銆€obj.wait();銆€銆€
6
7 }銆€銆€
8 obj.doSomething();銆€銆€
9 }銆€
1 synchronized(obj)
2 {銆€銆€
3 condition = true;銆€銆€
4 obj.notify();銆€銆€
5 }銆€
2 {銆€銆€
3 condition = true;銆€銆€
4 obj.notify();銆€銆€
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# 褰搊bj.wait()鏂規硶榪斿洖鍚庯紝綰跨▼A闇€瑕佸啀嬈¤幏寰梠bj閿侊紝鎵嶈兘緇х畫鎵ц銆傘€€銆€
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# obj.notifyAll()鍒欒兘鍏ㄩ儴鍞ら啋A1,A2,A3錛屼笉榪囪緇х畫鎵цobj.wait()鐨勪笅涓€鏉¤鍙ワ紝蹇呴』鑾峰緱obj閿侊紝鍥犳錛孉1,A2,A3鍙湁涓€涓湁鏈轟細鑾峰緱閿佺戶緇墽琛岋紝渚嬪A1錛屽叾浣欑殑闇€瑕佺瓑寰匒1閲婃斁obj閿佷箣鍚庢墠鑳界戶緇墽琛屻€傘€€銆€
# 褰揃璋冪敤obj.notify/notifyAll鐨勬椂鍊欙紝B姝ｆ寔鏈塷bj閿侊紝鍥犳錛孉1,A2,A3铏借鍞ら啋錛屼笉榪囦粛鏃犳硶鑾峰緱obj閿併€傜洿鍒癇閫€鍑簊ynchronized鍧楋紝閲婃斁obj閿佸悗錛孉1,A2,A3涓殑涓€涓墠鏈夋満浼氳幏寰楅攣緇х畫鎵ц銆?
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