Java 八鏃犱汉璋堝強鐨勫叓澶у姛鑳

鏃堕棿鎴抽攣

涓€鐩翠互鏉ワ紝澶氱嚎绋嬩唬鐮佹槸鏈嶅姟鍣ㄥ紑鍙戜汉鍛樼殑姣掕嵂锛堥棶闂甇racle鐨凧ava璇█鏋舵瀯甯堝拰骞惰寮€鍙戝ぇ甯圔rian Goetz锛夈€侸ava鐨勬牳蹇冨簱涓嶆柇鍔犲叆鍚勭澶嶆潅鐨勭敤娉曟潵鍑忓皯璁块棶鍏变韩璧勬簮鏃剁殑绾跨▼绛夊緟鏃堕棿銆傚叾涓箣涓€灏辨槸缁忓吀鐨勮鍐欓攣锛圧eadWriteLock锛夛紝 瀹冭浣犳妸浠ｇ爜鍒嗘垚涓ら儴鍒嗭細闇€瑕佷簰鏂ョ殑鍐欐搷浣滃拰涓嶉渶瑕佷簰鏂ョ殑璇绘搷浣溿€?/p>

琛ㄩ潰涓婄湅璧锋潵寰堜笉閿欍€傞棶棰樻槸璇诲啓閿佹湁鍙兘鏄瀬鎱㈢殑锛堟渶澶?0鍊嶏級锛岃繖宸茬粡鍜屽畠鐨勫垵琛风浉鎮栦簡銆侸ava 8寮曞叆浜嗕竴绉嶆柊鐨勮鍐欓攣鈥斺€斿彨鍋氭椂闂存埑閿併€傚ソ娑堟伅鏄繖涓浼欑湡鐨勯潪甯稿揩銆傚潖娑堟伅鏄畠浣跨敤璧锋潵鏇村鏉傦紝鏈夋洿澶氱殑鐘舵€侀渶瑕佸鐞嗐€傚苟涓斿畠鏄笉鍙噸鍏ョ殑锛岃繖鎰忓懗鐫€ 涓€涓嚎绋嬫湁鍙兘璺熻嚜宸辨閿併€?/p>

鏃堕棿鎴抽攣鏈変竴绉嶁€滀箰瑙傗€濇ā寮忥紝鍦ㄨ繖绉嶆ā寮忎笅姣忔鍔犻攣鎿嶄綔閮戒細杩斿洖涓€涓椂闂存埑浣滀负鏌愮鏉冮檺鍑瘉锛涙瘡娆¤В閿佹搷浣滈兘闇€瑕佹彁渚涘畠瀵瑰簲鐨勬椂闂存埑銆傚鏋滀竴涓嚎绋?鍦ㄨ姹備竴涓啓鎿嶄綔閿佺殑鏃跺€欙紝杩欎釜閿佺宸у凡缁忚涓€涓鎿嶄綔鎸佹湁锛岄偅涔堣繖涓鎿嶄綔鐨勮В閿佸皢浼氬け鏁堬紙鍥犱负鏃堕棿鎴冲凡缁忓け鏁堬級銆傝繖涓椂鍊欏簲鐢ㄧ▼搴忛渶瑕佷粠澶村啀鏉ワ紝涔熻 瑕佷娇鐢ㄦ偛瑙傛ā寮忕殑閿侊紙鏃堕棿鎴抽攣涔熸湁瀹炵幇锛夈€備綘闇€瑕佽嚜宸辨悶瀹氳繖涓€鍒囷紝骞朵笖涓€涓椂闂存埑鍙兘瑙ｉ攣瀹冨搴旂殑閿佲€斺€旇繖涓€鐐瑰繀椤婚潪甯稿皬蹇冦€?/p>

涓嬮潰鎴戜滑鏉ョ湅涓€涓嬭繖绉嶉攣鐨勫疄渚嬧€斺€?/p>

long stamp = lock.tryOptimisticRead(); // 闈為樆濉炶矾寰勨€斺€旇秴绾у揩
work(); // 鎴戜滑甯屾湜涓嶈鏈夊啓鎿嶄綔鍦ㄨ繖鏃跺彂鐢?
if (lock.validate(stamp)){
       //鎴愬姛锛佹病鏈夊啓鎿嶄綔骞叉壈 
}
else {
       //鑲畾鍚屾椂鏈夊彟澶栦竴涓嚎绋嬭幏寰椾簡鍐欐搷浣滈攣锛屾敼鍙樹簡鏃堕棿鎴?
       //鎳掓眽璇粹€斺€旀垜浠垏鎹㈠埌寮€閿€鏇村ぇ鐨勯攣鍚?
	
            stamp = lock.readLock(); //杩欐槸浼犵粺鐨勮鎿嶄綔閿侊紝浼氶樆濉?
       try {
                 //鐜板湪涓嶅彲鑳芥湁鍐欐搷浣滃彂鐢熶簡
                 work();

       }
       finally {
            lock.unlock(stamp); // 浣跨敤瀵瑰簲鐨勬椂闂存埑瑙ｉ攣
       }
}

骞跺彂鍔犳硶鍣?

Java 8鍙︿竴涓嚭鑹茬殑鍔熻兘鏄苟鍙戔€滃姞娉曞櫒鈥濓紝瀹冨澶ц妯¤繍琛岀殑浠ｇ爜灏ゅ叾鏈夋剰涔夈€備竴绉嶆渶鍩烘湰鐨勫苟鍙戞ā寮忓氨鏄涓€涓鏁板櫒鐨勮鍐欍€傚氨鍏舵湰韬€岃█锛岀幇浠婂鐞嗚繖涓棶棰樻湁寰堝鏂规硶锛屼絾鏄病鏈変竴绉嶈兘姣擩ava 8鎻愪緵鐨勬柟娉曢珮鏁堟垨浼橀泤銆?/p>

鍒扮洰鍓嶄负姝紝杩欎釜闂鏄敤鍘熷瓙绫伙紙Atomics锛夋潵瑙ｅ喅鐨勶紝瀹冪洿鎺ュ埄鐢ㄤ簡CPU鐨勨€滄瘮杈冨苟浜ゆ崲鈥濇寚浠わ紙CAS锛夋潵娴嬭瘯骞惰缃鏁板櫒鐨勫€笺€傞棶棰樺湪浜?褰撲竴鏉AS鎸囦护鍥犱负绔炰簤鑰屽け璐ョ殑鏃跺€欙紝AtomicInteger绫讳細姝荤瓑锛屽湪鏃犻檺寰幆涓笉鏂皾璇旵AS鎸囦护锛岀洿鍒版垚鍔熶负姝€傚湪鍙戠敓绔炰簤姒傜巼寰堥珮鐨勭幆澧?涓紝杩欑瀹炵幇琚瘉鏄庢槸闈炲父鎱㈢殑銆?/p>

鏉ョ湅Java 8鐨凩ongAdder銆傝繖涓€绯诲垪绫讳负澶ч噺骞惰璇诲啓鏁板€肩殑浠ｇ爜鎻愪緵浜嗘柟渚跨殑瑙ｅ喅鍔炴硶銆備娇鐢ㄨ秴绾х畝鍗曘€傚彧瑕佸垵濮嬪寲涓€涓狶ongAdder瀵硅薄骞朵娇鐢ㄥ畠鐨刟dd()鍜宨ntValue()鏂规硶鏉ョ疮鍔犲拰閲囨牱璁℃暟鍣ㄣ€?/p>

杩欏拰鏃х殑Atomic绫荤殑鍖哄埆鍦ㄤ簬锛屽綋CAS鎸囦护鍥犱负绔炰簤鑰屽け璐ユ椂锛孉dder涓嶄細涓€鐩村崰鐫€CPU锛岃€屾槸涓哄綋鍓嶇嚎绋嬪垎閰嶄竴涓唴閮╟ell瀵硅薄鏉ュ瓨鍌?璁℃暟鍣ㄧ殑澧為噺銆傜劧鍚庤繖涓€煎拰鍏朵粬寰呭鐞嗙殑cell瀵硅薄涓€璧疯鍔犲埌intValue()鐨勭粨鏋滀笂銆傝繖鍑忓皯浜嗗弽澶嶄娇鐢–AS鎸囦护鎴栭樆濉炲叾浠栫嚎绋嬬殑鍙兘鎬с€?/p>

濡傛灉浣犻棶浣犺嚜宸憋紝浠€涔堟椂鍊欏簲璇ョ敤骞跺彂鍔犳硶鍣ㄨ€屼笉鏄師瀛愮被鏉ョ鐞嗚鏁板櫒锛熺畝鍗曠殑绛旀灏辨槸鈥斺€斾竴鐩磋繖涔堝仛銆?/p>

骞惰鎺掑簭

姝ｅ儚骞跺彂鍔犳硶鍣ㄨ兘鍔犻€熻鏁颁竴鏍凤紝Java 8杩樺疄鐜颁簡涓€绉嶇畝娲佺殑鏂规硶鏉ュ姞閫熸帓搴忋€傝繖涓璇€寰堢畝鍗曘€備綘涓嶅啀杩欎箞鍋氾細

Array.sort(myArray);

鑰屾槸杩欎箞鍋氾細

Arrays.parallelSort(myArray);

杩欎細鑷姩鎶婄洰鏍囨暟缁勫垎鍓叉垚鍑犱釜閮ㄥ垎锛岃繖浜涢儴鍒嗕細琚斁鍒扮嫭绔嬬殑CPU鏍镐笂鍘昏繍琛岋紝鍐嶆妸缁撴灉鍚堝苟璧锋潵銆傝繖閲屽敮涓€闇€瑕佹敞鎰忕殑鏄紝鍦ㄤ竴涓ぇ閲忎娇鐢ㄥ绾跨▼鐨勭幆澧冧腑锛屾瘮濡備竴涓箒蹇欑殑Web瀹瑰櫒锛岃繖绉嶆柟娉曠殑濂藉灏变細鍑忓急锛堥檷浣?0%浠ヤ笂锛夛紝鍥犱负瓒婃潵瓒婂鐨凜PU涓婁笅鏂囧垏鎹㈠鍔犱簡寮€閿€銆?/p>

鍒囨崲鍒版柊鐨勬棩鏈熸帴鍙?/h2>

Java 8寮曞叆浜嗗叏鏂扮殑date-time鎺ュ彛銆傚綋鍓嶆帴鍙ｇ殑澶у鏁版柟娉曢兘宸茶鏍囪涓篸eprecated锛屼綘灏辩煡閬撴槸鏃跺€欐帹鍑烘柊鎺ュ彛浜嗐€傛柊鐨勬棩鏈熸帴鍙ｄ负Java鏍?蹇冨簱甯︽潵浜嗘槗鐢ㄦ€у拰鍑嗙‘鎬э紝鑰屼互鍓嶅彧鑳界敤Joda time鎵嶈兘杈惧埌杩欐牱鐨勬晥鏋滐紙璇戣€呮敞锛欽oda time鏄竴涓涓夋柟鐨勬棩鏈熷簱锛屾瘮Java鑷甫鐨勫簱鏇村弸濂芥洿鏄撲簬绠＄悊锛夈€?/p>

璺熶换浣曟柊鎺ュ彛涓€鏍凤紝濂芥秷鎭槸鎺ュ彛鍙樺緱鏇翠紭闆呮洿寮哄ぇ銆備絾涓嶅垢鐨勬槸杩樻湁澶ч噺鐨勪唬鐮佸湪浣跨敤鏃ф帴鍙ｏ紝杩欎釜鐭椂闂村唴涓嶄細鏈夋敼鍙樸€?/p>

涓轰簡琛旀帴鏂版棫鎺ュ彛锛屽巻鍙叉偁涔呯殑Date绫绘柊澧炰簡toInstant()鏂规硶锛岀敤浜庢妸Date杞崲鎴愭柊鐨勮〃绀哄舰寮忋€傚綋浣犳棦瑕佷韩鍙楁柊鎺ュ彛甯︽潵鐨勫ソ澶勶紝鍙堣鍏奸【閭ｄ簺鍙帴鍙楁棫鐨勬棩鏈熻〃绀哄舰寮忕殑鎺ュ彛鏃讹紝杩欎釜鏂规硶浼氭樉寰楀挨鍏堕珮鏁堛€?/p>

鎺у埗鎿嶄綔绯荤粺杩涚▼

鎯冲湪浣犵殑浠ｇ爜閲屽惎鍔ㄤ竴涓搷浣滅郴缁熻繘绋嬶紝閫氳繃JNI璋冪敤灏辫兘瀹屾垚鈥斺€斾絾杩欎釜涓滆タ鎬讳护浜轰竴鐭ュ崐瑙ｏ紝浣犲緢鏈夊彲鑳藉緱鍒颁竴涓剰鎯充笉鍒扮殑缁撴灉锛屽苟涓斾竴璺即闅忕潃涓€浜涘緢绯熺硶鐨勫紓甯搞€?/p>

鍗充究濡傛锛岃繖鏄棤娉曢伩鍏嶇殑浜嬫儏銆備絾杩涚▼杩樻湁涓€涓鍘岀殑鐗规€у氨鏄€斺€斿畠浠悶涓嶅ソ灏变細鍙樻垚鍍靛案杩涚▼銆傜洰鍓嶄粠Java涓繍琛岃繘绋嬪甫鏉ョ殑闂鏄紝杩涚▼涓€鏃﹀惎鍔ㄥ氨寰堥毦鍘绘帶鍒跺畠銆?/p>

涓轰簡甯垜浠В鍐宠繖涓棶棰橈紝Java 8鍦≒rocess绫讳腑寮曞叆浜嗕笁涓柊鐨勬柟娉?/p>

1. destroyForcibly鈥斺€旂粨鏉熶竴涓繘绋嬶紝鎴愬姛鐜囨瘮浠ュ墠楂樺緢澶氥€?/li>
2. isAlive鈥斺€旀煡璇綘鍚姩鐨勮繘绋嬫槸鍚﹁繕娲荤潃銆?/li>
3. 閲嶈浇浜唚aitFor()锛屼綘鐜板湪鍙互鎸囧畾绛夊緟杩涚▼缁撴潫鐨勬椂闂翠簡銆傝繘绋嬫垚鍔熼€€鍑哄悗杩欎釜鎺ュ彛浼氳繑鍥烇紝瓒呮椂鐨勮瘽涔熶細杩斿洖锛屽洜涓轰綘鏈夊彲鑳借鎵嬪姩缁堟瀹冦€?/li>

杩欓噷鏈変袱涓叧浜庡浣曚娇鐢ㄨ繖浜涙柊鏂规硶鐨勫ソ渚嬪瓙鈥斺€?/p>

• 濡傛灉杩涚▼娌℃湁鍦ㄨ瀹氭椂闂村唴閫€鍑猴紝缁堟瀹冨苟缁х画寰€鍓嶈蛋銆?/li>

if (process.wait(MY_TIMEOUT, TimeUnit.MILLISECONDS)){
//鎴愬姛 }
else {
process.destroyForcibly();
}

• 鍦ㄤ綘鐨勪唬鐮佺粨鏉熷墠锛岀‘淇濇墍鏈夌殑杩涚▼閮藉凡閫€鍑恒€傚兊灏歌繘绋嬩細閫愭笎鑰楀敖绯荤粺璧勬簮銆?

for (Process p : processes) {
       if (p.isAlive()) {
             p.destroyForcibly();
       }
}

绮剧‘鐨勬暟瀛楄繍绠?/h2>

鏁板瓧婧㈠嚭浼氬鑷翠竴浜涜鍘岀殑bug锛屽洜涓哄畠鏈川涓婁笉浼氬嚭閿欍€傚湪涓€浜涚郴缁熶腑锛屾暣鍨嬪€间笉鍋滃湴澧為暱锛堟瘮濡傝鏁板櫒锛夛紝婧㈠嚭鐨勯棶棰樺氨灏や负涓ラ噸銆傚湪杩欎簺妗堜緥閲岄潰锛?浜у搧鍦ㄦ紨杩涢樁娈佃繍琛屽緱寰堝ソ锛岀敋鑷冲晢鐢ㄥ悗鐨勫緢闀挎椂闂村唴涔熸病闂锛屼絾鏈€缁堜細鍑哄鎬殑鏁呴殰锛屽洜涓鸿繍绠楀紑濮嬫孩鍑猴紝浜х敓浜嗗畬鍏ㄦ棤娉曢鏂欑殑鍊笺€?/p>

涓轰簡瑙ｅ喅杩欎釜闂锛孞ava 8涓篗ath绫绘坊鍔犱簡鍑犱釜鏂扮殑鈥滅簿纭瀷鈥濇柟娉曪紝浠ヤ究淇濇姢閲嶈鐨勪唬鐮佷笉鍙楁孩鍑虹殑褰卞搷锛屽畠鐨勫仛娉曟槸褰撹繍绠楄秴杩囧畠鐨勭簿搴﹁寖鍥寸殑鏃跺€欙紝鎶涘嚭涓€涓湭妫€鏌ョ殑ArithmeticException寮傚父銆?/p>

int safeC = Math.multiplyExact(bigA, bigB); 
// 濡傛灉缁撴灉瓒呭嚭+-2^31锛屽氨浼氭姏鍑篈rithmeticException寮傚父

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瀹夊叏鐨勯殢鏈烘暟鍙戠敓鍣?/h2>

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