馃懆鈥嶐煉诲崥瀹富椤碉細浣滆€呬富椤叼煈嶈寰楁枃绔犱笉閿欑殑鏈嬪弸鍙互鐐硅禐鍏虫敞馃巵绮変笣绂忓埄锛氭墍鏈夊涔犺祫鏂欏拰绠€鍘嗘ā鏉块兘鍙互鐐瑰嚮鏀惰棌浠€涔堟槸ThreadLocalThreadLocal鍙堝彨浠€涔坱hreadlocalVariable锛屽叏绉皌hreadlocalvariable锛屼富瑕佺敤浜庤В鍐冲绾跨▼涓暟鎹苟鍙戝鑷寸殑涓嶄竴鑷撮棶棰樸€俆hreadLocal涓烘瘡涓嚎绋嬮兘鎻愪緵浜嗕竴浠藉彉閲忕殑鍓湰锛屼娇寰楁瘡涓嚎绋嬪湪鏌愪釜鏃跺埢閮戒笉浼氳闂悓涓€涓璞★紝闅旂浜嗗涓嚎绋嬪鏁版嵁鐨勫叡浜紝鍏剁粨鏋滄棤闈炲氨鏄秷鑰楀唴瀛橈紝涔熷ぇ澶у噺灏戜簡绾跨▼鍚屾甯︽潵鐨勬€ц兘娑堣€楋紝涔熼檷浣庝簡绾跨▼骞跺彂鎺у埗鐨勫鏉傚害銆傛€荤殑鏉ヨ锛歍hreadLocal閫傜敤浜庢瘡涓嚎绋嬮兘闇€瑕佽嚜宸辩嫭绔嬬殑瀹炰緥锛屽苟涓旇瀹炰緥闇€瑕佸湪澶氫釜鏂规硶涓娇鐢紝鍗冲彉閲忓湪绾跨▼涔嬮棿鏄殧绂荤殑锛屼絾鍦ㄦ柟娉曟垨绫讳腑鏄叡浜殑ThreadLocal鍜孲ynchronized鏈変粈涔堝尯鍒紵ThreadLocal鍜孲ynchonized铏界劧閮芥槸鐢ㄦ潵瑙ｅ喅澶氱嚎绋嬪苟鍙戣闂殑锛屼絾鏄畠浠箣闂磋繕鏄湁涓€浜涙湰璐ㄧ殑鍖哄埆锛歋ynchronized浣跨敤浜嗛攣鏈哄埗锛屼娇寰楀彉閲忔垨鑰呬唬鐮佸潡鍦ㄥ悓涓€鏃堕棿鍙兘琚竴涓汉璁块棶銆傜嚎绋嬫潵璁块棶銆俆hreadLocal涓烘瘡涓嚎绋嬫彁渚涗簡涓€浠藉彉閲忕殑鍓湰锛屼娇寰楁瘡涓嚎绋嬪湪鏌愪釜鏃跺埢璁块棶鐨勫璞′笉浼氭槸鍚屼竴涓璞★紝闅旂浜嗗涓嚎绋嬪鏁版嵁鐨勫叡浜€傚悓姝ュ寲姝ｅソ鐩稿弽銆傚彲鐢ㄤ簬澶氱嚎绋嬮棿鐨勯€氫俊锛岃幏鍙栨暟鎹叡浜€傛敞鎰忥細ThreadLocal涓嶈兘浣跨敤鍘熷瓙绫诲瀷锛屽彧鑳界畝鍗曚娇鐢∣bject绫诲瀷ThreadLocalpublicclassThreadLocaTest{privatestaticThreadLocallocal=newThreadLocal();staticvoidprint(Stringstr){//鎵撳嵃褰撳墠绾跨▼鏈湴鍐呭瓨涓彉閲忕殑鍊糞ystem.out.println(str+":"+local.get());//娓呴櫎鍐呭瓨涓殑灞€閮ㄥ彉閲弆ocalVar.remove();}publicstaticvoidmain(String[]args)throwsInterruptedException{newThread(newRunnable(){publicvoidrun(){ThreadLocaTest.local.set("xdclass_A");print("A");//鎵撳嵃鏈湴鍙橀噺System.out.println("clearAfter:"+local.get());}},"A").start();绾跨▼.鐫＄湢(1000);newThread(newRunnable(){publicvoidrun(){ThreadLocaTest.local.set("xdclass_B");print("B");System.out.println("娓呴櫎鍚?+localVar.get());}},"B").start();}}杩愯鍚庡彲浠ョ湅鍒皒dclass_A鐨勫€间负null锛寈dclass_B鐨勫€间篃涓簄ull锛岃鏄庝袱涓嚎绋嬮兘鑾峰彇浜嗚嚜宸辩嚎绋嬩腑瀛樺偍鐨勫彉閲忥紝瀹冧滑涔嬮棿鑾峰彇鐨勫彉閲忎笉浼氭贩娣嗐€俆hreadLocal鏍稿績搴旂敤鍦烘櫙浠嬬粛ThreaLocal浣滅敤浜庢瘡涓嚎绋嬮兘闇€瑕佺嫭绔嬩繚瀛樹俊鎭紝鏂逛究鍚岀嚎绋嬬殑鍏朵粬鏂规硶鑾峰彇淇℃伅銆傜敱浜庢瘡涓嚎绋嬭幏鍙栧埌鐨勪俊鎭彲鑳戒笉鍚岋紝鍦ㄥ墠闈㈡墽琛岀殑鏂规硶淇濆瓨淇℃伅鍚庯紝鍚庨潰鐨勬柟娉曞彲浠ョ洿鎺ラ€氳繃ThreadLocal鑾峰彇锛岄伩鍏嶄簡鍙傛暟浼犻€掞紝绫讳技浜庡叏灞€鍙橀噺鐨勬蹇点€備緥濡備粠鐢ㄦ埛绯荤粺鑾峰彇鐨勭敤鎴风櫥褰晅oken銆佺敤鎴锋潈闄愪俊鎭€佺敤鎴峰悕瑙ｅ瘑鍚庣殑淇℃伅浼犻€掑涓婂浘鎵€绀恒€傛瘮濡傜嚎绋婣鐨勬柟娉?鍒涘缓浜嗗彉閲廇锛屾柟娉?鍜屾柟娉?涓€鏍凤紝鍦ㄥ悓涓€涓嚎绋嬩腑锛屽垱寤虹殑鍙橀噺A鏄叡浜殑銆?鐢ㄦ埛寰湇鍔￠厤缃护鐗岃В瀵嗕俊鎭紶閫掔ず渚媝ublicstaticThreadLocalthreadLocal=newThreadLocal<>();鐧诲綍鐢ㄦ埛loginUser=newLoginUser();鐧诲綍鐢ㄦ埛.setId(id);loginUser.setName(鍚嶇О);loginUser.setMail锛堥偖浠讹級锛沴oginUser.setHeadImg(headImg);threadLocal.set锛堢櫥褰曠敤鎴凤級锛涘鏋滃悗闈㈡兂鐩存帴鑾峰彇threadLocal.getxxx锛屽彲浠ヤ娇鐢═hreadLocal鏉ヨВ鍐崇嚎绋嬪畨鍏ㄩ棶棰樸€傚湪鎴戜滑骞虫椂鐨凷pringWeb椤圭洰涓紝鎴戜滑閫氬父浼氫娇鐢ㄥ皢涓氬姟鍒嗕负Controller銆丼ervice銆丏ao绛夛紝涔熺煡閬撴敞瑙Autowired榛樿浣跨敤鐨勬槸鍗曚緥妯″紡銆備綘鏈夋病鏈夋兂杩囧綋涓嶅悓鐨勮姹傜嚎绋嬭繘鏉ョ殑鏃跺€欙紝鍥犱负Dao灞備娇鐢ㄤ簡鍗曚緥锛屾墍浠ュ彧鏈変竴涓狢onnection璐熻矗杩炴帴鏁版嵁搴撱€傝繖鏃跺€欙紝濡傛灉鎵€鏈夌殑璇锋眰绾跨▼閮借繛鎺ュ埌鏁版嵁搴擄紝杩欏氨浼氶€犳垚杩欎釜Spring濡備綍瑙ｅ喅绾跨▼涓嶅畨鍏ㄧ殑闂鍛紵Dao灞傜粍瑁呯殑Connection绾跨▼鑲畾鏄畨鍏ㄧ殑锛岃В鍐虫柟娉曞氨鏄娇鐢═hreadLocal鏂规硶銆傛瘡涓姹傜嚎绋嬩娇鐢–onnection鏃讹紝閮戒細浠嶵hreadLocal涓幏鍙栦竴娆°€傚鏋滃€间负null锛屽垯琛ㄧず娌℃湁杩炴帴鍒版暟鎹簱锛岃繛鎺ュ悗浼氬瓨鍌ㄥ湪ThreadLocal涓€傝繖鏍锋瘡涓嚎绋嬮兘淇濆瓨涓€浠藉睘浜庤嚜宸辩殑Connection銆傛瘡涓嚎绋嬬淮鎶よ嚜宸辩殑鏁版嵁锛岃揪鍒扮嚎绋嬬殑闅旂鏁堟灉銆傛厧鐢═hreadLocal鐨勫満鏅涓€鐐癸紙绾跨▼姹犱腑鐨勭嚎绋嬭皟鐢═hreadLocal锛夛細鐢变簬绾跨▼姹犱腑绾跨▼鐨勭鐞嗘槸涓€绉嶇嚎绋嬪鐢ㄧ殑鏂瑰紡锛岀嚎绋嬪緢闅惧湪绾跨▼姹犱腑缁撴潫锛屽苟涓斾粬浠洿鏈夊彲鑳芥案杩滀笉浼氱粨鏉熴€備細鍋溿€傝繖鎰忓懗鐫€绾跨▼鐨勬寔缁椂闂存槸涓嶅彲棰勬祴鐨勶紝鐢氳嚦涓嶫VM鐨勭敓鍛藉懆鏈熼噸鍚堛€傜浜岀偣锛堝湪寮傛绋嬪簭涓級锛歍hreadLocal浼犲弬鏄笉鍙潬鐨勶紝鍥犱负绾跨▼鍙戦€佽姹傚悗锛屼笉浼氫竴鐩村線涓嬭窇锛岀瓑寰呰繙绋嬭繑鍥炵粨鏋溿€傚緱鍒扮湡姝ｇ殑杩斿洖缁撴灉鍚庯紝鍙兘鏄叾浠栫嚎绋嬪湪澶勭悊銆傜涓夌偣锛氫娇鐢═hreadLocal鍚庯紝寤鸿璋冪敤remove()鏂规硶锛岃繖鏍峰彲浠ラ槻姝㈠唴瀛樻孩鍑虹殑鍙戠敓锛屽洜涓篢hreadLocal鏄急寮曠敤銆俆hreadLocal濡傛灉涓嶆槸琚閮ㄥ己寮曠敤锛屽瀮鍦惧洖鏀舵椂浼氳娓呯悊鎺夛紝濡傛灉鏄己寮曠敤鍒欎笉浼氳娓呯悊鎺夈€傝交鏉炬帉鎻hreadLocal鐨勫簳灞傛簮鐮佽В璇?鍘熺悊ThreadLocal鐨剆et鏂规硶锛岄鍏圱hreadt=Thread.currentThread琛ㄧず鑾峰彇褰撳墠绾跨▼锛岀劧鍚庤幏鍙栫嚎绋嬩腑鐨勫睘鎬hreadLocalMap锛岀劧鍚庡垽鏂璗hreadLocalMap锛屽鏋滀笉鏄紝濡傛灉鏄负绌猴紝鐩存帴鏇存柊瑕佷繚瀛樼殑鍙橀噺鍊硷紝鍚﹀垯鍒涘缓涓€涓猼hreadLocalMap骞惰祴鍊笺€傞偅涔圱hreadLocalMap鏂规硶鏈変粈涔堜綔鐢ㄥ憿锛熸帴涓嬫潵锛屾垜浠竴璧锋潵鐪嬬湅鍚с€傛垜浠彲浠ョ湅鍒癟hreadLocalMap鏄疶hreadLocal鐨勪竴涓唴閮ㄩ潤鎬佺被銆傝繖涓被鐨勭粍鎴愪富瑕佹槸鐢‥ntry鏉ュ瓨鍌ㄦ暟鎹紝涔熸槸涓€涓户鎵跨殑寮卞紩鐢ㄣ€俆hreadLocal浣滀负Entry鍐呴儴鐨刱ey锛屾垜浠嚜宸辫缃殑value浼氫綔涓鸿繖閲岀殑value銆備笂闈㈠凡缁忔彁鍒颁簡set鍜孴hreadLocalMap鏂规硶銆傛帴涓嬫潵鎴戜滑鐪嬩竴涓媑et鏂规硶銆傚彲浠ョ湅鍑篻et鏂规硶鍜宻et鏂规硶闈炲父鐩镐技銆備篃鏄厛鑾峰彇褰撳墠绾跨▼锛屽啀鑾峰彇绾跨▼鐨凾hreadLocalMap锛屽啀鍒ゆ柇map銆傚鏋滃湴鍥剧殑鏁版嵁涓虹┖锛屽垯鑾峰彇瀛樺偍鐨勫€笺€傚鏋滄暟鎹负null锛屽垯寮€濮嬪垵濮嬪寲锛屽垵濮嬪寲鐨勭粨鏋滄槸Theradlocalmap涓瓨鍌ㄧ殑鍊间负null銆傚彲浠ョ湅鍒板熀鏈笂鎵€鏈夌殑鎿嶄綔閮芥湁杩欎釜ThreadLocalMap銆傛绫讳笉瀹炵幇鍦板浘鎺ュ彛銆傚畠鍙槸涓€涓櫘閫氱殑java绫伙紝浣嗘槸瀹炵幇鐨勭被绫讳技浜巑ap鐨勫姛鑳姐€傛暟鎹瓨鍌ㄥ湪Entry涓紝瀹冪户鎵胯嚜WeakReference锛屼娇鐢↘ey-value瀵瑰瓨鍌紝key鏄ThreadLocal鐨勫紩鐢ㄣ€傛瘡涓嚎绋嬮兘鏈変竴涓猅hreadLocalMap瀵硅薄锛屾瘡涓€涓柊鐨勭嚎绋婽hread閮戒細瀹炰緥鍖栦竴涓猅hreadLocalMap骞剁粰鎴愬憳鍙橀噺threadLocals璧嬪€笺€傘€愰潰璇曢銆戜负浠€涔圱hreadLocal鐨刱ey鏄急寮曠敤锛屽鏋滄槸寮哄紩鐢ㄤ細鎬庢牱锛熶粈涔堟槸寮卞紩鐢紵锛堝垵瀛﹁€呰璺宠繃~锛夊湪java涓紝闄や簡鍩烘湰鏁版嵁绫诲瀷锛屽叾浠栭兘鏄紩鐢ㄧ被鍨嬶紝java灏嗗紩鐢ㄧ被鍨嬪垎涓哄己寮曠敤銆佽蒋寮曠敤銆佸急寮曠敤鍜屽够寮曠敤銆備竴鑸儏鍐典笅锛屾垜浠€氬父鍙敵璇峰己寮曠敤绫诲瀷锛屽叾浠栧紩鐢ㄧ被鍨嬪彧鑳藉湪闈㈣瘯鎴栬€呴槄璇绘簮鐮佺殑鏃跺€欐墠鑳界湅鍒般€傚己寮曠敤锛歯ew杩欐牱鐨勫璞℃槸瀵筄bjectobj=newObject()鐨勫己寮曠敤銆傚鏋滆蒋寮曠敤鐨勭敓鍛藉懆鏈熸瘮寮哄紩鐢ㄧ煭锛屽垯閫氳繃SoftReference绫绘潵瀹炵幇銆傚綋鍐呭瓨涓湁瓒冲鐨勭┖闂存椂锛屽瀮鍦炬敹闆嗗櫒灏嗕笉浼氬鍏惰繘琛屽洖鏀讹紱鍥犱负褰揓VM璁や负鍐呭瓨绌洪棿涓嶈冻鏃讹紝浼氬皾璇曞洖鏀惰蒋寮曠敤鎸囧畾鐨勫璞★紝涔熷氨鏄JVM浼氬湪鎶涘嚭OutOfMemoryError寮傚父鍓嶆竻鐞嗘帀杞紩鐢ㄥ璞°€傝蒋寮曠敤鐨勪娇鐢ㄥ満鏅細姣旇緝閫傚悎瀹炵幇缂撳瓨銆傚綋鍐呭瓨绌洪棿瓒冲鏃讹紝灏嗙紦瀛樺瓨鏀惧湪鍐呭瓨涓€傚鏋滃唴瀛樹笉瓒筹紝鍙互鍥炴敹缂撳瓨銆傚急寮曠敤锛氬急寮曠敤鏄€氳繃WeakReference绫诲疄鐜扮殑銆傚畠鐨勭敓鍛藉懆鏈熸瘮杞紩鐢ㄧ煭锛堜竴涓瘮涓€涓煭锛夈€傚湪鍨冨溇鍥炴敹鏃讹紝涓嶇鍐呭瓨绌洪棿鏄惁瓒冲锛岃繖涓璞￠兘浼氳鍥炴敹銆傚彲浠ラ殢鏃惰幏鍙栵紝浣嗗張涓嶆兂褰卞搷瀵硅薄鐨勫瀮鍦惧洖鏀躲€傝繖鏃跺€欏彲浠ヨ€冭檻浣跨敤寮卞紩鐢ㄦ潵鎸囧悜杩欎釜瀵硅薄銆傝浜嗚繖涔堝锛岃繕鏄病鏈夎鍒拌繖涓潰璇曢銆傜幇鍦ㄨ鎴戜滑璋堣皥濡備綍鍥炵瓟杩欎釜闈㈣瘯闂銆備负浠€涔圱hreadLocal鏄急寮曠敤锛熺涓€锛屽鏋滄槸寮哄紩鐢紝鍗充娇ThreadLocal鐨勫€间负null锛孴hreadLocalMap浠嶇劧浼氭湁ThreadLocal鐨勫己寮曠敤鐘舵€併€傚鏋滀笉鎵嬪姩鍒犻櫎锛孴hreadLocal涓嶄細琚洖鏀讹紝浼氬鑷村叆鍙ｅ唴瀛樸€傚叾娆★紝濡傛灉鏄急寮曠敤锛屽垯鍥炴敹寮曠敤ThreadLocal鐨勫璞★紝ThreadLocalMap浠嶇劧淇濈暀瀵筎hreadLocal鐨勫急寮曠敤銆傚嵆浣夸笉鎵嬪姩鍒犻櫎锛孴hreadLocal涔熶細琚洖鏀躲€備笅娆hreadLocalMap璋冪敤set/get/remove鏂规硶鏃讹紝璇ュ€煎皢琚竻闄ゃ€?/p>
