锘??xml version="1.0" encoding="utf-8" standalone="yes"?>
銆銆1銆?/p>
QUESTION NO: 2
2,
鏍規(guī)嵁涓婇潰鐨勭▼搴?1錛屾垜浠湅鐪嬪緱鍒扮殑緇撴灉搴旇鏄粈涔堛?br />
榪欓亾棰樻秹鍙婄殑闂灝辨槸瀵硅薄涓庡璞′互鐢ㄧ殑闂錛岃繖涓棶棰樺ぇ瀹跺緢瀹規(guī)槗娣鋒穯銆傝繖閬撻鐨勭瓟妗堟槸1234銆?br />
閭d箞鏍規(guī)嵁闂1,浣犺兘鍚︾煡閬撻棶棰?鐨勭瓟妗堝憿,闂2鐨勭瓟妗堟槸2.
鍒嗘瀽錛氬瀵硅薄寮曠敤鐨勪笉鏄緢鐔熸?zhèn)夌殑錆h涓瀹氫互涓洪棶棰?鐨勭瓟妗堝簲璇ヤ笉鍙樹篃鏄?,鎬庝箞鏄?鍛?
榪欏氨鏄秹鍙婂璞′互鍙婂璞″紩鐢ㄧ殑闂浜?
涓棣栧厛浠嬬粛涓涓嬪璞$殑寮曠敤.
鍒涘緩瀵硅薄
鍒涘緩涓涓璞★紝鍏跺疄錛屽畠鍖呭惈浜嗗洓涓姩浣溿俹bject a=new object();
1錛夊彸杈圭殑“new object”錛屾槸浠bject綾諱負妯℃澘錛屽湪鍫嗙┖闂撮噷鍒涘緩涓涓猳bject綾誨璞★紙涔熺畝縐頒負object瀵硅薄錛夈?br />
2錛夋湯灝劇殑()鎰忓懗鐫錛屽湪瀵硅薄鍒涘緩鍚庯紝绔嬪嵆璋冪敤object綾葷殑鏋勯犲嚱鏁幫紝瀵瑰垰鐢熸垚鐨勫璞¤繘琛屽垵濮嬪寲銆傛瀯閫犲嚱鏁版槸鑲畾鏈夌殑銆傚鏋滀綘娌″啓錛孞ava浼氱粰浣犺ˉ涓婁竴涓粯璁ょ殑鏋勯犲嚱鏁般?br />
3錛夊乏杈圭殑“object a”鍒涘緩浜嗕竴涓猳bject綾誨紩鐢ㄥ彉閲忋傛墍璋搊bject綾誨紩鐢紝灝辨槸浠ュ悗鍙互鐢ㄦ潵鎸囧悜object瀵硅薄鐨勫璞″紩鐢ㄣ?br />
4錛?#8220;=”鎿嶄綔絎︿嬌瀵硅薄寮曠敤鎸囧悜鍒氬垱寤虹殑閭d釜object瀵硅薄銆傛垜浠彲浠ユ妸榪欐潯璇彞鎷嗘垚涓ら儴鍒嗭細
object a;
a= new object();
鏁堟灉鏄竴鏍風(fēng)殑銆傝繖鏍峰啓錛屽氨姣旇緝娓呮浜嗭紝鏈変袱涓疄浣擄細涓鏄璞″紩鐢ㄥ彉閲忥紝涓鏄璞℃湰韜?nbsp;
鍦ㄥ爢絀洪棿閲屽垱寤虹殑瀹炰綋錛屼笌鍦ㄦ暟鎹浠ュ強鏍堢┖闂撮噷鍒涘緩鐨勫疄浣撲笉鍚屻傚敖綆″畠浠篃鏄‘紜疄瀹炲瓨鍦ㄧ殑瀹炰綋錛屼絾鏄紝鎴戜滑鐪嬩笉瑙侊紝涔熸懜涓嶇潃銆?br />
涓嶄粎濡傛錛屾垜浠粩緇嗙爺絀朵竴涓嬬浜屽彞錛屾壘鎵懼垰鍒涘緩鐨勫璞″彨浠涔堝悕瀛楋紵鏈変漢璇達紝瀹冨彨“object”銆備笉瀵癸紝“object”鏄被錛堝璞$殑鍒涘緩妯℃澘錛夌殑鍚嶅瓧銆備竴涓猳bject綾誨彲浠ユ嵁姝ゅ垱寤哄嚭鏃犳暟涓璞★紝榪欎簺瀵硅薄涓嶅彲鑳藉叏鍙?#8220;object”銆?nbsp;
瀵硅薄榪炲悕閮芥病鏈夛紝娌℃硶鐩存帴璁塊棶瀹冦傛垜浠彧鑳介氳繃瀵硅薄寮曠敤鏉ラ棿鎺ヨ闂璞°?nbsp;
涓轟簡褰㈣薄鍦拌鏄庡璞°佸紩鐢ㄥ強瀹冧滑涔嬮棿鐨勫叧緋伙紝
涓轟簡璇存槑榪欎釜鍏崇郴,鎴戝湪緗戜笂鐪嬪埌鍒漢鐨勬瘮鍠繪尯濂界殑鎴戜篃寮曠敤涓涓?
瀵硅薄濂芥瘮鏄竴鍙緢澶х殑姘旂悆錛屽ぇ鍒版垜浠姄涓嶄綇瀹冦傚紩鐢ㄥ彉閲忔槸涓鏍圭懷錛屽彲浠ョ敤鏉ョ郴姹界悆銆?nbsp; 濡傛灉鍙墽琛屼簡絎竴鏉¤鍙ワ紝榪樻病鎵ц絎簩鏉★紝姝ゆ椂鍒涘緩鐨勫紩鐢ㄥ彉閲廰榪樻病鎸囧悜浠諱綍涓涓璞★紝瀹冪殑鍊兼槸null銆傚紩鐢ㄥ彉閲忓彲浠ユ寚鍚戞煇涓璞★紝鎴栬呬負null銆傚畠鏄竴鏍圭懷錛屼竴鏍硅繕娌℃湁緋諱笂浠諱綍涓涓苯鐞冪殑緇熾傛墽琛屼簡絎簩鍙ュ悗錛屼竴鍙柊姹界悆鍋氬嚭鏉ヤ簡錛屽茍琚郴鍦╝榪欐牴緇充笂銆傛垜浠姄浣忚繖鏍圭懷錛屽氨絳変簬鎶撲綇浜嗛偅鍙苯鐞冦傚啀鏉ヤ竴鍙ワ細 object a1;灝卞張鍋氫簡涓鏍圭懷錛岃繕娌$郴涓婃苯鐞冦傚鏋滃啀鍔犱竴鍙ワ細 a1= a;緋諱笂浜嗐傝繖閲岋紝鍙戠敓浜嗗鍒惰涓恒備絾鏄紝瑕佽鏄庣殑鏄紝瀵硅薄鏈韓騫舵病鏈夎澶嶅埗錛岃澶嶅埗鐨勫彧鏄璞″紩鐢ㄣ傜粨鏋滄槸錛宎1涔熸寚鍚戜簡a鎵鎸囧悜鐨勫璞°備袱鏍圭懷緋葷殑鏄悓涓鍙苯鐞冦?nbsp; 濡傛灉鐢ㄤ笅鍙ュ啀鍒涘緩涓涓璞★細a1= new object();鍒欏紩鐢ㄥ彉閲廰1鏀規(guī)寚鍚戠浜屼釜瀵硅薄銆?nbsp; 浠庝互涓婂彊榪板啀鎺ㄦ紨涓嬪幓錛?br />
鎴戜滑鍙互鑾峰緱浠ヤ笅緇撹錛氾紙1錛変竴涓璞″紩鐢ㄥ彲浠ユ寚鍚?涓垨1涓璞★紙涓鏍圭懷瀛愬彲浠ヤ笉緋繪苯鐞冿紝涔熷彲浠ョ郴涓涓苯鐞冿級錛涳紙2錛変竴涓璞″彲浠ユ湁N涓紩鐢ㄦ寚鍚戝畠錛堝彲浠ユ湁N鏉$懷瀛愮郴浣忎竴涓苯鐞冿級銆?nbsp;
濡傛灉鍐嶆潵涓嬮潰璇彞錛?nbsp; a= a1;鎸変笂闈㈢殑鎺ㄦ柇錛宎涔熸寚鍚戜簡絎簩涓璞°傝繖涓病闂銆傞棶棰樻槸絎竴涓璞″憿錛熸病鏈変竴鏉$懷瀛愮郴浣忓畠錛屽畠椋炰簡銆傚鏁頒功閲岃錛屽畠琚獼ava鐨勫瀮鍦懼洖鏀舵満鍒跺洖鏀朵簡銆傝繖涓嶇‘鍒囥傛紜湴璇達紝瀹冨凡鎴愪負鍨冨溇鍥炴敹鏈哄埗鐨勫鐞嗗璞°傝嚦浜庝粈涔堟椂鍊欑湡姝h鍥炴敹錛岄偅瑕佺湅鍨冨溇鍥炴敹鏈哄埗鐨勫績鎯呬簡銆?br />
浜嗚В浜嗕笂闈㈢殑瀵硅薄鐨勫紩鐢?鎴戜滑搴旇鐔熸?zhèn)夊璞′互鍙婂璞$殑寮曠敤浜?鎴戜滑鍥炲ご鍐嶈絎竴棰?/p>
java鍐呴儴鎻愪緵浜嗗嚑涓被,榪欎簺綾誨彲浠ヤ笉浣跨敤new鍏抽敭瀛楁潵鍒濆鍖?渚嬪: string
涓婇潰闂1,鍙互鏀規(guī)垚涓嬮潰鐨勬柟娉?br /> 銆銆1銆?br />
閫氳繃涓婇潰瀵瑰璞″簲鐢ㄧ殑鐞嗚В,灝辯煡閬撳師鍥犱簡.
“>>”榪愮畻絎︿綔甯︾鍙風(fēng)殑浣嶇Щ澶勭悊錛屽畠浣滀綅縐誨鐞嗘椂錛屼細鍏堝皢鍊煎悜鍙崇Щ錛屽茍鍦ㄩ珮浣嶅~0錛岀劧鍚庡皢浣嶇Щ鍚庢墍絀哄嚭鐨勯珮浣嶏紝鍏ㄩ儴鏀規(guī)垚鍘熸潵鐨勬渶楂樹綅鐨勫鹼紙浠h〃姝h礋鍙風(fēng)殑浣嶏級銆備篃灝辨槸璇磋礋鐨勫間綅縐誨悗錛屼粛鐒舵槸璐熺殑鍊鹼紝姣斿錛?
錛?0>>2 =-3
-10= 1111 1111 1111 1111 1111 1111 1111 0110
鍙崇Щ2浣嶏細0011 1111 1111 1111 1111 1111 1111 1101
緇撴灉錛?111 1111 1111 1111 1111 1111 1111 1101 錛堝叏閮ㄥぉ涓婂師鏈鍙蜂綅鐨勫鹼細1錛?
b錛?#8220;>>>”榪愮畻絎?
“>>>”榪愮畻絎︽墍浣滅殑鏄棤絎﹀彿鐨勪綅縐誨鐞嗭紝瀹冧笉浼氬皢鎵澶勭悊鐨勫肩殑鏈楂樹綅瑙嗕負姝h礋絎﹀彿錛屾墍浠ヤ綔浣嶇Щ澶勭悊鏃訛紝浼氱洿鎺ュ湪絀哄嚭鐨勯珮浣嶅~鍏?銆傚綋鎴戜滑瑕佷綔浣嶇Щ鐨勫師濮嬪煎茍闈炰唬琛ㄦ暟鍊兼椂錛堜緥濡傦細琛ㄧず棰滆壊鍥劇礌鐨勫鹼紝鏈楂樹綅騫墮潪姝h礋鍙鳳級錛屽彲鑳藉氨浼氶渶瑕佷嬌鐢ㄦ縐嶆棤絎﹀彿鐨勪綅縐匯傛瘮濡傦細
錛?0>>>2=1073741821
-10=1111 1111 1111 1111 1111 1111 1111 0110 (涓嶇鍘熸潵鐨?#8220;絎﹀彿”浣嶇殑鍊?涓闀夸覆1)錛岀┖涓婄殑鍏ㄩ儴鐩存帴濉?)
0011 1111 1111 1111 1111 1111 1111 1101=1037341821
c錛?#8220;<<”榪愮畻絎?
“>>”榪愮畻絎︾殑鎵浣滅殑涔熸槸鏃犵鍙風(fēng)殑浣嶇Щ澶勭悊錛屽悓鏍峰湴錛屽畠涓嶄細灝嗘墍澶勭悊鐨勫肩殑鏈楂樹綅瑙嗕負姝h礋絎﹀彿錛屽畠浣滀綅縐誨鐞嗘椂錛屼細鐩存帴宸︾Щ騫跺湪浣庝綅濉叆0銆傛墍浠ョ浜岄珮浣嶄互涓嬬殑浣嶈嫢縐誨埌浜嗘渶楂樹綅錛岃鍊肩殑姝h礋鍙兘浼氫笌鍘熸潵鐨勪笉鍚屻?
錛?147483647<<2=4
-2147483647=1000 0000 0000 0000 0000 0000 0000 0001
0000 0000 0000 0000 0000 0000 0000 0100=4
d錛?#8220;<<<”榪愮畻絎?
鎭╋紝褰撶劧浜嗭紝鍦╦ava閲屼笉瀛樺湪瀹冦?/p>
byte鍏抽敭瀛?
byte琛ㄧず瀛楄妭鍨嬶紝瀹冪殑鑼冨洿鍦?-127~ 128涔嬮棿 錛?/p>
byte a=129;榪欐牱瀹氫箟錛岃秴榪囦簡 byte鐨勮寖鍥達紝浼氫笉鍏佽瀹氫箟銆?/p>
浣嗘槸褰?br /> byte a=(byte)3049;榪欑鎯呭喌錛岃繘琛屽己鍒惰漿鎹㈢殑銆傚彲浠ュ畾涔?br /> a鐨勫間負-23;
鍦ㄤ嬌鐢≒reparedStatement榪涜妯$硦鏌ヨ鐨勬椂鍊欏簾浜嗕竴鐣懆鎶橈紝浠ュ墠涓鐩撮兘娌℃湁娉ㄦ剰榪欎釜闂銆備竴鑸儏鍐典笅鎴戜滑榪涜綺劇‘鏌ヨ錛宻ql璇彞綾諱技錛歴elect * from table where name =?錛岀劧鍚庤皟鐢?nbsp;PreparedStatement鐨剆etString絳夋柟娉曠粰錛熸寚瀹氬箋傞偅涔堟ā緋婃煡璇㈢殑鏃跺欏簲璇ユ庝箞鍐欏憿錛熸垜棣栧厛灝濊瘯浜嗭細select * from customer where name like ‘%?%’銆?br />
姝ゆ椂紼嬪簭鎶ラ敊錛屽洜涓猴紵琚寘鍚湪浜嗗崟寮曞彿涓紝PreparedStatement騫朵笉瑙嗗畠涓轟竴涓弬鏁般傚悗鏉ヤ笂緗戞煡浜嗙浉鍏崇殑涓浜涜祫鏂欙紝鍙戠幇鍙互榪欐牱鍐檚elect * from table where name like 錛燂紱浣嗘槸鍦ㄦ寚瀹氬弬鏁扮殑鏃跺欐妸錛熸寚瀹氫負”%”+name+”%”錛宯ame鏄寚瀹氱殑鏌ヨ鏉′歡銆傝繖鏍峰氨O(jiān)K浜嗐?br />
涓鑸儏鍐典笅錛屾垜鎬繪槸娼滄剰璇嗙殑璁ゅ畾浜嗭紵灝辨槸鍙栦唬鎵鎸囧畾鐨勫弬鏁幫紝浣嗘槸瀹為檯涓婃垜浠彲浠ュ鎸囧畾鐨勫弬鏁拌繘琛屼簡涓瀹氱殑鍖呰涔嬪悗鍐嶄紶緇欙紵錛屾瘮濡傝繖閲屾垜浠湪鍙傛暟鐨勫墠鍚庨兘鍔犱簡涓涓?錛岀劧鍚庡啀浼犵粰錛?nbsp;
String expr = "select * from table where url like ?";
pstmt = con.prepareStatement(expr);
String a="a";
pstmt.setString(1, "%"+a+"%");//鑷姩娣誨姞鍗曞紩鍙?nbsp;錛堝寘瑁呭悗鐨勫弬鏁幫級
pstmt.execute();
System.out.println(pstmt.toString());//鎵撳嵃sql
//浼氶粯璁ょ敓鎴恠ql錛?select * from table where url like '%http%'