JavaWeb開發第8章标準标簽庫(JSTL)之四 JSTL函數 JSTL8.7JSTL函數

???????? 涓轟?绠?????SP椤甸?㈡??浣?瀛?绗?覆锛?JSTL涓???渚?浜?涓?濂?EL??瀹?涔??芥?幫?杩?浜??芥?闆????浜?JSP椤甸?㈠?朵???缁?甯歌??ㄥ?扮??瀛?绗?覆??浣???渚?濡?锛?fn:toLowerCase灏?瀛?绗?覆涓???瀛?绗???涓哄???锛?fn:indexOf杩???涓?涓???瀹?瀛?绗?覆?ㄥ???涓?瀛?绗?覆涓?绗?涓?娆″?虹?扮??绱㈠?浣?缃???

JSTL涓???渚???EL??瀹?涔??芥?闆?椤誨??L琛ㄨ揪寮?涓?浣跨???渚?濡?锛?${fn:toUpperCase("www.it315.org")}??

? JSTL8.7JSTL?芥?奧???

8.7.1? fn:toLowerCase?芥??/h2>

fn:toLowerCase?芥?闆?涓?涓?瀛?绗?覆涓???????????瀛?绗?漿??負灏???褰㈠?锛?骞惰???杞??㈠????瀛?绗?覆锛?瀹??ユ?朵?涓?瀛?绗?覆绫誨???????般??

fn:toLowerCase?芥?扮??搴??ㄤ婦渚?锛?

l????????fn:toLowerCase("Www.IT315.org") ??杩????間負瀛?绗?覆??www.it315.org??

l????????fn:toLowerCase("")??杩????間負绌哄??绗?覆

8.7.2? fn:toUpperCase?芥??/h3>

fn:toUpperCase?芥?闆?涓?涓?瀛?绗?覆涓???????????瀛?绗?漿??負澶у??褰㈠?锛?骞惰???杞??㈠????瀛?绗?覆锛?瀹??ユ?朵?涓?瀛?绗?覆绫誨???????般??

fn:toUpperCase?芥?扮??搴??ㄤ婦渚?锛?

l????????fn:toUpperCase("Www.IT315.org") ??杩????間負瀛?绗?覆??WWW.IT315.ORG??

l????????fn:toUpperCase("")??杩????間負绌哄??绗?覆

? fn:trim8.73JSTL?芥??/h2>

fn:trim?芥?闆???や?涓?瀛?绗?覆??棣?灏劇??绌烘?鹼?骞惰??????ょ┖?煎????缁???瀛?绗?覆锛?瀹??ユ?朵?涓?瀛?绗?覆绫誨???????般????瑕?娉ㄦ??????锛?fn:trim?芥?頒??藉???ゅ??绗?覆涓??翠?缃???绌烘?箋??

渚?濡?锛?fn:trim("?? www.it?315.org? ") ??杩????間負瀛?绗?覆??www.it? 315.org????

8.7.4? fn:escapeXml?芥??/h2>

fn:escapeXml?芥?闆?瀛?绗?覆涓?????瑕?杩?琛?杞?涔???HTML?規??瀛?绗???琛?.2杩?琛?HTML缂???杞????骞惰???杞??㈠????瀛?绗?覆锛?杩??峰氨??浠ュ?ㄦ?瑙??ㄤ腑?劇ず??TML?規??瀛?绗???fn:escapeXml?芥?版?ユ?朵?涓?瀛?绗?覆绫誨???????般??

渚?濡?锛?杩?琛?????濡?涓?浠ｇ????JSP??浠跺??娴?瑙??ㄥ?璺寵漿?扳??http://www.it315.org??椤甸???杩?????涓鴻?浜?浠ｇ??琚?娴?瑙??ㄤ?涓?TML??绛捐В???ц?锛?

<meta http-equiv="refresh" content="0;url=http://www.it315.org"/>

濡?????n:escapeXml?芥?闆???涓??㈢??浠ｇ??锛?杩?琛?JSP??浠跺??灏卞?ㄦ?瑙??ㄧ???ｈ??鴻?琛?浠ｇ??锛?渚?绋?8-54??浣跨??n:escapeXml?芥?闆???涓??㈢??浠ｇ????渚?瀛?绋?搴???

渚?绋?8-54? fn_escapeXml.jsp

?

<%@ taglibprefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>

${fn:escapeXml('<metahttp-equiv="refresh"

????????????? content="0;url=http://www.it315.org"/>')}

?

fn_escapeXml.jsp椤甸?㈢??杩?琛?缁???濡???.46??绀恒??

8.75??fn:length?芥??/h2>

fn:length?芥?扮?ㄤ?杩???涓?涓????????扮?瀵矽薄涓?????????绱???涓??幫???杩???涓?涓?瀛?绗?覆涓???????瀛?绗???涓??幫?杩????間負int绫誨????fn:length?芥?版?ユ?朵?涓????幫?杩?涓????闆??浠ユ??<c:forEach>??绛劇??items灞??ф??????浠諱?绫誨??锛?????浠繪??绫誨?????扮???java.util.Collection??java.util.Iterator??java.util.Enumeration??java.util.Map绛?绫葷??瀹?渚?瀵矽薄??瀛?绗?覆??

濡???fn:length?芥?扮?????頒負null????????绱?涓??頒負0?????????扮?瀵矽薄锛????芥?拌???0锛?濡??????版??绌哄??绗?覆锛????芥?拌???0??渚?绋?8-55??浣跨??n:length?芥?扮??瀹?渚?绋?搴???

渚?绋?8-55? fn_length.jsp

?

<%@ taglibprefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>

<%@ pagecontentType="text/html;charset=gb2312" %>

<%@ pageimport="java.util.*, org.it315.UserBean" %>

<%

?????? Collection users = new ArrayList();

?????? for(int i=0; i<5; i++)

?????? {

????????????? UserBean user = new UserBean();

????????????? user.setUserName("user"+ i);

????????????? user.setPassword("guest"+ i);

????????????? users.add(user);

?????? }

?????? session.setAttribute("users",users);

%>

There are${fn:length(users)} users online.<hr />

瀛?绗?覆??www.it315.org??涓?????${fn:length("www.it315.org")} 涓?瀛?绗?

?

fn_length.jsp椤甸?㈢??杩?琛?缁???濡???.47??绀恒??

8.76??fn:split?芥??/h2>

fn:split?芥?頒互??瀹?瀛?绗?覆浣?涓哄????绗??灏?涓?涓?瀛?绗?覆???叉??瀛?绗?覆?扮?骞惰???杩?涓?瀛?绗?覆?扮???fn:split?芥?版?ユ?朵袱涓?瀛?绗?覆绫誨???????幫?绗?涓?涓????拌〃绀鴻????茬??瀛?绗?覆锛?绗?浜?涓????拌〃绀轟?涓哄????绗???瀛?绗?覆??

l????????fn:split?芥?闆????ava.util.StringTokenizer绫誨???插??绗?覆????浣?锛?寰??扮??瀛?绗?覆?扮?涓?????瀛?绗?覆??绱?涓?????????绗???韬?锛?渚?濡?锛?fn:split("www.it315.org",".")[1]??杩????間負瀛?绗?覆??it315????

l????????濡???绗?涓?涓????版??绌哄??绗?覆锛???fn:split?芥?拌?????瀛?绗?覆?扮?涓???????绌哄??绗?覆杩?涓?涓???绱?锛?渚?濡?锛?fn:split("",".")[0]??杩????間負绌哄??绗?覆??

l????????濡???绗?浜?涓????版??绌哄??绗?覆锛????芥?拌?????瀛?绗?覆?扮?涓???????婧?瀛?绗?覆杩?涓?涓???绱?锛?渚?濡?锛?fn:split("www.it315.org","")[0]??杩????間負瀛?绗?覆??www.it315.org??锛?fn:split("www.it315.org", "")[1]??杩????間負绌哄??绗?覆??

8.77??fn:join?芥??/h2>

fn:join?芥?頒互涓?涓?瀛?绗?覆浣?涓哄????绗??灏?涓?涓?瀛?绗?覆?扮?涓?????????绱???骞朵負涓?涓?瀛?绗?覆骞惰?????骞跺????缁???瀛?绗?覆??fn:join?芥?版?ユ?朵袱涓????幫?绗?涓?涓????版??瑕???浣???瀛?绗?覆?扮?锛?绗?浜?涓????版??浣?涓哄????绗???瀛?绗?覆??

濡???fn:join?芥?扮??绗?浜?涓????版??绌哄??绗?覆锛???fn:join?芥?扮??杩????兼??涓?浣跨?ㄤ換浣?????绗??瀛?绗?覆?扮?涓???????绱?杩??ヨ搗?ョ??缁???瀛?绗?覆??

fn:join?芥?扮??搴??ㄤ婦渚?锛?

l??????????璁?tringArray??淇?瀛???eb??涓???涓?涓?灞??э?瀹?琛ㄧず涓?涓??間負{"www","it315","org"}??瀛?绗?覆?扮?锛???fn:join(stringArray, ".")杩???瀛?绗?覆??www.it315.org??

l????????fn:join(fn:split("www,it315,org",","), ".") ??杩????間負瀛?绗?覆??www.it315.org??

8.78??fn:indexOf?芥??/h2>

fn:indexOf?芥?拌?????瀹?瀛?绗?覆?ㄤ?涓?瀛?绗?覆涓?绗?涓?娆″?虹?扮??绱㈠??鹼?杩????間負int绫誨????fn:indexOf?芥?版?ユ?朵袱涓?瀛?绗?覆绫誨???????幫?濡???绗?涓?涓????闆??绗?覆涓?????绗?浜?涓????闆??绗?覆锛??ｄ?锛?涓?绠＄??浜?涓????闆??绗?覆?ㄧ??涓?涓????闆??绗?覆涓??虹?闆??娆★?fn:indexOf?芥?版?繪??杩???绗?涓?娆″?虹?扮??绱㈠??鹼?濡???绗?涓?涓????頒腑涓?????绗?浜?涓????幫???fn:indexOf?芥?拌???-1??濡???绗?浜?涓????頒負绌哄??绗?覆锛???fn:indexOf?芥?版?繪??杩???0??

fn:indexOf?芥?扮??搴??ㄤ婦渚?锛?

l????????fn:indexOf("www.it315.org","t3")??杩????間負5

l????????fn:indexOf("www.it315.org","aaa")??杩????間負 -1

l????????fn:indexOf("www.it315.org","")??杩????間負0

8.79??fn:contains?芥??/h2>

fn:contains?芥?版?娴?涓?涓?瀛?绗?覆涓???????????瀹???瀛?绗?覆锛?杩????間負甯?灏?绫誨????fn:contains?芥?闆?ㄦ??杈?涓や釜瀛?绗?覆?????哥???舵??澶у???????????

fn:contains?芥?版?ユ?朵袱涓?瀛?绗?覆绫誨???????幫?濡???绗?涓?涓????闆??绗?覆涓?????绗?浜?涓????闆??绗?覆锛???fn:contains?芥?拌???true锛?????杩???false??濡???绗?浜?涓????扮???間負绌哄??绗?覆锛???fn:contains?芥?版?繪??杩???true??瀹???涓?锛?fn:contains(string,substring)绛?浠蜂?fn:indexOf(string,substring) != -1??

fn:contains?芥?扮??搴??ㄤ婦渚?锛?

l????????fn:contains("www.it315.org", "org")??杩????間負true

l????????fn:contains("www.it315.org","Org")??杩????間負false

l????????fn:contains("", "")??杩????間負true

8.8??fn:containsIgnoreCase?芥??/h2>

fn:containsIgnoreCase?芥?版?娴?涓?涓?瀛?绗?覆涓???????????瀹???瀛?绗?覆锛??ㄦ??杈?涓や釜瀛?绗?覆?????哥???跺ぇ灏???涓???????fn:containsIgnoreCase?芥?扮?????闆??杩????肩??绫誨???戒?fn:contains?芥?扮?稿??锛??????????ㄦ??杈?涓や釜瀛?绗?覆?????哥???朵?????瀛?绗???澶у???锛???????????瀛?绗???澶у???锛?fn:containsIgnoreCase(string,substring)绛?浠蜂?fn:contains(fn:toUpperCase(string),fn:toUpperCase(substring))??

fn:containsIgnoreCase?芥?扮??搴??ㄤ婦渚?锛?

l????????fn:containsIgnoreCase("www.it315.org","Org") ??杩????間負 true

l????????fn:containsIgnoreCase (fn:toUpperCase("www.it315.org"),fn:toUpperCase("Org"))??杩????間負true

8.81??fn:startsWith?芥??/h2>

fn:startsWith?芥?扮?ㄤ?妫?娴?涓?涓?瀛?绗?覆??????浠ユ??瀹?瀛?绗?覆寮?濮???锛?杩????間負甯?灏?绫誨????

fn:startsWith?芥?版?ユ?朵袱涓?瀛?绗?覆绫誨???????幫?濡???绗?涓?涓????闆??绗?覆浠ョ??浜?涓????闆??绗?覆寮?濮?锛????芥?拌???true锛??????芥?拌???false??濡???绗?浜?涓????頒負绌哄??绗?覆锛???fn:startsWith?芥?版?繪??杩???true??瀹???涓?锛?fn:startsWith(string, prefix)绛?浠蜂?琛ㄨ揪寮?fn:indexOf(string, prefix) == 0??

fn:startsWith?芥?扮??搴??ㄤ婦渚?锛?

l????????fn:startsWith("www.it315.org","it315")??杩????間負false

l????????fn:startsWith("www.it315.org","www")??杩????間負true

l????????fn:startsWith("www.it315.org","")??杩????間負true

8.82??fn:endsWith?芥??/h3>

fn:endsWith?芥?扮?ㄤ?妫?娴?涓?涓?瀛?绗?覆??????浠ユ??瀹?瀛?绗?覆缁?????锛?杩????間負甯?灏?绫誨????

fn:endsWith?芥?版?ユ?朵袱涓?瀛?绗?覆绫誨???????幫?濡???绗?涓?涓????闆??绗?覆浠ョ??浜?涓????闆??绗?覆缁???锛????芥?拌???true锛??????芥?拌???false??濡???绗?浜?涓????頒負绌哄??绗?覆锛???fn:endsWith?芥?版?繪??杩???true??

fn:endsWith?芥?扮??搴??ㄤ婦渚?锛?

l????????fn:endsWith("www.it315.org","it315")??杩????間負false

l????????fn:endsWith("www.it315.org","org")??杩????間負true

l????????fn:endsWith("www.it315.org","")??杩????間負true

8.83??fn:replace?芥??/h3>

fn:replace?芥?闆?涓?涓?瀛?绗?覆涓?????????瀹?瀛?瀛?绗?覆?挎??負?跺??????瀹?瀛?绗?覆锛?骞惰????挎?㈠????缁???瀛?绗?覆??fn:replace?規??ユ?朵?涓?瀛?绗?覆绫誨???????幫?绗?涓?涓????拌〃绀鴻???浣???婧?瀛?绗?覆锛?绗?浜?涓????拌〃绀烘?瀛?绗?覆涓?瑕?琚??挎?㈢??瀛?瀛?绗?覆锛?绗?涓?涓????拌〃绀鴻?琚??挎?㈡????瀛?绗?覆??

fn:replace?芥?版???т??㈢??璇存???ц?瀛?绗?覆???挎?㈡??浣?锛?

锛?1锛?婧?瀛?绗?覆涓???????绗?浜?涓????版??瀹???瀛?瀛?绗?覆?借??挎?㈡??绗?涓?涓????版??瀹???瀛?绗?覆锛?濡????挎?㈠????缁???瀛?绗?覆涓?????绗?浜?涓????版??瀹???瀛?瀛?绗?覆锛???涓???杩?琛??挎????渚?濡?锛?

l????????fn:replace("www it315 org", " ", ".")??杩????間負瀛?绗?覆??www.it315.org??

l????????fn:replace("ddabccff", "abc", "ab")??杩????間負瀛?绗?覆??ddabcff??锛?杩?涓?瀛?绗?覆涓?杩?????瀛?绗?覆??abc??锛?浣?涓????ц??挎?㈡??浣?

锛?2锛?濡???绗?涓?涓????版??绌哄??绗?覆锛???fn:replace?芥?拌???绌哄??绗?覆锛?渚?濡?锛?fn:replace("", " ",".")??杩????間負绌哄??绗?覆??

锛?3锛?濡???绗?浜?涓????版??绌哄??绗?覆锛???fn:replace?芥?頒??ц?浠諱??挎?㈡??浣?锛?杩???绗?涓?涓????版??瀹???瀛?绗?覆??渚?濡?锛?fn:replace("www.it315.org","", " ") ??杩????間負瀛?绗?覆??www.it315.org????

锛?4锛?濡???绗?涓?涓????版??绌哄??绗?覆锛???fn:replace?芥?闆???ゆ?瀛?绗?覆涓???????绗?浜?涓????版??瀹???瀛?瀛?绗?覆??渚?濡?锛?fn:replace("www.it315.org",".", "")??杩????間負瀛?绗?覆??wwwit315org????

8.84??fn:substring?芥??/h3>

fn:substring?芥?扮?ㄤ?????涓?涓?瀛?绗?覆??瀛?瀛?绗?覆骞惰????????扮??瀛?瀛?绗?覆??fn:substring?芥?版?ユ?朵?涓????幫?绗?涓?涓????版???ㄤ???瀹?瑕???浣???婧?瀛?绗?覆锛?绗?浜?涓????版???ㄤ???瀹?????瀛?瀛?绗?覆寮?濮???绱㈠??鹼?绗?涓?涓????版???ㄤ???瀹?????瀛?瀛?绗?覆缁?????绱㈠??鹼?绗?浜?涓????闆??绗?涓?涓????伴?芥??int绫誨??锛??跺?奸?戒?0寮?濮???

fn:substring?芥?版???т??㈢??璇存??????涓?涓?瀛?绗?覆??瀛?瀛?绗?覆锛?

l????????濡???绗?浜?涓????扮???煎ぇ浜???绛?浜?婧?瀛?绗?覆涓???????瀛?绗?釜?幫???fn:substring?芥?拌???绌哄??绗?覆锛?

l????????濡???绗?浜?涓????扮???煎?浜?0锛???灏??跺?艱?劇疆涓?锛?

l????????濡???绗?涓?涓????扮???煎?浜?0??澶т?婧?瀛?绗?覆涓???????瀛?绗?釜?幫????????版?瀛?绗?覆??缁?灏劇??瀛?绗??

l????????濡???绗?涓?涓????扮???煎?浜?绗?浜?涓????扮???鹼???fn:substring?芥?拌???绌哄??绗?覆??

fn:substring?芥?扮??搴??ㄤ婦渚?锛?瀛?绗?覆??www.it315.org??涓?????13涓?瀛?绗??锛?

l????????fn:substring("www.it315.org", 4, 9) ??杩????間負瀛?绗?覆??it315??

l????????fn:substring("www.it315.org", 13, 14)杩???绌哄??绗?覆

l????????fn:substring("www.it315.org", -1, 9) ??杩????間負瀛?绗?覆??www.it315??

l????????fn:substring("www.it315.org", 4, -1) ??杩????間負瀛?绗?覆??it315.org??

l????????fn:substring("www.it315.org", 4, 13) ??杩????間負瀛?绗?覆??it315.org??

l????????fn:substring("www.it315.org", 4, 3) 杩???绌哄??绗?覆

8.84??fn:substringAfter?芥??/h3>

fn:substringAfter?芥?扮?ㄤ?????骞惰???涓?涓?瀛?绗?覆涓?????瀹?瀛?瀛?绗?覆绗?涓?娆″?虹?頒?????瀛?瀛?绗?覆??fn:substringAfter?芥?版?ユ?朵袱涓?瀛?绗?覆绫誨???????幫?绗?涓?涓????拌〃绀鴻???浣???婧?瀛?绗?覆锛?绗?浜?涓????拌〃绀烘??瀹???瀛?瀛?绗?覆锛?渚?濡?锛?fn:substringAfter("www.it315.org",".")??杩????間負瀛?绗?覆??it315.org????

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