blocks|key|3798315|text|这是我找到的一个解决方案。不过，它看起来并不是很优雅：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3798316|<%25@+taglib+prefix="fn"+uri="http://java.sun.com/jsp/jstl/functions"+%25>
<%25+pageContext.setAttribute("newLineChar",+"\n");+%25>

${fn:replace(item.comments,+newLineChar,+";+")}|code-block|syntax|javascript|3798317|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is a solution I found. It doesn't seem very elegant, though:

<pre><code>&lt;%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %&gt;
&lt;% pageContext.setAttribute("newLineChar", "\n"); %&gt;

${fn:replace(item.comments, newLineChar, "; ")}
</code></pre>

blocks|key|2953135|text|只需使用fn:replace()函数将\n替换为;即可。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2953136|${fn:replace(data,+'\n',+';')}|code-block|syntax|javascript|2953137|如果你使用的是Apache的EL实现而不是Oracle的EL参考实现(例如，当你使用Tomcat、TomEE、JBoss等而不是GlassFish、Payara、WildFly、WebSphere等)，那么你需要重新转义反斜杠。|2953138|${fn:replace(data,+'\\n',+';')}|2953139|entityMap^0|4|C|J|2|O|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|P|$]]

Just use <code>fn:replace()</code> function to replace <code>\n</code> by <code>;</code>.

<pre><code>${fn:replace(data, '\n', ';')}
</code></pre>

In case you're using Apache's EL implementation instead of Oracle's EL reference implementation (i.e. when you're using Tomcat, TomEE, JBoss, etc instead of GlassFish, Payara, WildFly, WebSphere, etc), then you need to re-escape the backslash.

<pre><code>${fn:replace(data, '\\n', ';')}
</code></pre>

blocks|key|3799066|text|这与公认的答案类似(因为它使用Java而不是EL表示换行符)，但这里使用元素来设置属性：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3799067|<c:set+var="newline"+value="<%25=+\"\n\"+%25>"+/>
${fn:replace(myAddress,+newline,+"<br+/>")}|code-block|syntax|javascript|3799068|以下代码片段也有效，但元素的第二行不能缩进(可能看起来更难看)：|3799069|++++<c:set+var="newline"+value="
"+/>
++++${fn:replace(myAddress,+newline,+"<br+/>")}|3799070|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

This is similar to the accepted answer (because it is using Java to represent the newline rather than EL) but here the &lt;c:set/&gt; element is used to set the attribute:

<pre><code>&lt;c:set var="newline" value="&lt;%= \"\n\" %&gt;" /&gt;
${fn:replace(myAddress, newline, "&lt;br /&gt;")}
</code></pre>

The following snippet also works, but the second line of the &lt;c:set/&gt; element cannot be indented (and may look uglier):

<pre><code> &lt;c:set var="newline" value="
" /&gt;&lt;!--this line can't be indented --&gt;
 ${fn:replace(myAddress, newline, "&lt;br /&gt;")}
</code></pre>

blocks|key|3798518|text|这个解决方案比您自己的直接设置pagecontext属性的解决方案更好。您应该使用<c:set>标记来执行以下操作：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3798519|<%25@+taglib+prefix="c"+uri="http://java.sun.com/jsp/jstl/core"+%25>
<%25@+taglib+prefix="fn"+uri="http://java.sun.com/jsp/jstl/functions"+%25>

<c:set+var="newLine"+value="\n"/>
${fn:replace(data,+newLine,+";+")}|code-block|syntax|javascript|3798520|顺便说一句：${fn:replace(data,+"\n",+";")}不工作。|3798521|entityMap^0|15|7|0|0|6|U|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

This solution is more elegant than your own solution which is setting the pagecontext attribute directly. You should use the <code>&lt;c:set&gt;</code> tag for this:

<pre><code>&lt;%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %&gt;
&lt;%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %&gt;

&lt;c:set var="newLine" value="\n"/&gt;
${fn:replace(data, newLine, "; ")}
</code></pre>

BTW: <code>${fn:replace(data, "\n", ";")}</code> does NOT work.

blocks|key|5208877|text|您可以创建自己的JSP函数。http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JSPTags6.html|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|5208878|这大致就是您需要做的。|5208879|创建标记库描述符文件|5208880|/src/META-INF/sf.tld|5208881|<?xml+version="1.0"+encoding="UTF-8"?>
<taglib+version="2.0"+xmlns="http://java.sun.com/xml/ns/j2ee"+
++xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"+
++xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee+web-jsptaglibrary_2_0.xsd">
++<tlib-version>1.0</tlib-version>
++<short-name>sf</short-name>
++<uri>http://www.stackoverflow.com</uri>
++<function>
++++<name>clean</name>
++++<function-class>com.stackoverflow.web.tag.function.TagUtils</function-class>
++++<function-signature>
++++++java.lang.String+clean(java.lang.String)
++++</function-signature>
++</function>
</taglib>|code-block|syntax|javascript|5208882|为函数逻辑创建一个Java类。|5208883|com.stackoverflow.web.tag.function.TagUtils|5208884|package+com.stackoverflow.web.tag.function;

import+javax.servlet.jsp.tagext.TagSupport;

public+class+TagUtils+extends+TagSupport+{
++public+static+String+clean(String+comment)+{
++++return+comment.replaceAll("\n",+";+");
++}
}|5208885|在JSP中，您可以通过以下方式访问函数。|5208886|<%25@+taglib+prefix="sf"+uri="http://www.stackoverflow.com"%25>
${sf:clean(item.comments)}|5208887|entityMap|0|LINK|mutability|MUTABLE|url|http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JSPTags6.html^0|E|1O|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@$A|17|B|18|1|19]]|C|$]]|$1|D|3|E|5|6|7|1A|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|1B|8|@]|9|@]|C|$]]|$1|H|3|I|5|6|7|1C|8|@]|9|@]|C|$]]|$1|J|3|K|5|L|7|1D|8|@]|9|@]|C|$M|N]]|$1|O|3|P|5|6|7|1E|8|@]|9|@]|C|$]]|$1|Q|3|R|5|6|7|1F|8|@]|9|@]|C|$]]|$1|S|3|T|5|L|7|1G|8|@]|9|@]|C|$M|N]]|$1|U|3|V|5|6|7|1H|8|@]|9|@]|C|$]]|$1|W|3|X|5|L|7|1I|8|@]|9|@]|C|$M|N]]|$1|Y|3|-4|5|6|7|1J|8|@]|9|@]|C|$]]]|Z|$10|$5|11|12|13|C|$14|15]]]]

You could create your own JSP function. 
<a href="http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JSPTags6.html" rel="nofollow noreferrer">http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JSPTags6.html</a>

This is roughly what you need to do.

Create a tag library descriptor file 
/src/META-INF/sf.tld

<pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;taglib version="2.0" xmlns="http://java.sun.com/xml/ns/j2ee" 
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-jsptaglibrary_2_0.xsd"&gt;
 &lt;tlib-version&gt;1.0&lt;/tlib-version&gt;
 &lt;short-name&gt;sf&lt;/short-name&gt;
 &lt;uri&gt;http://www.stackoverflow.com&lt;/uri&gt;
 &lt;function&gt;
 &lt;name&gt;clean&lt;/name&gt;
 &lt;function-class&gt;com.stackoverflow.web.tag.function.TagUtils&lt;/function-class&gt;
 &lt;function-signature&gt;
 java.lang.String clean(java.lang.String)
 &lt;/function-signature&gt;
 &lt;/function&gt;
&lt;/taglib&gt;
</code></pre>

Create a Java class for the functions logic. 
com.stackoverflow.web.tag.function.TagUtils

<pre><code>package com.stackoverflow.web.tag.function;

import javax.servlet.jsp.tagext.TagSupport;

public class TagUtils extends TagSupport {
 public static String clean(String comment) {
 return comment.replaceAll("\n", "; ");
 }
}
</code></pre>

In your JSP you can access your function in the following way.

<pre><code>&lt;%@ taglib prefix="sf" uri="http://www.stackoverflow.com"%&gt;
${sf:clean(item.comments)}
</code></pre>

blocks|key|5209088|text|这对我不起作用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5209089|<c:set+var="newline"+value="\n"/>
${fn:replace(data,+newLine,+";+")}|code-block|syntax|javascript|5209090|这样做：|5209091|<%25+pageContext.setAttribute("newLineChar",+"\n");+%25>+
${fn:replace(item.comments,+newLineChar,+";+")}|5209092|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

This does not work for me:

<pre><code>&lt;c:set var="newline" value="\n"/&gt;
${fn:replace(data, newLine, "; ")}
</code></pre>

This does:

<pre><code>&lt;% pageContext.setAttribute("newLineChar", "\n"); %&gt; 
${fn:replace(item.comments, newLineChar, "; ")}
</code></pre>

blocks|key|5209421|text|如果你真正需要的是一个\n符号，你可以使用here的建议|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|5209422|${fn:replace(text,+"
",+" ")}|code-block|syntax|javascript|5209423|或|5209424|<c:set+var="nl"+value="
"+/><%25--+this+is+a+new+line+--%25>|5209425|这包括字符串字面量中的新行。|5209426|entityMap|0|LINK|mutability|MUTABLE|url|http://www.coderanch.com/t/283187/JSP/java/New-Line-character-JSTL-set#1298039^0|L|4|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

If what you really need is a \n symbol you can use the advice from <a href="http://www.coderanch.com/t/283187/JSP/java/New-Line-character-JSTL-set#1298039" rel="nofollow">here</a>:

<pre><code>${fn:replace(text, "
", "&lt;br/&gt;")}
</code></pre>

or

<pre><code>&lt;c:set var="nl" value="
" /&gt;&lt;%-- this is a new line --%&gt;
</code></pre>

This includes the new line in your string literal.

blocks|key|729123|text|\n不表示EL表达式中的换行符。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|729124|将pageContext属性设置为换行符，然后将其与JSTL的fn:replace函数一起使用的解决方案是有效的。|offset|length|style|CODE|729125|但是，我更喜欢使用Jakarta+String+Tab+Library来解决这个问题：|729126|<%25@+taglib+prefix="str"+uri="http://jakarta.apache.org/taglibs/string-1.1"+%25>
...
<str:replace+var="result"+replace="~n"+with=";"+newlineToken="~n">
Text+containing+newlines
</str:replace>
...|code-block|syntax|javascript|729127|您可以对newlineToken使用任何您想要的东西；"~n“不太可能出现在我正在进行替换的文本中，所以这对我来说是一个合理的选择。|729128|entityMap^0|0|1|B|V|A|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@$D|U|E|V|F|G]|$D|W|E|X|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|Y|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|Z|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|R|$]]

\n does not represent the newline character in an EL expression.

The solution which sets a <code>pageContext</code> attribute to the newline character and then uses it with JSTL's <code>fn:replace</code> function does work.

However, I prefer to use the Jakarta String Tab Library to solve this problem:

<pre><code>&lt;%@ taglib prefix="str" uri="http://jakarta.apache.org/taglibs/string-1.1" %&gt;
...
&lt;str:replace var="result" replace="~n" with=";" newlineToken="~n"&gt;
Text containing newlines
&lt;/str:replace&gt;
...
</code></pre>

You can use whatever you want for the newlineToken; "~n" is unlikely to show up in the text I'm doing the replacement on, so it was a reasonable choice for me.

blocks|key|3799094|text|对于JSP+EL，这是一个有效的解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3799095|"${fn:split(string1,+Character.valueOf(10))}"|code-block|syntax|javascript|3799096|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is a valid solution for the JSP EL:

<pre><code>"${fn:split(string1, Character.valueOf(10))}"
</code></pre>

blocks|key|3798762|text|更简单：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3798763|<str:replace+var="your_Var_replaced"+replace="\n"+with="Your+ney+caracter"+newlineToken="\n">${your_Var_to_replaced}</str:replace>++|code-block|syntax|javascript|3798764|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

More easily:

<pre><code>&lt;str:replace var="your_Var_replaced" replace="\n" with="Your ney caracter" newlineToken="\n"&gt;${your_Var_to_replaced}&lt;/str:replace&gt; 
</code></pre>

blocks|key|3798365|text|您可以编写自己的JSP函数来进行替换。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3798366|这意味着你最终会得到类似这样的结果：|3798367|<%25@+taglib+prefix="ns"+uri="..."+%25>
...
${ns:replace(data)}|code-block|syntax|javascript|3798368|其中JSP是您定义的名称空间前缀，replace是您的ns函数。|offset|length|style|CODE|3798369|这些函数很容易实现(它们只是一个静态方法)，尽管目前我似乎找不到一个很好的参考来编写它们。|3798370|entityMap^0|0|0|0|H|7|R|2|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|V|8|@$K|W|L|X|M|N]|$K|Y|L|Z|M|N]]|9|@]|A|$]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|R|$]]

You could write your own JSP function to do the replacement.

This means you'd end up with something like:

<pre><code>&lt;%@ taglib prefix="ns" uri="..." %&gt;
...
${ns:replace(data)}
</code></pre>

Where <code>ns</code> is a namespace prefix you define and <code>replace</code> is your JSP function.

These functions are pretty easy to implement (they're just a static method) although I can't seem to find a good reference for writing these at the moment.

blocks|key|733736|text|在设置var时的值中，在双引号之间按ENTER键。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|733737|​|733738|${fn:replace(data，newLineChar，";")}|733739|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

In the value while setting the var, press ENTER between the double quotes.



${fn:replace(data, newLineChar, ";")}

blocks|key|729227|text|顺便说一句，我在解决这个问题时偶然发现了这篇文章：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|729228|JSTL中的多行字符串被添加为文本区域的title属性。然后Javascript将其添加为文本区域的默认文本。为了在焦点上清除此文本，值需要等于标题...但由于许多文本编辑器将\r\n而不是\n放入，因此以下代码将删除不需要的\r：|729229|<%25+pageContext.setAttribute("newLineChar",+"\r");+%25>+
<c:set+var="textAreaDefault"+value="${fn:replace(textAreaDefault,+newLineChar,+'')}"+/>|code-block|syntax|javascript|729230|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

For the record, I came across this post while tackling this problem: 

A multi-line string in JSTL gets added as the title attribute of a textarea. Javascript then adds this as the default text of the textarea. In order to clear this text on focus the value needs to equal the title... but fails as many text-editors put \r\n instead of \n. So the follownig will get rid of the unwanted \r:

<pre><code>&lt;% pageContext.setAttribute("newLineChar", "\r"); %&gt; 
&lt;c:set var="textAreaDefault" value="${fn:replace(textAreaDefault, newLineChar, '')}" /&gt;
</code></pre>

I have a list of bean objects passed into my JSP page, and one of them is a comment field. This field may contain newlines, and I want to replace them with semicolons using JSTL, so that the field can be displayed in a text input. I have found one solution, but it's not very elegant. I'll post below as a possibility.

How can I replace newline characters using JSP and JSTL?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有一个传递到JSP页面的bean对象列表，其中一个是注释字段。该字段可能包含换行符，我希望使用JSTL将它们替换为分号，以便该字段可以在文本输入中显示。我找到了一个解决方案，但它不是很优雅。作为一种可能性，我将在下面发布。

问如何使用JSP和JSTL替换换行符？
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问如何使用JSP和JSTL替换换行符？EN

回答 13

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问如何使用JSP和JSTL替换换行符？
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