HTML：表单不发送UTF-8格式输入 [英] HTML : Form does not send UTF-8 format inputs
问题描述
我曾经访问过关于HTML中UTF-8编码的每一个问题，似乎没有什么能够像预期的那样工作。
我添加了 meta tag：没有任何变化。
我在
JSP文件
<％@ page pageEncoding =UTF-8％>
<％@ taglib uri =http://java.sun.com/jsp/jstl/coreprefix =c％>
<！DOCTYPE html>
< html>
< head>
< meta charset =UTF-8/>
< meta http-equiv =Content-Typecontent =text / html; charset = UTF-8>
< title> Editer les sous-titres< / title>
< / head>
< body>
< form method =postaction =/ Subtitlor / editaccept-charset =UTF-8>
< h3 name =nameOfFile>< c：out value =$ {nameOfFile}/>< / h3>
< input type =hiddenname =nameOfFileid =nameOfFilevalue =$ {nameOfFile}/>
< c：if test =$ {！saved}>
< input value =Enregistrer le travailtype =submitstyle =position：fixed; top：10px; right：10px; />
< / c：if>
< a href =/ Subtitlor /style =position：fixed; top：50px; right：10px;>返回页首< / a>
< c：if test =$ {saved}>
< div style =position：fixed; top：90px; right：10px;>
< c：out value =Travailenregistrédans la base dedonnée/>
< / div>
< / c：if>
< table border =1>
< c：if test =$ {！saved}>
< thead>
< th style =weight：bold>原始行< / th>
< th style =weight：bold>翻译< / th>
< th style =weight：bold>已翻译< / th>
< / thead>
< / c：if>
< c：forEach items =$ {subtitles}var =linevarStatus =status>
< tr>
< td style =text-align：right;>< c：out value =$ {line}/>< / td>
< td>< input type =textname =line $ {status.index}id =line $ {status.index}size =35/>< / td> ;
< td style =text-align：right>< c：out value =$ {lines [status.index] .content}/>< / td>
< / tr>
< / c：forEach>
< / table>
< / form>
< / body>
< / html>
Servlet
pre $
for（int i = 0; i <2; i ++）{
System.out.println（request.getParameter（line+ i） ）;
输出
Et tonpèreet sa soeur
Il ne sera jamais parti。
I添加了
meta标记：没有任何变化。
当页面通过HTTP服务而不是例如时没有任何影响从本地磁盘文件系统（即该页面的URL http：// ... 而不是 file：// ... ）。在HTTP中，将使用HTTP响应头中的字符集。您已将其设置为如下所示：
<％@ page pageEncoding =UTF-8％>
这不仅会使用UTF-8写出HTTP响应，而且会将 charset 属性在 Content-Type 响应标题。
这一个将被网页浏览器用来解释响应和编码任何HTML表单参数。
在$
form 中的$ c> accept-charset 属性：没有任何变化。
它仅在Microsoft Internet Explorer浏览器中有效。即使这样做是错误的。切勿使用它。所有真正的webbrowsers将使用响应的 Content-Type 头中指定的 charset 属性。即使您 not 指定 accept-charset 属性，即使MSIE也会以正确的方式执行此操作。如前所述，您已通过 pageEncoding 正确设置它。
摆脱 meta 标记和 accept-charset 属性。他们没有任何有用的效果，他们只会长期困惑自己，甚至在最终用户使用MSIE时会让事情变得更糟。只需坚持 pageEncoding 。除了在所有JSP页面上重复 pageEncoding ，您还可以在 web.xml 中全局地设置它，如下所示：
< jsp-config>
< jsp-property-group>
< url-pattern> *。jsp< / url-pattern>
< page-encoding> UTF-8< / page-encoding>
< / jsp-property-group>
< / jsp-config>
如上所述，这将告诉JSP引擎使用UTF-8编写HTTP响应输出并设置它也在HTTP响应头中。在发送回服务器之前，webbrowser将使用相同的字符集来编码HTTP请求参数。
你唯一缺少的步骤是告诉服务器在返回 getParameterXxx（）之前必须使用UTF-8解码HTTP请求参数来电。如何做到全局取决于HTTP请求方法。假设您使用的是POST方法，使用下面的servlet过滤器类可以很容易实现，该类会自动挂接所有请求：
@WebFilter（/ *）
public class CharacterEncodingFilter implements Filter {
$ b $ @Override
public void init（FilterConfig config）throws ServletException {
// NOOP。
$ b @Override
public void doFilter（ServletRequest request，ServletResponse response，FilterChain chain）throws IOException，ServletException {
request.setCharacterEncoding（UTF-8 ）;
chain.doFilter（request，response）;
}
@Override
public void destroy（）{
// NOOP。
}
}
就是这样。在Servlet 3.0+（Tomcat 7和更新版本）中，您不需要额外的 web.xml 配置。
您只需要记住在之前首次使用任何方法获取POST请求参数之前， setCharacterEncoding（）方法在之前称为 getParameterXxx（）方法。这是因为它们在首次访问时只被解析一次，然后被缓存在服务器内存中。
字符串foo = request.getParameter（foo）;以下顺序为错误： //错误的编码。
// ...
request.setCharacterEncoding（UTF-8）; //尝试设置它。
String bar = request.getParameter（bar）; //仍然错误的编码！
在a中执行 setCharacterEncoding（）作业servlet过滤器将保证它及时运行（至少在任何servlet之前）。
如果您希望指示服务器使用UTF-8解码GET（而不是POST）请求参数（在URL中的？字符之后看到的那些参数，你知道的），那么你基本上需要在服务器端进行配置。无法通过servlet API进行配置。如果您使用Tomcat作为服务器，则需要在< Connector>中添加 URIEncoding =UTF-8属性。 元素是Tomcat自己的 /conf/server.xml 。
如果您仍然看到 Mojibake
a>在 System.out.println（）调用的控制台输出中，那么很可能stdout本身没有配置为使用UTF-8。如何做到这一点取决于谁负责解释和呈现标准输出。例如，如果您使用Eclipse作为IDE，则需要将另见：
I've visited each one of the questions about UTF-8 encoding in HTML and nothing seems to be making it work like expected.
I added the meta tag : nothing changed.
I added the accept-charset attribute in form : nothing changed.
JSP File
<%@ page pageEncoding="UTF-8" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>Editer les sous-titres</title>
</head>
<body>
<form method="post" action="/Subtitlor/edit" accept-charset="UTF-8">
<h3 name="nameOfFile"><c:out value="${ nameOfFile }"/></h3>
<input type="hidden" name="nameOfFile" id="nameOfFile" value="${ nameOfFile }"/>
<c:if test="${ !saved }">
<input value ="Enregistrer le travail" type="submit" style="position:fixed; top: 10px; right: 10px;" />
</c:if>
<a href="/Subtitlor/" style="position:fixed; top: 50px; right: 10px;">Retour à la page d'accueil</a>
<c:if test="${ saved }">
<div style="position:fixed; top: 90px; right: 10px;">
<c:out value="Travail enregistré dans la base de donnée"/>
</div>
</c:if>
<table border="1">
<c:if test="${ !saved }">
<thead>
<th style="weight:bold">Original Line</th>
<th style="weight:bold">Translation</th>
<th style="weight:bold">Already translated</th>
</thead>
</c:if>
<c:forEach items="${ subtitles }" var="line" varStatus="status">
<tr>
<td style="text-align:right;"><c:out value="${ line }" /></td>
<td><input type="text" name="line${ status.index }" id="line${ status.index }" size="35" /></td>
<td style="text-align:right"><c:out value="${ lines[status.index].content }"/></td>
</tr>
</c:forEach>
</table>
</form>
</body>
</html>
Servlet
for (int i = 0 ; i < 2; i++){
System.out.println(request.getParameter("line"+i));
}
Output
Et ton père et sa soeur
Il ne sera jamais parti.
I added the
metatag : nothing changed.
It indeed doesn't have any effect when the page is served over HTTP instead of e.g. from local disk file system (i.e. the page's URL is http://... instead of e.g. file://...). In HTTP, the charset in HTTP response header will be used. You've already set it as below:
<%@page pageEncoding="UTF-8"%>
This will not only write out the HTTP response using UTF-8, but also set the charset attribute in the Content-Type response header.
This one will be used by the webbrowser to interpret the response and encode any HTML form params.
I added the
accept-charsetattribute inform: nothing changed.
It has only effect in Microsoft Internet Explorer browser. Even then it is doing it wrongly. Never use it. All real webbrowsers will instead use the charset attribute specified in the Content-Type header of the response. Even MSIE will do it the right way as long as you do not specify the accept-charset attribute. As said before, you have already properly set it via pageEncoding.
Get rid of both the meta tag and accept-charset attribute. They do not have any useful effect and they will only confuse yourself in long term and even make things worse when enduser uses MSIE. Just stick to pageEncoding. Instead of repeating the pageEncoding over all JSP pages, you could also set it globally in web.xml as below:
<jsp-config>
<jsp-property-group>
<url-pattern>*.jsp</url-pattern>
<page-encoding>UTF-8</page-encoding>
</jsp-property-group>
</jsp-config>
As said, this will tell the JSP engine to write HTTP response output using UTF-8 and set it in the HTTP response header too. The webbrowser will use the same charset to encode the HTTP request parameters before sending back to server.
Your only missing step is to tell the server that it must use UTF-8 to decode the HTTP request parameters before returning in getParameterXxx() calls. How to do that globally depends on the HTTP request method. Given that you're using POST method, this is relatively easy to achieve with the below servlet filter class which automatically hooks on all requests:
@WebFilter("/*")
public class CharacterEncodingFilter implements Filter {
@Override
public void init(FilterConfig config) throws ServletException {
// NOOP.
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
request.setCharacterEncoding("UTF-8");
chain.doFilter(request, response);
}
@Override
public void destroy() {
// NOOP.
}
}
That's all. In Servlet 3.0+ (Tomcat 7 and newer) you don't need additional web.xml configuration.
You only need to keep in mind that it's very important that setCharacterEncoding() method is called before the POST request parameters are obtained for the first time using any of getParameterXxx() methods. This is because they are parsed only once on first access and then cached in server memory.
So e.g. below sequence is wrong:
String foo = request.getParameter("foo"); // Wrong encoding.
// ...
request.setCharacterEncoding("UTF-8"); // Attempt to set it.
String bar = request.getParameter("bar"); // STILL wrong encoding!
Doing the setCharacterEncoding() job in a servlet filter will guarantee that it runs timely (at least, before any servlet).
In case you'd like to instruct the server to decode GET (not POST) request parameters using UTF-8 too (those parameters you see after ? character in URL, you know), then you'd basically need to configure it in the server end. It's not possible to configure it via servlet API. In case you're using for example Tomcat as server, then it's a matter of adding URIEncoding="UTF-8" attribute in <Connector> element of Tomcat's own /conf/server.xml.
In case you're still seeing Mojibake in the console output of System.out.println() calls, then chances are big that the stdout itself is not configured to use UTF-8. How to do that depends on who's responsible for interpreting and presenting the stdout. In case you're using for example Eclipse as IDE, then it's a matter of setting Window > Preferences > General > Workspace > Text File Encoding to UTF-8.
See also:
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