servlet是否知道使用http-equiv指定的发送表单的编码？ [英] Does a servlet know the encoding of the sent form that specified using http-equiv?
问题描述
servlet是否知道使用http-equiv指定的发送表单的编码？
Does a servlet knows the encoding of the sent form that specified using http-equiv?
当我使用http-equiv指定POSTed表单的编码时：
When I specify an encoding of a POSTed form using http-equiv like that:
<HTML>
<head>
<meta http-equiv='Content-Type' content='text/html; charset=gb2312'/>
</head>
<BODY >
<form name="form" method="post" >
<input type="text" name="v_rcvname" value="相宜本草">
</form>
</BODY>
</HTML>
然后在servlet我使用方法， request.getCharacterEncoding（） 我得到 null ！
那么有没有办法告诉服务器我在一些char编码中编码数据？
And then at the servlet I use the method, request.getCharacterEncoding() I got null !
So, Is there a way that I can tell the server that I am encoding the data in some char encoding??
推荐答案
这将确实从大多数webbrowsers返回 null 。但是通常你可以放心地假设web浏览器实际上使用原始响应头中指定的编码，这在这种情况下是 gb2312 。一个常见的方法是创建一个 Filter ，它检查请求编码，然后使用 ServletRequest＃setCharacterEncoding（） 强制所需的值（您当然应该在整个Web应用程序中始终使用）。
This will indeed return null from most webbrowsers. But usually you can safely assume that the webbrowser has actually used the encoding as specified in the original response header, which is in this case gb2312. A common approach is to create a Filter which checks the request encoding and then uses ServletRequest#setCharacterEncoding() to force the desired value (which you should of course use consistently throughout your webapplication).
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
if (request.getCharacterEncoding() == null) {
request.setCharacterEncoding("gb2312");
}
chain.doFilter(request, response);
}
映射这个过滤器在 url-pattern 上覆盖所有servlet请求，例如 / * 。
Map this Filter on an url-pattern covering all servlet requests, e.g. /*.
如果你没有这样做，让它走，那么servletcontainer将使用它的默认编码来解析参数，通常是 ISO-8859-1 ，而这又是错误的。您输入的相宜本草最终会像ÏàÒ˱¾²Ý。
If you didn't do this and let it go, then the servletcontainer will use its default encoding to parse the parameters, which is usually ISO-8859-1, which in turn is wrong. Your input of 相宜本草 would end up like ÏàÒ˱¾²Ý.
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