如何仅将特殊字符转换为 html 实体而不转义 <、>、" 和 '？

Question

I need to escape special characters in mail to html5 entities, because, even if the mail is sent as utf8, some client mails does not display them correctly. I don't want to use entities directly in the mail, since the mail are made by testers and we don't want to enforce testers to learn all html5 entities.

I tried to use

org.unbescape.html.HtmlEscape.escapeHtml​(
    string, 
    HtmlEscapeType.HTML5_NAMED_REFERENCES_DEFAULT_TO_DECIMAL,
    HtmlEscapeLevel.LEVEL_2_ALL_NON_ASCII_PLUS_MARKUP_SIGNIFICANT
)

link

but they both escape also < , > , " and ' characters.

Now I'm using this self-made method:

public static final String encodeHTML(final String s) {
    String res = HtmlEscape.escapeHtml(
        s, 
        HtmlEscapeType.HTML5_NAMED_REFERENCES_DEFAULT_TO_DECIMAL,
        HtmlEscapeLevel.LEVEL_2_ALL_NON_ASCII_PLUS_MARKUP_SIGNIFICANT
    );

    res = res.replaceAll("&lt;", "<");
    res = res.replaceAll("&gt;", ">");
    res = res.replaceAll("&quot;", "\"");
    res = res.replaceAll("&apos;", "'");
    res = res.replaceAll("&amp;", "&");

    return res;
}

Example:

encodeHTML("<div id='a' class\"ciao\">&amp; ®</div>")

outputs:

<div id='a' class"ciao">&amp; &reg;</div>

That's what I want, but there's not something more standard?

Answer 1

Following code help you to convert only special characters.

import org.apache.commons.text.StringEscapeUtils;
import org.apache.commons.text.translate.AggregateTranslator;
import org.apache.commons.text.translate.EntityArrays;
import org.apache.commons.text.translate.LookupTranslator;

public String encodeHTML(String s) {

    StringEscapeUtils.Builder buider =StringEscapeUtils
        .builder(new AggregateTranslator(new LookupTranslator(EntityArrays.ISO8859_1_ESCAPE),
            new LookupTranslator(EntityArrays.HTML40_EXTENDED_ESCAPE)));

    return buider.escape(s).toString();
  }