JSF ID的规则是什么? [英] What are the rules for a JSF id?

问题描述

似乎我应该可以在半个小时的网上搜索中找到它，但是由于我不能:

It seems like I should be able to find this with a half hour of searching the webs, but since I cannot:

有效的JSF ID有哪些规则?

我读到一封乱码的电子邮件，提示-和_受到限制，但是我收到了IllegalArgumentExceptions，我认为这是由于ID造成的.

I read a garbled e-mail message that suggested there were limitations on - and _, but I'm getting IllegalArgumentExceptions and I think it's due to the ids.

编辑

java.lang.IllegalArgumentException: 6a945017207d46fd82b3d3bb7d2795f1
at javax.faces.component.UIComponentBase.validateId(UIComponentBase.java:549)
at javax.faces.component.UIComponentBase.setId(UIComponentBase.java:351)
at com.sun.facelets.tag.jsf.ComponentHandler.apply(ComponentHandler.java:151)

推荐答案

必须为有效的 CSS标识符(ident 此处)，并且不应重复.

It has to be a valid CSS identifier (the ident here) and there should be no duplicates.

在CSS中，选择器中的标识符(包括元素名称，类和ID )只能包含字符[a-zA-Z0-9]和ISO 10646字符U+00A1及更高版本，以及连字符(-)和下划线(_)；它们不能以数字开头，也不能以连字符后接数字开头.标识符还可以包含转义字符和任何ISO 10646字符作为数字代码(请参阅下一项).例如，标识符"B&W?"可以写为"B\&W\?"或"B\26 W\3F".

In CSS, identifiers (including element names, classes, and IDs in selectors) can contain only the characters [a-zA-Z0-9] and ISO 10646 characters U+00A1 and higher, plus the hyphen (-) and the underscore (_); they cannot start with a digit, or a hyphen followed by a digit. Identifiers can also contain escaped characters and any ISO 10646 character as a numeric code (see next item). For instance, the identifier "B&W?" may be written as "B\&W\?" or "B\26 W\3F".

另请参见:

• CSS标识符允许使用字符

See also:

• Allowed characters for CSS identifiers

更新:对于您感兴趣的情况，这是由UIComponentBase#validateId()提供的验证器的源代码:

Update: for the case you're interested, here's the source code of the validator as provided by UIComponentBase#validateId():

private static void validateId(String id) {
    if (id == null) {
        return;
    }
    int n = id.length();
    if (n < 1) {
        throw new IllegalArgumentException("Empty id attribute is not allowed");
    }
    for (int i = 0; i < n; i++) {
        char c = id.charAt(i);
        if (i == 0) {
            if (!Character.isLetter(c) && (c != '_')) {
                throw new IllegalArgumentException(id);
            }
        } else {
            if (!Character.isLetter(c) &&
                    !Character.isDigit(c) &&
                    (c != '-') && (c != '_')) {
                throw new IllegalArgumentException(id);
            }
        }
    }
}

但是，它比CSS规则要严格一些.它们也不能以连字符开头.

It's however a little more strict than the CSS rules. They cannot start with a hyphen as well.

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