问题
I'm new to JSF (just started learning about it 4 days ago) and I'm a bit confused about the usage of h:outputText. I know that is a simple tag, but in most examples I've seen, it's used to output very simple (no need to escape), non-i18n text. For example (taken from here)
<h:outputText value="Transport" />
which could be replaced by
Transport
So, I'm wondering if I'm missing something or if most of the examples I've seen are overcomplicated to the point of insanity.
回答1:
If you're using JSF 2.x with Facelets 2.x instead of JSP, then both are equally valid. Even more, Facelets implicitly wraps inline content in a component as represented by <h:outputText> (in other words, it will be escaped!).
Only whenever you'd like to disable escaping using escape="false", or would like to assign id, style, onclick, etc programmatically, or would like to use a converter (either explicit via converter or implicit via forClass), then you need <h:outputText>.
I myself don't use <h:outputText> whenever it is not necessary. Without it, the source code becomes better readable. You can just inline EL in template text like so #{bean.text} instead of doing <h:outputText value="#{bean.text}">. Before JSF 2.0, in JSP and Facelets 1.x, this was not possible and thus the <h:outputText> is mandatory. If your IDE gives warnings on this, it's most likely JSF 1.x configured/minded.
回答2:
The example you quote is written in XHTML - which is XML. A standalone 'Transport' may not be allowed at the position you want to put it in, so that you need to "transform" it into valid xml.
IIrc this what is called facelets and the default in JSF2, while in JSF1, the presentation code could be done with JSP tags as default and facelets was an alternative that many developers were using).
回答3:
h:outputText tag is required only if you are rendering the text based on some render condition. eg: <h:outputText value="Transport" rendered="#{myBean.displayText}"/>. If its a simple output statement then there is no need of using the tag; you could just use: Transport
来源：https://stackoverflow.com/questions/5539894/is-it-suggested-to-use-houtputtext-for-everything