3.3.3 other useful presentation tags

还有一些用来创建view的tags，请参见它们的文档。 ·   [logic] iterate repeats its tag body once for each element of a specified collection (which can be an enumeration, a hashtable, a vector, or an array of objects). ·   [logic] present depending on which attribute is specified, this tag checks the current request, and evaluates the nested body content of this tag only if the specified value is present. only one of the attributes may be used in one occurrence of this tag, unless you use the property attribute, in which case the name attribute is also required. the attributes include cookie, header, name, parameter, property, role, scope, and user. ·   [logic] notpresent the companion tag to present, notpresent provides the same functionality when the specified attribute is not present. ·   [html] link generates a html <a> element as an anchor definition or a hyperlink to the specified url, and automatically applies url encoding to maintain session state in the absence of cookie support. ·   [html] img generates a html <img> element with the ability to dynamically modify the urls specified by the "src" and "lowsrc" attributes in the same manner that <html:link> can. ·   [bean] parameter retrieves the value of the specified request parameter, and defines the result as a page scope attribute of type string or string[].