JSP (8)--jsp Tags

JS JSP Another important syntax is tags (tags). JSP tags are not the use of <%, but only the use of characters. JSP tag is a bit like HTML tag. JSP tags can have a "start tag", a "tag body" and an "end tag." Both the beginning and the end of the logo can be used with the name of the flag, all of which are circled in the "and" characters. The end sign is to add a backslash (/) character after the character. The name of the sign has an embedded colon (:) character in it, where the section before the colon describes the type of the flag. Let's take an example:

＜some:tag＞

body

＜/some:tag＞

If the flag does not require a body, the start and end flags can be combined, such as:

＜some:tag/＞

Here we use a/> instead of the > character so that we can quickly end the flag without needing an entity. This syntax is the same as the XML one.

Flags can be divided into two types: one is reproduced from an external tag library, and the other is a predefined logo. The predefined flags start with the JSP: character. For example, Jsp:include is a predefined logo used to include other web pages.

In the previous tutorial we have learned "include directive". In fact, it is very similar to jsp:include. Instead of loading the text of the contained files in the original file, they invoke the included flags at run time. Here is an example of a jsp:include use:

＜HTML＞

＜BODY＞

Going to include hello.jsp...＜BR＞

＜jsp:include page="hello.jsp"/＞

＜/BODY＞

＜/HTML＞

Now change the "Jsp:include" in the above code to "Jsp:forward" to see what the difference is. In fact, these two predefined flags are very useful.

Give the practice in this section and write a JSP that will be based on a Boolean (Boolean) variable to a contained file. Here is a hint, to use HTML and scriptlets mixed programming to handle JSP flags.