What is JSP TAG pull? If you know HTML, XML, you should know tag. Any TAG-based language (such as HTML) must be between '<' and '>'. is a title TAG These HTML tags (tags) are usually used for client browsers, which are the format of uniform display data. Similarly, we also use '<' and '>', using them, can do in the server Anything you think. In a subtle difference in JSP and HTML, all JSP tags must follow the syntax of the XML tag, that is, all start tags in JSP (EG ) There must be an ended tag (EG ). In addition, all JSP tags have a prefix, EG 'Star' in tag. Of course, like HTML and XML. , JSP tags also have attributes eg There are two attributes and have been given two values. So, the ready-made label is not used, why should it be self Definition pull-defined benefits: 1. JSP TAG allows Java (server) code and HTML (client) code to separate, this is very important when you are developing a large project, separate the server and client 2.Tags is easy to reuse Java code. 3. You can use a very useful custom Tag library to use it to end customers. 4. Tags is easy to maintain. Oh, you are trying to customize JSP tags. Is it a very easy thing. He is a very easy thing. Just like writing a normal Java class, all we have to do is writing a Java class, then directly execute an interfaces, ---- this is We have to do in this article or expand into a predefined Java class. If you need to overload their methods. So, you will have to write a text tag library descriptor (.tld) Document, make you packaged TAG can be used. Look at our firsttag.java file. Create a new Java program and save in / web-inf / class / com / stardeveloper / tag / test / file ,code show as below:
Package com.stardeveloper.tag.test;
Import java.io. *;
Import javax.servlet.jsp. *;
Import javax.servlet.jsp.tagext. *;
Public class firstttag imports tag, serializable {
Private pageContext PC = NULL;
PRIVATE TAG PARENT = NULL;
Private string name = NULL;
Public void setPageContext (PageContext P) {
PC = P;
}
Public void setparent (tag t) {
Parent = T;
}
Public tag getparent () {
Return Parent;
}
Public void setname (string s) {
Name = s;
}
Public string getname () {
Return Name;
}
Public int desartTartTag () throws jspexception {
Try {
IF (name! = null) {
Pc.getout (). Write ("Hello" Name "!");
} else {
Pc.getOut (). Write ("You Didn't Enter your name"); pc.getout (). Write (", What are you Afraid of?");
}
} catch (ioexception e) {
Throw new jsptagexception ("an ioexception iocurred.");
}
Return Skip_body;
}
PUBLIC INT DOENDTAG () THROWS JSPEXCEPTION {
Return Eval_page;
}
Public void release () {
PC = NULL;
Parent = NULL;
Name = NULL;
}
} Note: Package com.stardeveloper.tag.test; indicates that the firstttag class is packaged and placed in com.stardeveloper.tag.test. 2. Introducing three packages (we use the methods and classes in them) Import java.io . *;
Import javax.servlet.jsp. *;
Import javax.servlet.jsp.tagext. *; Note these two sense interfaces Serializable and Tag, which is not necessary for creating a JSP tags class, and tag is the most important
