JSP Custom Label (3) __jsp

Eight, Simpletagsupport class

After JSP2.0, in order to simplify the difficulty of label development, you can use simpletagsupport for development;

1. Developing generic labels

Note the point:

(1) need to inherit Simpletagsupport class;

(2) Realizing the public void Dotag() throws jspexception,ioexception;

(3) Super. Getjspcontext (). getout (). Write   ("...."); for output;

(4) in Simpletagsupport, the <body-content> content in TLD can not be JSP, if the label body is not empty, it can only be scriptless;

Code:

Simpletagsupportdemo.java

Package org.tagext;
Import javax.servlet.jsp.tagext.*;
Import javax.servlet.jsp.*;
Import java.io.*;
public class Simpletagsupportdemo extends simpletagsupport{
	private String name;
	Public String GetName () {return
		name;
	}
	public void SetName (String name) {
		this.name = name;
	}
	public void Dotag () throws jspexception,ioexception{
		Super.getjspcontext (). Getout (). Write ("
 


2. Development of iterative labels
Through Super.getjspbody (). Invoke (null); Can execute tag body content;
Simpletagsupportdemo.java

Package org.tagext;
Import javax.servlet.jsp.tagext.*;
Import javax.servlet.jsp.*;
Import java.io.*;
Import java.util.*;
public class Simpletagsupportdemo extends simpletagsupport{
	private String name;
	Private String ID;
	Public String GetName () {return
		name;
	}
	public void SetName (String name) {
		this.name = name;
	}
	Public String GetId () {return
		ID;
	}
	public void SetId (String id) {
				this.id = ID;
	}
	public void Dotag () throws jspexception,ioexception{
		Object value = Super.getjspcontext (). getattribute (Name, Pagecontext.page_scope);
		Iterator<string> iter = ((list<string>) value). iterator ();
		while (Iter.hasnext ()) {
			super.getjspcontext (). setattribute (Id,iter.next ());
			Super.getjspbody (). Invoke (null);}}}
 

In general, Simpletagsupport is much simpler than the previous tagsupport,bodytagsupport and does not require any return value;

 

 
ix. FAQ 

 
1. Distinguish whether there is a label body

<xiazdong:hello name= "" >

</xiazdong:hello>

It belongs to the label body, but the label body is empty;

<xiazdong:hello name= ""/> is empty for the label body;