Professional Java Server Programming J2EE Edition
Chapter 12
Attributes can be either required or optional. This is specified in the TLD, as is whether attributes can take
the value of JSP expressions at runtime, as we mentioned earlier.
Let's suppose we decide to pass a name as an attribute, and change our simple example to display the following:
First, we need to write a tag handler with a name property. With this minor change, it's pretty much like
HelloTag:
package tagext;
import java.io.IOException;
import java.util.Date;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
// Hello tag accepting a name attribute.
public class AttribHelloTag extends TagSupport
{
private String name;
// Property getter for name
public String getName() {
return name;
}
// Property setter for name
public void setName(String name) {
this.name = name;
}
public int doEndTag() throws JspTagException {
String dateString = new Date().toString();
try {
pageContext.getOut().write("Hello <b>" + name + "</b>.<br/>");
pageContext.getOut().write("My name is " + getClass().getName() +
" and it's " + dateString + "<p/>");
}
catch (IOException ex) {
throw new JspTagException("Hello tag could not write to JSP out");
}
return EVAL_PAGE;
}
}
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