parametertag.java

OA典型例子

/*
    * $Id: ParameterTag.java,v 1.6 2001/10/26 22:55:55 ro89390 Exp $
    * Copyright 2000 Sun Microsystems, Inc. All rights reserved.
    * Copyright 2000 Sun Microsystems, Inc. Tous droits r?erv?.
    */

package com.sure.taglibs.request;

import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.tagext.TagSupport;

/**
  *
  * This class allows you to retrieve a parameter from
  * the request and output it to the page  This should allow
  * you to avoid expressions for extracting parameter info.
  *
  */
public class ParameterTag extends TagSupport {

    private String parameter = null;
    private String defaultValue = "";
    private boolean asURL;

    public ParameterTag() {
        super();
    }

    public void setName(String p) { parameter = p; }

    public void setDefault(String d) { defaultValue = d; }

    public int doStartTag() throws JspTagException {
        return SKIP_BODY;
    }

    public int doEndTag() throws JspTagException {
        String outputText = "";
        try {
            if (parameter != null) {
                outputText = pageContext.getRequest().getParameter(parameter);
                if (outputText != null) {
                    pageContext.getOut().print(outputText);
                }
                else {
                    pageContext.getOut().print(defaultValue);
                }
            }
            else {
                pageContext.getOut().print(defaultValue);
            }
        } catch (Exception ex) {
            System.err.println("Parameter Tag:doEndTag caught: " + ex);
        }       return EVAL_PAGE;
    }
}