tokentag.java

一个实用工具类

/*
 * Copyright (C) butor.com. All rights reserved.
 *
 * This software is published under the terms of the GNU Library General
 * Public License (GNU LGPL), a copy of which has been included with this
 * distribution in the LICENSE.txt file. 
 */


package org.butor.web.taglib.html;

import java.io.IOException;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

import org.apache.struts.action.Action;
import org.butor.log.Log;
import org.butor.web.Constants;
import org.butor.web.context.IWebContext;
import org.butor.web.context.WebContextService;


/**
 * Put token in form to be submitted and checked by an intereseted action.
 * 
 * @author Aiman SAWAN
 */
public class TokenTag extends TagSupport {
	
	/**
	 * @see Tag#doStartTag()
	 */
	public int doStartTag() throws JspException {
		IWebContext context = WebContextService.getContext();
		if (context == null){
			Log.logStr(this, Log.LOG_TYPE_ERROR, "doStartTag()", "Got null context!");
			return EVAL_PAGE;
		}	

		JspWriter writer = pageContext.getOut();
		if (writer == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "doStartTag()", 
				"Got null JspWriter!");
			return EVAL_PAGE;
		}
		
        try {
            writer.print("<input type=\"hidden\" name=\"");
            writer.print(Constants.TOKEN);
            writer.print("\" value=\"");
            writer.print(context.readProperty(Constants.TOKEN));
            writer.println("\"/>");
            
        } catch (IOException e) {
            throw new JspException(e.toString());
        }				
		
		return EVAL_PAGE;
	}
}