numberformtag.java

一个用struts tiles的在线影院web系统

package com.eline.common.taglib;

import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

import com.blue.web.common.util.AppLogger;

/**
 * 显示指定页数
 * @author Lucifer
 * @version 1.0
 */

public class NumberFormTag extends TagSupport {

	private static final long serialVersionUID = -4413167264546532053L;

	private String action = null;
	private ListTag listTag = null;
	private int goPage = 0; //所转到的页数

	/**
	 * 
	 * @throws JspException
	 */
	public int doEndTag() throws JspException {
		try {
			JspWriter out = pageContext.getOut();
			out.print("</form>");
		} catch (IOException ex) {
			AppLogger.error("NumberFormTag.doEndTag(): 产生转到指定页标记错误!");
		}

		return EVAL_PAGE;
	}

	/**
	 * 
	 * @throws JspException
	 */
	public int doStartTag() throws JspException {
		//验证其必须在列表标记内
		listTag = (ListTag) findAncestorWithClass(this, ListTag.class);
		if (listTag == null) {
			throw new JspTagException("转到指定页标记不在列表标记内!");
		}

		HttpServletRequest request = (HttpServletRequest) pageContext.getRequest();

		if (request.getParameter(listTag.getParamPrefix() + "goPage")!=null && !request.getParameter(listTag.getParamPrefix() + "goPage").equals(""))
			goPage = Integer.parseInt(request.getParameter(listTag.getParamPrefix() + "goPage").trim());
		else
			goPage = 1;

		if (goPage < 1)	//如果小于第一页则取其为第一页
			goPage = 1;
		else if (goPage > listTag.totalPages)	//若大于最后一页则取最后一页
			goPage = listTag.totalPages;
		
		try {
			JspWriter out = pageContext.getOut();
			out.println("<form method=\"" + request.getMethod() + "\" action=\"" + action + "\">");
			out.println("	<input type=\"hidden\" name=\"" + listTag.getParamPrefix() + listTag.getPageIndexParam() + "\" value=\"" + (goPage-1) + "\" />");
            out.println("	<input type=\"hidden\" name=\"" + listTag.getParamPrefix() + listTag.getPrevParam() + "\" value=\"true\" />");
            out.println("	<input type=\"text\" name=\"" + listTag.getParamPrefix() + "goPage\" value=\"" + goPage + "\" />");
		} catch (IOException e) {
			AppLogger.error("NumberFormTag.doStartTag() : 产生转到指定页标记错误!");
		}
		
		return EVAL_BODY_INCLUDE;
	}

	public void setAction(String action) {
		this.action = action;
    }
}