fenyetag.java

通用分页标签,对学习自定义标签的同志学习有一定意义

package fy;

import javax.servlet.jsp.tagext.BodyTagSupport;
import javax.servlet.jsp.*;


public class FenYeTag extends BodyTagSupport {

	private String url = null;//当前页面的URL
	private int pageCount = 0;//总页数
	//private int countPerPage;//每页显示的行数
	
	public void setUrl(String currentURL) {
		
		this.url = currentURL;
	}
	
	public void setPageCount(int count) {
		
		this.pageCount = count;
	}
	
	/*public void setCountPerPage(int perPage) {
		
		this.countPerPage = perPage;
	}*/
	
	public int doStartTag() throws JspTagException, JspException {
		
		String strCurPage = this.pageContext.getRequest().getParameter("page");//得到当前页的页数
		int curPage = 0;//用来存取当前页		
		
		if (strCurPage == null) {
			
			curPage = 1;
		}else {
			
			curPage = Integer.parseInt(strCurPage);//得到当前页的页数
		}		
		StringBuffer sb = null;
		if (this.pageCount != 0 && curPage != 0) {
			
			sb = new StringBuffer("分页  ");
			if (curPage == 1) {
				sb.append("首页||上一页||");
			}else {
				//首页的链接
				sb.append("<a href='").append(this.url).append("?page=1'>");
				sb.append("首页").append("</a>").append("||");
				//上一页的链接
				sb.append("<a href='").append(this.url).append("?page=").append(curPage-1).append("'>");
				sb.append("上一页").append("</a>").append("||");
			}
			
			if (curPage == this.pageCount) {
				sb.append("后一页||尾页");
			}else {
				//后一页的链接
				sb.append("<a href='").append(this.url).append("?page=").append(curPage+1).append("'>");
				sb.append("后一页").append("</a>").append("||");
				//尾页的链接
				sb.append("<a href='").append(this.url).append("?page=").append(this.pageCount).append("'>");
				sb.append("尾页").append("</a>");
			}			
		}
		
		//跳转到多少页
		sb.append("&nbsp;&nbsp;跳转到:<select name='goToPage' onchange='javascript:goPage(this.value)'>");
		String p = pageContext.getRequest().getParameter("page");
		int j = 1;
		if (p != null) {
			j = Integer.parseInt(p);
		}
		for (int i = 1;i <= this.pageCount;i++) {
			
			sb.append("<option value=").append(i);
			if (i == j) {
				sb.append(" selected");
			}
			sb.append(">第").append(i).append("页</option>");
		}
		
		
		sb.append("</select>");
	
		
		//定义goPage函数
		sb.append("<script language='javascript'>");
		sb.append("function goPage(willpage) {");
		sb.append("window.location='").append(this.url).append("?page='+").append("willpage");
		sb.append("}").append("</script>");
		
		//System.out.println(sb.toString());		
		JspWriter out = this.pageContext.getOut();
		try {
			out.print(sb.toString());
		}catch (Exception e) {
			throw new JspException(e);
		}
		return EVAL_PAGE;
	}
}