通用分页（2）

目录

前言

一、pageBean的完善

二、PageTag的实现

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前言

上次我们分享了通用分页（1），今天分享的内容是通用分页（2）。本文的内容基于上一篇文章

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一、pageBean的完善

分析：

 对pagebean进行初始化

初始化jsp页面传递过来的当前页

初始化jsp页面传递过来的页大小

初始化jsp页面传递过来是否分页

保留上一次的查询请求

保留上一次的查询条件

package com.zhw.util;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

public class PageBean {
	private int page = 1;// 页码

	private int rows = 10;// 页大小

	private int total = 0;// 总记录数

	private boolean pagination = true;// 是否分页
	
	private String url;
	
	//保存上一次查询条件
	private Map<String, String[]> parmeterMap = new HashMap<String, String[]>();

	//获取最大页码
	public int maxPage() {
		return this.total % this.rows == 0 ? this.total / this.rows : this.total / this.rows + 1;
	}
	
	//获取上一页的页码
	public int previousPage() {
		return this.page > 1 ? this.page -1 : this.page;
	}
	
	//获取下一页的页码
	public int nextPage() {
		return this.page<this.maxPage() ? this.page +1 : this.page;
	}
	
	//初始化pagebean
	public void setRequest(HttpServletRequest req) {
		this.setPage(req.getParameter("page"));
		this.setRows(req.getParameter("rows"));
		this.setPagination(req.getParameter("pagination"));
		this.setUrl(req.getRequestURL().toString());
		this.setParmeterMap(req.getParameterMap());
	}
	private void setPage(String page) {
		if(StringUtils.isNotBlank(page)) {
			//set自动生成的方法
			this.setPage(Integer.valueOf(page));
		}
		
	}
	
	private void setPagination(String pagination) {
		if(StringUtils.isNotBlank(pagination)) {
			this.setPagination(!"false".equals(pagination));
		}
	}
	
	private void setRows(String rows) {
		if(StringUtils.isNotBlank(rows)) {
			this.setRows(Integer.valueOf(rows));
		}
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public Map<String, String[]> getParmeterMap() {
		return parmeterMap;
	}

	public void setParmeterMap(Map<String, String[]> parmeterMap) {
		this.parmeterMap = parmeterMap;
	}

	public PageBean() {
		super();
	}

	public int getPage() {
		return page;
	}

	public void setPage(int page) {
		this.page = page;
	}

	public int getRows() {
		return rows;
	}

	public void setRows(int rows) {
		this.rows = rows;
	}

	public int getTotal() {
		return total;
	}

	public void setTotal(int total) {
		this.total = total;
	}

	public void setTotal(String total) {
		this.total = Integer.parseInt(total);
	}

	public boolean isPagination() {
		return pagination;
	}

	public void setPagination(boolean pagination) {
		this.pagination = pagination;
	}

	/**
	 * 获得起始记录的下标
	 * 
	 * @return
	 */
	public int getStartIndex() {
		return (this.page - 1) * this.rows;
	}

	@Override
	public String toString() {
		return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination
				+ ", url=" + url + ", parmeterMap=" + parmeterMap + "]";
	}

}

二、PageTag的实现

package com.zhw.tag;

import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

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

import com.zhw.util.PageBean;

public class PageTag extends BodyTagSupport{
	private PageBean pagebean;
	
	
	
	public PageBean getPagebean() {
		return pagebean;
	}

	public void setPagebean(PageBean pagebean) {
		this.pagebean = pagebean;
	}

	@Override
	public int doStartTag() throws JspException {
		JspWriter out = pageContext.getOut();
		try {
			out.print(toHTML());
		} catch (Exception e) {
			e.printStackTrace();
		}
		return super.doStartTag();
	}

	private Object toHTML() {
		StringBuffer sb = new StringBuffer();
		
		sb.append("<form action='"+pagebean.getUrl()+"' id='pageBeanForm' method='post'>");
		sb.append("	<input type='hidden' name='page'>");
		Map<String, String[]> parmeterMap = pagebean.getParameterMap();
		if(parmeterMap != null && parmeterMap.size()>0) {
			Set<Entry<String, String[]>> entrySet = parmeterMap.entrySet();
			for (Entry<String, String[]> entry : entrySet) {
				String key = entry.getKey();
				String[] value = entry.getValue();
				if(!"page".equals(key)) {
					for (String string : value) {
						sb.append("	<input type='hidden' name='"+key+"' value='"+value+"'>");
					}
				}
			}
		}
		sb.append("</form>");
		sb.append("<ul class='pagination justify-content-center'>");
		sb.append(" <li class='page-item'><a class='page-link'");
		sb.append("     href='javascript:gotoPage(1)'>首页</a></li>");
		sb.append("	<li class='page-item'><a class='page-link'");
		sb.append("		href='javascript:gotoPage("+pagebean.previousPage()+")'>&lt;</a></li>");
		sb.append("	<li class='page-item'><a class='page-link' href='#'>"+pagebean.getPage()+"</a></li>");
		sb.append(" <li class='page-item "+(pagebean.getPage() == pagebean.maxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pagebean.nextPage()+")'>&gt;</a></li>");
		sb.append("	<li class='page-item "+(pagebean.getPage() == pagebean.maxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pagebean.maxPage()+")'>尾页</a></li>");
		sb.append("	<li class='page-item go-input'><b>到第</b><input class='page-link'");
		sb.append("		type='text' id='skipPage' name='' /><b>页</b></li>");
		sb.append("	<li class='page-item go'><a class='page-link'");
		sb.append("		href='javascript:skipPage()'>确定</a></li>");
		sb.append("	<li class='page-item'><b>共"+pagebean.getTotal()+"条</b></li>");
		sb.append("</ul>");
		sb.append("<script type='text/javascript'>");
		sb.append("	function gotoPage(page) {");
		sb.append("		document.getElementById('pageBeanForm').page.value = page;");
		sb.append("		document.getElementById('pageBeanForm').submit();");
		sb.append("	}");
		sb.append("	function skipPage() {");
		sb.append("		var page = document.getElementById('skipPage').value;");
		sb.append("		if (!page || isNaN(page) || parseInt(page) < 1");
		sb.append("				|| parseInt(page) > "+pagebean.maxPage()+") {");
		sb.append("			alert('请输入1~"+pagebean.maxPage()+"的数字');");
		sb.append("			return;");
		sb.append("		}");
		sb.append("		gotoPage(page);");
		sb.append("	}");
		sb.append("</script>");
		
		return sb;
	}
}

Servlet：

package com.zhw.web;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.zhw.dao.BookDao;
import com.zhw.entity.Book;
import com.zhw.util.PageBean;

@WebServlet("/book/search")
public class BookServlet extends HttpServlet{
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		BookDao bookDao = new BookDao();
		PageBean pageBean = new PageBean();
		pageBean.setRequest(req);
		Book book = new Book();
		book.setBname(req.getParameter("bname"));
		try {
			List<Book> list = bookDao.list(book , pageBean);
			req.setAttribute("books", list);
			req.setAttribute("pageBean", pageBean);
			req.getRequestDispatcher("/bookList.jsp").forward(req, resp);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

 

 

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