通用分页02

一、分页前台

二、封装界面代码

一、分页前台

1、分析

需要新增变量保存上一次请求地址

需要新增变量保存上一次查询条件

需要添加方法，获取最大页码

需要添加方法，获取上一页的页码

需要添加方法，获取下一页的页码

需要添加方法，初始化pagebean

2、重写·PageBean

package com.yzq.util;

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

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
	
	//需要新增变量保存上一次请求地址
	private String url;
	//需要新增变量保存上一次查询条件
	private Map parameterMap = new HashMap();
	//需要添加方法，获取最大页码
	public int maxPage() {
		return this.total % this.rows == 0 ? this.total / this.rows : this.total / this.rows+1;
	}
	//需要添加方法，获取上一页的页码
	public int previousPage() {
		return this.page > 1 ? this.page-1 : this.page;
	}
	//需要添加方法，获取下一页的页码
	public int nextPage() {
		return this.page < this.maxPage() ? this.page+1 : this.page;
	}
	//需要添加方法，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.getRequestURI().toString());
		this.setParameterMap(req.getParameterMap());
	}

	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));
		}
	}
	private void setPage(String page) {
		if(StringUtils.isNotBlank(page))
		//set自动生成的方法
			this.setPage(Integer.valueOf(page));
		
	}
	public String getUrl() {
		return url;
	}

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

	public Map getParameterMap() {
		return parameterMap;
	}

	public void setParameterMap(Map parameterMap) {
		this.parameterMap = parameterMap;
	}

	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;
	}

	
	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 + ", parameterMap=" + parameterMap + "]";
	}
	
}

3、servlet测试

package com.yzq.web;

import java.io.IOException;
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.yzq.util.PageBean;

@WebServlet("/book/searc")
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 {	
		PageBean pageBean = new PageBean();
		pageBean.setRequest(req);
	
		req.setAttribute("pagebean", pageBean);
		req.getRequestDispatcher("/bookList.jsp").forward(req, resp);
	}
}

bookList.jsp界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>




Insert title here


${pagebean }

运行如下

二、封装界面代码

1、助手类

package com.yzq.tag;

import java.io.IOException;
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.yzq.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 (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return super.doStartTag();
	}

	private String toHTML() {
		StringBuffer sb = new StringBuffer();
		//隐藏的form表单，作用保存上一次查询条件
		sb.append("");
		sb.append(" ");
		Map parameterMap = pageBean.getParameterMap();
		if(parameterMap !=null &¶meterMap.size()>0) {
			Set> entrySet = parameterMap.entrySet();
			for (Entry entry : entrySet) {
				String key = entry.getKey();
				String[] values = entry.getValue();
				if(!"page".equals(key)) {
					for (String value : values) {
						sb.append("");
					}
				}
			}
		}
		sb.append("");
		//分页条
		sb.append("");
		sb.append(" 首页");
		sb.append(" <");
		sb.append(" "+pageBean.getPage()+"");
		sb.append(" >");
		sb.append(" 尾页");
		sb.append(" 到第页");
		sb.append(" 确定");
		sb.append(" 共"+pageBean.getTotal()+"条");
		sb.append("");
		//分页js代码
		sb.append("");
		return sb.toString();
	}
}

界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
	<%@ taglib uri="http://jsp.yzq.wf" prefix="y" %>
	<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>






书籍列表



	
		
			
		
		
	

	
			
		
			
				书籍ID
				书籍名
				价格
			
		
		
			
				${b.bid }
				${b.bname }
				${b.price }

书籍ID	书籍名	价格
${b.bid }	${b.bname }	${b.price }

servlet

package com.yzq.web;

import java.io.IOException;
import java.sql.SQLException;
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.yzq.dao.BookDao;
import com.yzq.entity.Book;
import com.yzq.util.PageBean;

@WebServlet("/book/searc")
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 {	
		PageBean pageBean = new PageBean();
		pageBean.setRequest(req);
		BookDao bd = new BookDao();
		Book book = new Book();
		book.setBname(req.getParameter("bname"));
		try {
			List books = bd.list2(book, pageBean);
			req.setAttribute("books", books);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	
		req.setAttribute("pagebean", pageBean);
		req.getRequestDispatcher("/bookList.jsp").forward(req, resp);
	}
}

通用分页02

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