文章目录

• 1、需要的资源
• 2、分页的实现

1、需要的资源

DBAccess类：提供了一组获得或关闭数据库对象的方法
config.properties：连接数据库
EncodingFiter类：中文乱码处理
StringUtils类：判断是否存在
Book类：它是一个实体类
PageTag类 ：自定义标签的助手类
BookDao类 ：所用到的dao方法
PageBean类 ：分页的工具类【核心类】

2、分页的实现

分页工具类【核心代码】PageBean类

package com.zyp.util;import java.util.HashMap;
import java.util.Map;import javax.servlet.http.HttpServletRequest;/*** 分页工具类**/
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;private Map<String, String[]> paramMap = new HashMap<>();public void setRequest(HttpServletRequest req) {this.setPage(req.getParameter("page"));this.setRows(req.getParameter("rows"));this.setPagination(req.getParameter("pagination"));// getRequestURL获取到浏览器请求的全路径this.setUrl(req.getRequestURL().toString());// getParameterMap可以获取到一次url请求所携带的所有参数this.setParamMap(req.getParameterMap());}public void setPagination(String pagination) {if (StringUtils.isNotBlank(pagination)) {this.setPagination(!"false".equals(pagination));//是否分页}}public void setRows(String rows) {if (StringUtils.isNotBlank(rows))this.setRows(Integer.valueOf(rows));//每页多少天数据}public void setPage(String page) {if (StringUtils.isNotBlank(page)) {this.setPage(Integer.valueOf(page));//多少页}}public PageBean() {super();}public String getUrl() {return url;}public void setUrl(String url) {this.url = url;}public Map<String, String[]> getParamMap() {return paramMap;}public void setParamMap(Map<String, String[]> paramMap) {this.paramMap = paramMap;}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;}@Overridepublic String toString() {return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + "]";}/*** 获取到总页数* @return*/public int getMaxPage() {return this.total % this.rows == 0 ? this.total / this.rows : (this.total / this.rows) + 1;}/*** 获取下一页页码* @return*/public int getNextPage() {return this.page < this.getMaxPage() ? this.page+1 : this.page;}/*** 获取上一页页码* @return*/public int getPreviousPage() {return this.page > 1 ? this.page-1 : this.page;}}

PageTag类

package com.zyp.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.zyp.util.PageBean;public class PageTag extends BodyTagSupport{private static final long serialVersionUID = -3609493782238830873L;private PageBean pageBean;@Overridepublic int doStartTag() throws JspException {JspWriter out = pageContext.getOut();try {out.write(toHTML());} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}return super.doStartTag();}public String toHTML() {StringBuffer sb = new StringBuffer();//下一次请求提交到后台的表单html代码拼接sb.append("
");Map<String, String[]> paramMap = pageBean.getParamMap();if(paramMap !=null && paramMap.size()>0) {Set<Entry<String, String[]>> entrySet = paramMap.entrySet();for(Entry<String, String[]> entry:paramMap.entrySet()) {if(!"page".equals(entry.getKey())) {sb.append("");}}}sb.append("");sb.append(""
);//分页条html代码拼接sb.append("");sb.append("每页"+pageBean.getRows()+"条，共"+pageBean.getTotal()+"条，第"+pageBean.getPage()+"页，共"+pageBean.getMaxPage()+"页  +pageBean.getPreviousPage()+")'>首页  上一页  +pageBean.getNextPage()+")'>下一页  +pageBean.getMaxPage()+")'>尾页  );sb.append(" id='skipPage'");sb.append(" style='text-align: center; font-size: 12px; width: 50px;'>  Go");sb.append("");//分页所需要调用的js代码sb.append("");return sb.toString();}public PageBean getPageBean() {return pageBean;}public void setPageBean(PageBean pageBean) {this.pageBean = pageBean;}}

BookServlet类

package com.zyp.web;import java.io.IOException;
import java.sql.SQLException;
import java.util.List;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import com.zyp.dao.BookDao;
import com.zyp.entity.Book;
import com.zyp.util.PageBean;public class BookServlet extends HttpServlet{
//	调用数据层访问数据库private BookDao bookDao = new BookDao();private static final long serialVersionUID = -7654671804738498584L;@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//		拿到前台的dnameString bname = req.getParameter("bname");
//		将前台传过来的值封装到实体类中Book book = new Book();//把bname放进去book.setBname(bname);//有可能查询维度不止这个bname，有可能还会有别的。这里的话以bname为例PageBean pagebean = new PageBean();try {
//			list 查出符合条件的某一页的记录数 默认是第一页List<Book> list = bookDao.list(book, pagebean);
//			转发的同时转到req的作用域中req.setAttribute("bookList", list);req.setAttribute("pagebean", pagebean);//pagebean传过去了，最大页数，当前页数，是否分页，第几页都传过去了。req.getRequestDispatcher("bookList.jsp").forward(req, resp);//转发} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}}
}

z.tld属性文件

<?xml version="1.0" encoding="UTF-8" ?><taglib xmlns="http://java.sun.com/xml/ns/j2ee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"version="2.0"><description>zking 1.1 core library</description><display-name>zking core</display-name><tlib-version>1.1</tlib-version><short-name>c</short-name><uri>/zking</uri><tag><!-- 标签库中的标签名 --><name>page</name><!-- 标签对应的助手类的全路径名 --><tag-class>com.zking.tags.PageTag</tag-class><!-- JSP --><body-content>JSP</body-content><attribute><!-- 属性名 --><name>pageBean</name><!-- 属性值是否必填 --><required>true</required><!-- 是否支持表达式 --><rtexprvalue>true</rtexprvalue></attribute></tag></taglib>

web.xml配置文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1"><display-name>T224_Z</display-name><filter><filter-name>encodingFiter</filter-name><filter-class>com.zking.util.EncodingFiter</filter-class></filter><filter-mapping><filter-name>encodingFiter</filter-name><url-pattern>/*bookServletcom.zking.web.BookServletbookServlet/bookServlet  	

这里利用了上面所提到的EncodingFiter类处理中文乱码。

bookList.jsp

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

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title heretitle>
head>
<body>
<h2>小说目录h2><br><form action="${pageContext.request.contextPath}/bookServlet"method="post">
<input type="hidden" name="pagination" value="false">书名：<input type="text" name="bname"> <input type="submit"value="确定">form><table border="1" width="100%"><tr><td>编号td><td>名称td><td>价格td>tr><c:forEach items="${bookList }" var="b"><tr><td>${b.bid }td><td>${b.bname }td><td>${b.price }td>tr>c:forEach>table><z:page pageBean="${pagebean }">z:page>body>
html>

输出结果如下：

如想了解更多，联系博主。

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