代码

分页实体类

PageBean

下面定义了一些方法用来分页，和昨天的比多了很多，注意修改或添加

package com.rong.book.utils;import java.util.Map;import javax.servlet.http.HttpServletRequest;public class PageBean {private Integer page=1; //页码private Integer rows=3; //页大小private Integer total=0;  //总记录数private boolean pagination=true; //默认 true分页private String url;//请求路径private Map<String, String[]> map;//请求参数集合public PageBean() {super();}public Map<String, String[]> getMap() {return map;}public void setMap(Map<String, String[]> map) {this.map = map;}public Integer getPage() {return page;}public void setPage(Integer page) {this.page = page;}public void setPage(String page) {if(page!=null&& ! "".equals(page)) {this.page =Integer.parseInt(page);}}public Integer getRows() {return rows;}public void setRows(Integer rows) {this.rows = rows;}public void setRows(String rows) {if(rows!=null&&!"".equals(rows)) {this.rows =Integer.parseInt(rows);}}public Integer getTotal() {return total;}public void setTotal(Integer total) {this.total = total;}public void setTotal(String total) {this.total = Integer.parseInt(total);}public String getUrl() {return url;}public void setUrl(String url) {this.url = url;}public boolean isPagination() {return pagination;}public void setPagination(boolean pagination) {this.pagination = pagination;}public void setPagination(String pagination) {if("false".equals(pagination)) {this.pagination =Boolean.parseBoolean(pagination);}}@Overridepublic String toString() {return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + "]";}public int getStartIndex() {return (this.page-1)*this.rows;}public void SetRequest(HttpServletRequest req) {String page=req.getParameter("page");String rows=req.getParameter("rows");String pagination=req.getParameter("pagination");this.setPage(page);this.setRows(rows);this.setPage(pagination);this.setUrl(req.getRequestURI());this.setMap(req.getParameterMap());}public int getMaxPage() {int maxpage=this.total/this.rows;if(this.total%this.rows!=0) {maxpage++;}return maxpage;}/*** 得到上一页* @return*/public int getPerPage() {int perpage=this.page-1;if(perpage<1) {perpage=1;}return perpage;}public int getNextPage() {int nextpage=this.page+1;if(nextpage>this.getMaxPage()) {nextpage=this.getMaxPage();}return nextpage;}}

Dao类方法

主dao类(bookdao.java)

把这个替换昨天的dao最下面一个方法，基本就用这个一个方法实现分页

public List<Book> listBooks(Book book,PageBean pageBean)  {String sql = "SELECT bid,bname,price FROM book WHERE 1=1";if(StringUtils.isNotBlank(book.getBname())) {sql += " AND bname LIKE '%"+book.getBname()+"%'";}return this.exectueQuery(sql, pageBean, new CallBack<Book>() {@Overridepublic List<Book> forEachRs(ResultSet rs) throws SQLException  {List<Book> ls= new ArrayList<Book>();Book b = null;while(rs.next()) {b = new Book();b.setBid(rs.getInt("bid"));b.setBname(rs.getString("bname"));b.setPrice(rs.getFloat("price"));ls.add(b);}return ls;}});}

辅dao类(basedao.java)

package com.rong.book.base;import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;import com.rong.book.utils.DBHelper;
import com.rong.book.utils.PageBean;public class BaseDao<K> {public static interface CallBack<T> {public List<T> forEachRs(ResultSet rs) throws SQLException;}public List<K> exectueQuery(String sql,PageBean pageBean,CallBack<K> callBack)  {Connection con = null;PreparedStatement ps = null;ResultSet rs = null;try {con = DBHelper.getConnection();//1.查询符合条件的总记录if(null!=pageBean && pageBean.isPagination()) {String countSql = this.getCountSql(sql);ps = con.prepareStatement(countSql);rs = ps.executeQuery();if(rs.next()) {Object obj = rs.getInt(1);pageBean.setTotal(obj.toString());}DBHelper.close(null, ps, rs);}//2.查询符合条件的记录if(null!=pageBean && pageBean.isPagination()) {sql = this.pageSql(sql, pageBean);}ps = con.prepareStatement(sql);rs = ps.executeQuery();return callBack.forEachRs(rs);} catch (Exception e) {throw new RuntimeException(e);}finally {DBHelper.close(con, ps, rs);}}/*** 得到查询总记录的sql语句* @param sql* @return*/private String getCountSql(String sql) {String countSql = " SELECT COUNT(1) FROM ("+ sql +") t1 ";return countSql;}/*** 得到分页的sql语句* @param sql* @param pageBean* @return*/private String pageSql(String sql,PageBean pageBean) {String pageSql = sql+" LIMIT "+pageBean.getStartIndex()+","+pageBean.getRows()+"";return pageSql;}
}

servlet类

BookServlet.java

package com.rong.book.action;import java.io.IOException;
import java.util.List;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 javax.servlet.http.HttpSession;import com.rong.book.biz.BookBiz;
import com.rong.book.biz.IBookBiz;
import com.rong.book.entity.Book;
import com.rong.book.utils.PageBean;@WebServlet("/listBook.action")
public class BookServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//1.设置编码req.setCharacterEncoding("utf-8");//2.获取页面传过来的值 String bookname=req.getParameter("bookname");PageBean pageBean = new PageBean();pageBean.SetRequest(req);Book book = new Book();book.setBname(bookname);//3.调用biz层查询IBookBiz bookBiz = new BookBiz();List<Book> bookls=bookBiz.listBooks(book, pageBean);//4.将查询出的集合放到作用域中req.setAttribute("bookls", bookls);req.setAttribute("pagebean", pageBean);req.getRequestDispatcher("listBook.jsp").forward(req, resp);}}

jsp页面代码

进入页面（index.jsp）

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body><a href="listBook.action">查询所有书本</a>
</body>
</html>

展示页面（booklist.jsp）

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>小说城</title>
<script type="text/javascript">function gotopage(page){document.getElementById('pagebeanform').page.value=page;document.getElementById('pagebeanform').submit();}function skippage(maxpage){var page=document.getElementById('skipPage').value;if(isNaN(page)||page<1||page>maxpage){alert("请输入1-"+maxpage+"的数字")}else{gotopage(page);}}</script>
</head>
<body><h2>小说城</h2><form action="listBook.action" method="post">书名:<input type="text" name="bookname"/><input type="submit" value="查询"/></form><table border="1px" width="100%"><tr><td>序号</td><td>书名</td><td>价格</td></tr><c:forEach items="${bookls }" var="b" varStatus="s"><tr><td>${s.count }</td><td>${b.bname }</td><td>${b.price }</td></tr></c:forEach></table><form action="${pagebean.url }" method="post" id="pagebeanform"><input type="hidden" name="page" id="page"/><!-- 请求参数 --></form><div style="width:100%;text-align: right;"><a href="javascript:gotopage(1)">首页</a>&nbsp;<a href='javascript:gotopage("${pagebean.getPerPage() }")'>上一页</a>&nbsp;<a href='javascript:gotopage("${pagebean.getNextPage() }")'>下一页</a>&nbsp;<a href="javascript:gotopage(${pagebean.getMaxPage() })">尾页</a>&nbsp;<input id="skipPage" style="width:30px"/>&nbsp;<a href="javascript:skippage(${pagebean.getMaxPage() })">GO</a>&nbsp;</div></body>
</html>

页面效果

模糊查询

页脚跳转

总结

虽然效果出来了，但是我还是有些地方不是很明白的，也不知道怎么解释；
加油！六一快乐