JavaWeb之分頁查詢

 

時間：2016-12-11 01:41

 

 

1、分頁的優點：
    只查詢一頁，不需要查詢所有數據，能夠提高效率。

2、分頁數據
    頁面的數據都是由Servlet傳遞的

    *   當前頁：pageCode
        >   如果頁面沒有向Servlet傳遞頁碼，那么Servlet默認為第一頁，否則按照傳遞頁碼為准。
    *   總頁數：totalPages
        >   總記錄數 / 每頁記錄數
    *   總記錄數：totalRecord
        >   Dao來獲取，select count(*) from customer
    *   每頁記錄數：稱為業務數據或系統數據。
    *   當前頁數據：beanList
    *   URL

3、數據的傳遞
    這些分頁數據總要在各層之間來回傳遞，可以把這些分頁數據封裝到一個JavaBean中，它就叫分頁Bean，例如：PageBean。

import java.util.List;

 

public class PageBean<T> {

    // 當前頁碼pageCode

    private int pageCode;

 

    /*

     * 總頁數

     * 通過計算得出，不允許外界設置值

     * 因為只能get，所以不需要成員變量，通過計算即可得出

     */

    // private int totalPages;

 

    // 總記錄數

    private int totalRecord;

 

    // 每頁記錄數

    private int pageSize;

 

    // 當前頁的記錄

    private List<T> beanList;

 

    public int getPageCode() {

        return pageCode;

    }

 

    public void setPageCode(int pageCode) {

        this.pageCode = pageCode;

    }

 

    public int getTotalPages() {

        /*

         * 計算總頁數

         * 通過總記錄數和每頁記錄數來計算總頁數，當存在余數時，總頁數 + 1

         */

        int totalPages = totalRecord / pageSize;

            return totalRecord % pageSize == 0 ? totalPages : totalPages + 1;

    }

 

    // public void setTotalPages(int totalPages) {

    // this.totalPages = totalPages;

    // }

 

    public int getTotalRecord() {

        return totalRecord;

    }

 

    public void setTotalRecord(int totalRecord) {

        this.totalRecord = totalRecord;

    }

 

    public int getPageSize() {

        return pageSize;

    }

    public void setPageSize(int pageSize) {

        this.pageSize = pageSize;

    }

 

    public List<T> getBeanList() {

        return beanList;

    }

 

    public void setBeanList(List<T> beanList) {

        this.beanList = beanList;

    }

 

    @Override

    public String toString() {

        return "PageBean [pageCode=" + pageCode + ", totalPages=" + ", totalRecord=" + totalRecord + ", pageSize=" + pageSize + ", beanList=" + beanList + "]";
    }

 

    public PageBean(int pageCode, int totalRecord, int pageSize, List<T> beanList) {

        super();

        this.pageCode = pageCode;

        this.totalRecord = totalRecord;

        this.pageSize = pageSize;

        this.beanList = beanList;

    }

 

    public PageBean() {

        super();

    }

}

4、分頁在各層中的處理

    *   頁面：給出分頁相關的鏈接。
        >   頁面需要給Servlet傳遞當前頁碼。
    *   Servlet：創建PageBean對象， 給PageBean對象所有的屬性賦值，然后傳遞給頁面。
        >   給Dao傳遞當前頁碼和每頁記錄數。
    *   Service：略
    *   Dao
        >   負責獲取：totalRecord，select count(*) from customer
        >   負責獲取：BeanList<T>，select * from customer limit x, y，從x行開始，查詢y行。
        >   limit計算公式：（當前頁-1） * 每頁記錄數，得出的就是起始行




5、顯示分頁頁碼列表

1 2 3 4 5 6 7 8 9 10

    *   最多顯示多少個頁碼？
        >   暫定10個
    *   當前頁在頁碼列表中的位置？
        >   暫定為6

    只需要pageCode就可以完成頁碼列表，需要使用pageCode來推算出起始頁碼（begin）和結束頁碼（end）

    計算公式：
        *   如果總頁數 <= 10（列表長度），那么begin = 1，end = 總頁數
        *   如果總頁數 > 10，使用公式計算
            >   begin = pageCode - 5
            >   end = pageCode + 4
            >   begin溢出：當begin小於1時，讓begin = 1
            >   end溢出：當end > totalPages時，讓end = totalPages

6、在超鏈接中保留請求參數

    當使用多條件查詢時，如果點擊其它超鏈接，會丟失原超鏈接中的參數，也就是丟失請求條件，所以需要在頁面的所有超鏈接中都要保留參數。

    可以把?后的全部參數用一個字符串保存到PageBean的URL屬性中，這個任務交給Servlet。
    然后在頁面中使用${pageBean.url }來設置超鏈接。


——項目代碼




===============================================================================

com.wyc.cstm.dao.CustomerDao

import java.util.ArrayList;

import java.util.List;

 

import org.apache.commons.dbutils.QueryRunner;

import org.apache.commons.dbutils.handlers.BeanListHandler;

import org.apache.commons.dbutils.handlers.ScalarHandler;

 

import com.wyc.cstm.domain.Customer;

import com.wyc.cstm.domain.PageBean;

import com.wyc.jdbc.TxQueryRunner;

 

/**

 * 持久層 通過QueryRunner來操作數據庫

 * 

 * @author 31067

 * 

 */

public class CustomerDao {

    private QueryRunner qr = new TxQueryRunner();

 

    // /*

    // * 查詢全部客戶信息

    // */

    // public List<Customer> findAll() {

    // try {

    // String sql = "select * from customer";

    // return qr.query(sql, new BeanListHandler<Customer>(Customer.class));

    // } catch (Exception e) {

    // throw new RuntimeException(e);

    // }

    // }

 

    public PageBean<Customer> findAll(int pageCode, int pageSize) {

        try {

            /*

             * 1、創建PageBean對象 2、設置PageBean對象的pageCode和pageSize

             * 3、得到totalRecord，設置給pageBean 4、得到beanList，設置給pageBean 5、返回pageBean

             */

            PageBean<Customer> pageBean = new PageBean<Customer>();

            /*

             * 設置pageCode、pageSize

             */

            pageBean.setPageCode(pageCode);

            pageBean.setPageSize(pageSize);

 

            /*

             * 得到totalRecord

             */

            String sql = "select count(*) from customer";

            // 返回值類型是Object，強轉為Number類型

            Number num = (Number) qr.query(sql, new ScalarHandler());

            int totalRecord = num.intValue();

            pageBean.setTotalRecord(totalRecord);

 

            /*

             * 得到beanList

             */

            sql = "select * from customer order by cname limit ?, ?";

            // (當前頁碼 - 1) * 每行記錄數 = 起始行

            Object[] params = { (pageCode - 1) * pageSize, pageSize };

            List<Customer> beanList = qr.query(sql, new BeanListHandler<Customer>(Customer.class), params);

            pageBean.setBeanList(beanList);

 

            return pageBean;

        } catch (Exception e) {

            throw new RuntimeException(e);

        }

    }

 

    /**

     * 多條件組合查詢

     * 

     * @param criteria

     * @return

     */

    // public List<Customer> query(Customer criteria) {

    // /*

    // * 1、給出SQL模板

    // * 2、給出參數

    // * 3、調用query()方法

    // * 結果集處理器：BeanListHandler

    // */

    //

    // // 給出SQL語句的前半部分

    // StringBuilder sql = new

    // StringBuilder("select * from customer where 1 = 1");

    // /*

    // * 1、判斷條件，向SQL語句中追加where子句

    // * 因為不能確定是否包含該參數，所以需要使用if語句來判斷

    // * 2、給出參數

    // * 因為不能確定?占位符所對應的參數，所以在判斷參數時，就要添加參數

    // * 使用ArrayList來裝載參數

    // */

    //

    // // 裝載參數

    // List<Object> params = new ArrayList<Object>();

    //

    //

    // String cname = criteria.getCname();

    // if(cname != null && !cname.trim().isEmpty())

    // {

    // sql.append(" and cname = ?");

    // //模糊查詢

    // params.add("%" + cname + "%");

    // }

    //

    // String gender = criteria.getGender();

    // if(gender != null && !gender.trim().isEmpty())

    // {

    // sql.append(" and gender = ?");

    // params.add(gender);

    // }

    //

    // String cellphone = criteria.getCellphone();

    // if(cellphone != null && !cellphone.trim().isEmpty())

    // {

    // sql.append(" and cellphone = ?");

    // params.add("%" + cellphone + "%");

    // }

    //

    // String email = criteria.getEmail();

    // if(email != null && !email.trim().isEmpty())

    // {

    // sql.append(" and email = ?");

    // params.add("%" + email + "%");

    // }

    //

    // /*

    // * 執行query

    // */

    // try {

    // return qr.query(sql.toString(), new

    // BeanListHandler<Customer>(Customer.class), params.toArray());

    // } catch (SQLException e) {

    // throw new RuntimeException(e);

    // }

    // }

 

    public PageBean<Customer> query(Customer criteria, int pageCode, int pageSize) {

        try {

            /*

             * 1、創建PageBean對象 2、設置已有屬性，pageCode和pageSize 3、得到totalRecord

             * 4、得到BeanList

             */

            /*

             * 創建PageBean對象，設置已有屬性

             */

            PageBean<Customer> pageBean = new PageBean<Customer>();

            pageBean.setPageCode(pageCode);

            pageBean.setPageSize(pageSize);

 

            /*

             * 得到tr，需要根據條件進行查詢

             */

 

            // 給出SQL語句的前半部分

            StringBuilder countSql = new StringBuilder("select count(*) from customer");

            StringBuilder whereSql = new StringBuilder(" where 1 = 1");

            /*

             * 1、判斷條件，向SQL語句中追加where子句 因為不能確定是否包含該參數，所以需要使用if語句來判斷 2、給出參數

             * 因為不能確定?占位符所對應的參數，所以在判斷參數時，就要添加參數 使用ArrayList來裝載參數

             */

 

            // 裝載參數

            List<Object> params = new ArrayList<Object>();

 

            String cname = criteria.getCname();

            if (cname != null && !cname.trim().isEmpty()) {

                whereSql.append(" and cname like ?");

                // 模糊查詢

                params.add("%" + cname + "%");

            }

 

            String gender = criteria.getGender();

            if (gender != null && !gender.trim().isEmpty()) {

                whereSql.append(" and gender = ?");

                params.add(gender);

            }

 

            String cellphone = criteria.getCellphone();

            if (cellphone != null && !cellphone.trim().isEmpty()) {

                whereSql.append(" and cellphone like ?");

                params.add("%" + cellphone + "%");

            }

            String email = criteria.getEmail();

            if (email != null && !email.trim().isEmpty()) {

                whereSql.append(" and email like ?");

                params.add("%" + email + "%");

            }

 

            /*

             * 執行SQL語句 select count(*) from customer = where ....

             */

            Number num = (Number) qr.query(countSql.append(whereSql).toString(), new ScalarHandler(), params.toArray());
 

            int totalRecord = num.intValue();

            pageBean.setTotalRecord(totalRecord);

 

            /*

             * 得到beanList

             */

            StringBuilder sql = new StringBuilder("select * from customer");

 

            /*

             * 查詢beanList這一步還需要給出limit子句

             */

            StringBuilder limitSql = new StringBuilder(" limit ?,?");

 

            /*

             * params中需要給出limit后對應的參數值

             */

            params.add((pageCode - 1) * pageSize);

            params.add(pageSize);

 

            List<Customer> beanList = qr.query(sql.append(whereSql).append(limitSql).toString(), new BeanListHandler<Customer>(Customer.class), params.toArray());

            pageBean.setBeanList(beanList);

 

            return pageBean;

        } catch (Exception e) {

            throw new RuntimeException(e);

        }

    }

}

===============================================================================

com.wyc.cstm.domain.Customer

/**

 * 領域對象

 * 與表單和數據庫表對應

 */

public class Customer {

    /*

     * 對應數據庫表：

     * cid CHAR(32) PRIMARY KEY,

     * cname VARCHAR(40) NOT NULL,

     * gender VARCHAR(6) NOT NULL,

     * birthday CHAR(10),

     * cellphone VARCHAR(15),

     * email VARCHAR(40),

     * description VARCHAR(500)

     */

    private String cid;//主鍵

    private String cname;//客戶姓名

    private String gender;//性別

    private String birthday;//客戶生日

    private String cellphone;//客戶手機

    private String email;//客戶郵箱

    private String description;//客戶信息描述

    public String getCid() {

        return cid;

    }

    public void setCid(String cid) {

        this.cid = cid;

    }

    public String getCname() {

        return cname;

    }

    public void setCname(String cname) {

        this.cname = cname;

    }

    public String getGender() {

        return gender;

    }

    public void setGender(String gender) {

        this.gender = gender;

    }

    public String getBirthday() {

        return birthday;

    }

    public void setBirthday(String birthday) {

        this.birthday = birthday;

    }

    public String getCellphone() {

        return cellphone;

    }

    public void setCellphone(String cellphone) {

        this.cellphone = cellphone;

    }

    public String getEmail() {

        return email;

    }

    public void setEmail(String email) {

        this.email = email;

    }

    public String getDescription() {

        return description;

    }

    public void setDescription(String description) {

        this.description = description;

    }

    @Override

    public String toString() {

        return "Customer [cid=" + cid + ", cname=" + cname + ", gender=" + gender + ", birthday=" + birthday + ", cellphone=" + cellphone + ", email=" + email + ", description=" + description + "]";

    }

    public Customer(String cid, String cname, String gender, String birthday, String cellphone, String email, String description) {

        super();

        this.cid = cid;

        this.cname = cname;

        this.gender = gender;

        this.birthday = birthday;

        this.cellphone = cellphone;

        this.email = email;

        this.description = description;

    }

    public Customer() {

        super();

    }

}

===============================================================================

com.wyc.cstm.service.CustomerService

import com.wyc.cstm.dao.CustomerDao;

import com.wyc.cstm.domain.Customer;

import com.wyc.cstm.domain.PageBean;

 

/**

 * 業務層 依賴Dao

 */

public class CustomerService {

    private CustomerDao customerDao = new CustomerDao();

 

    // /**

    // * 查詢所有客戶

    // * @return

    // */

    // public List<Customer> findAll(){

    // return customerDao.findAll();

    // }

 

    public PageBean<Customer> findAll(int pageCode, int pageSize) {

        return customerDao.findAll(pageCode, pageSize);

    }

 

    /**

     * 多條件組合查詢

     * 

     * @param criteria

     * @return

     */

    public PageBean<Customer> query(Customer criteria, int pageCode, int pageSize) {

        return customerDao.query(criteria, pageCode, pageSize);

    }

}

===============================================================================

com.wyc.cstm.web.servlet.CustomerServlet

import java.io.IOException;

 

import javax.servlet.ServletException;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import com.wyc.bean.CommonUtils;

import com.wyc.cstm.domain.Customer;

import com.wyc.cstm.domain.PageBean;

import com.wyc.cstm.service.CustomerService;

import com.wyc.servlet.BaseServlet;

 

/**

 * Web層

 * 

 * @author 31067

 * 

 */

public class CustomerServlet extends BaseServlet {

 

    private CustomerService customerService = new CustomerService();

 

    // public String findAll(HttpServletRequest request, HttpServletResponse

    // response) throws ServletException, IOException {

    // /*

    // * 1、調用service得到所有客戶

    // * 2、將全部信息保存到request域中

    // * 3、轉發到list.jsp

    // */

    // request.setAttribute("cstmList", customerService.findAll());

    // return "f:/list.jsp";

    // }

 

    public String findAll(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        /*

         * 1、獲取頁面傳遞的pageCode
         * 2、給定pageSize的值

         * 3、使用pageCode和pageSize調用Service方法，得到PageBean對象

         * 4、將PageBean對象保存到request域中
         * 5、轉發到list.jsp

         */

        /*

         * 1、得到pageCode有兩種可能
         *     如果pageCode參數不存在，說明pageCode = 1

         *     如果pageCode參數存在，只需要將參數轉換成int類型即可

         */

        int pageCode = getPageCode(request);

 

        /*

         * 2、給定pageSize的值，每頁10行

         */

        int pageSize = 10;

 

        /*

         * 3、調用Service的findAll方法
         *     傳遞pageCode和pageSize給Service方法
         *     返回PageBean對象

         */

        PageBean<Customer> pageBean = customerService.findAll(pageCode, pageSize);

        /*

         * 添加URL及參數

         */

        pageBean.setUrl(getUrl(request));

        /*

         * 4、將PageBean對象保存到request域中

         */

        request.setAttribute("pageBean", pageBean);

 

        return "f:list.jsp";

    }

 

    private int getPageCode(HttpServletRequest request) {

        String value = request.getParameter("pageCode");

        if (value == null || value.trim().isEmpty()) {

            return 1;

        }

            return Integer.parseInt(value);

    }

 

    // public String query(HttpServletRequest request, HttpServletResponse

    // response) throws ServletException, IOException {

    // /*

    // * 1、封裝表單數據到Customer對象中，它只有四個屬性：cname、gender、cellphone、email

    // * 它其實就是一個查詢條件的組合對象

    // * 2、調用Service的query()方法，得到List<Customer>

    // * 3、將List<Customer>保存到request域中

    // * 4、轉發到list.jsp

    // */

    //

    // Customer criteria = CommonUtils.toBean(request.getParameterMap(),

    // Customer.class);

    // List<Customer> cstmList = customerService.query(criteria);

    // request.setAttribute("cstmList", cstmList);

    // return "f:list.jsp";

    // }

    public String query(HttpServletRequest request, HttpServletResponse response) throws Exception {

        /*

        * 0、把條件參數封裝到Customer對象中 1、獲取頁面傳遞的pageCode 2、給定pageSize的值

        * 3、使用pageCode和pageSize以及條件字符串調用Service方法，得到PageBean對象

        * 4、將PageBean對象保存到request域中 5、轉發到list.jsp

        */

        // 獲取查詢條件

        Customer criteria = CommonUtils.toBean(request.getParameterMap(), Customer.class);

 

        /*

        * 處理GET請求方式編碼問題

        */

        criteria = encoding(criteria);

        int pageCode = getPageCode(request);

        int pageSize = 10;

 

        PageBean<Customer> pageBean = customerService.query(criteria, pageCode, pageSize);

 

        /*

        * 得到URL，保存到pageBean中

        */

        pageBean.setUrl(getUrl(request));

 

        request.setAttribute("pageBean", pageBean);

 

        return "f:list.jsp";

    }

 

    /**

    * 處理數據的編碼問題

    * 

    * @throws Exception

    */

    private Customer encoding(Customer criteria) throws Exception {

        String cname = criteria.getCname();

        String gender = criteria.getGender();

        String cellphone = criteria.getCellphone();

        String email = criteria.getEmail();

 

        if (cname != null && !cname.trim().isEmpty()) {

            cname = new String(cname.getBytes("iso-8859-1"), "utf-8");

            criteria.setCname(cname);

        }

        if (gender != null && !gender.trim().isEmpty()) {

            gender = new String(gender.getBytes("iso-8859-1"), "utf-8");

            criteria.setGender(gender);

        }

        if (cellphone != null && !cellphone.trim().isEmpty()) {

            cellphone = new String(cellphone.getBytes("iso-8859-1"), "utf-8");

            criteria.setCellphone(cellphone);

        }

        if (email != null && !email.trim().isEmpty()) {

            email = new String(email.getBytes("iso-8859-1"), "utf-8");

            criteria.setEmail(email);

        }

 

        return criteria;

    }
 

    /**

    * 截取請求URL /項目名/Servlet路徑?參數字符串

    * 

    * @param request

    * @return

    */

    private String getUrl(HttpServletRequest request) {

        // 獲取項目名

        String contextPath = request.getContextPath();

 

        // 獲取ServletPath，即/CustomerServlet

        String servletPath = request.getServletPath();

 

        // 獲取問號之后的參數部分

        String queryString = request.getQueryString();

 

        /*

        * 判斷queryString中是否包含pageCode 如果包含，需要截取掉pageCode

        */

        if (queryString.contains("&pageCode=")) {

            int index = queryString.lastIndexOf("&pageCode=");

            queryString = queryString.substring(0, index);

        }

 

        return contextPath + servletPath + "?" + queryString;

    }

}

===============================================================================

c3p0-config.xml

<?xml version="1.0" encoding="UTF-8"?>

<c3p0-config>

    <!-- 默認配置 -->

    <default-config>

        <!-- 連接四大參數配置 -->

        <property name="jdbcUrl">jdbc:mysql://localhost:3306/customers</property>

        <property name="driverClass">com.mysql.jdbc.Driver</property>

        <property name="user">root</property>

        <property name="password">Admin123</property>

        <!-- 連接池參數配置 -->

        <property name="acquireIncrement">3</property>

        <property name="initialPoolSize">10</property>

        <prpperty name="minPoolSize">2</prpperty>

        <property name="maxPoolSize">10</property>

    </default-config>

</c3p0-config>

 

 

 

===============================================================================

frame.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@ taglib prefix="c" uri=" http://java.sun.com/jsp/jstl/core" %>

<%

    String path = request.getContextPath();

    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";

%>

 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<base href="<%=basePath%>">

 

<title>主頁</title>

<meta http-equiv="pragma" content="no-cache">

<meta http-equiv="cache-control" content="no-cache">

<meta http-equiv="expires" content="0">

<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

<meta http-equiv="description" content="This is my page">

 

</head>

    <frameset rows="20%, *" >

        <frame src="<c:url value='/top.jsp'/>" name="top">

        <frame src="<c:url value='/welcome.jsp'/>" name="main">

    </frameset>

</html>

 

===============================================================================

list.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@ taglib prefix="c" uri=" http://java.sun.com/jsp/jstl/core"%>

 

<%

    String path = request.getContextPath();

    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";

%>

 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<base href="<%=basePath%>">

 

<title>My JSP 'list.jsp' starting page</title>

 

<meta http-equiv="pragma" content="no-cache">

<meta http-equiv="cache-control" content="no-cache">

<meta http-equiv="expires" content="0">

<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

<meta http-equiv="description" content="This is my page">

 

</head>

 

<body>

    <table align="center" border="1px">

        <tr>

            <th>姓名</th>

            <th>性別</th>

            <th>生日</th>

            <th>手機號碼</th>

            <th>郵箱</th>

            <th>描述</th>

        </tr>

        <%--

            要遍歷的是pageBean對象的beanList集合

        --%>

        <c:forEach items="${requestScope.pageBean.beanList }" var="cstm">

            <tr>

                <td>${cstm.cname }</td>

                <td>${cstm.gender }</td>

                <td>${cstm.birthday }</td>

                <td>${cstm.cellphone }</td>

                <td>${cstm.email }</td>

                <td>${cstm.description }</td>

                <td>

                    <a href="<c:url value='/CustomerServlet?method=preEdit&cid=${cstm.cid }'/>">編輯</a>

                    <a href="<c:url value='/CustomerServlet?method=delete&cid=${cstm.cid }'/>">刪除</a>

                </td>

            </tr>

        </c:forEach>

 

    </table>

    <%--

        給出分頁相關的鏈接

 --%>

 <center>

        <%-- 因為pageBean中保存了當前頁的URL，並且包括項目名和Servlet路徑與參數，所以可以不用<c:url />進行設置了 --%>

        <%-- 因為pageBean中的URL不包含pageCode，所以依然需要手動添加 --%>

        <a href="${pageBean.url }&pageCode=1" >首頁</a>

        <c:if test="${pageBean.pageCode > 1 }">

            <a href="${pageBean.url }&pageCode=${pageBean.pageCode-1 }" >上一頁</a>

        </c:if>

 

        <%-- 分頁頁碼列表 --%>

 

        <%-- 計算begin和end --%>

        <c:choose>

            <%-- 當總頁數小於10，那么就把所有的頁數都顯示出來 --%>

            <c:when test="${pageBean.totalPages <= 10 }">

                <c:set var="begin" value="1" />

                <c:set var="end" value="${pageBean.totalPages }" />

            </c:when>

 

            <%-- 當總頁數 >= 10 --%>

            <c:when test="${pageBean.totalPages > 10 }">

                <c:set var="begin" value="${pageBean.pageCode - 5 }" />

                <c:set var="end" value="${pageBean.totalPages + 4 }" />
 

                <%-- begin溢出 --%>

                <c:if test="${begin < 1 }">

                    <c:set var="begin" value="1" />

                    <%-- 因為begin已經溢出，所以表示總頁數不足10頁 --%>

                    <c:set var="end" value="${pageBean.totalPages }" />

                </c:if>

 

                <%-- end溢出 --%>

                <c:if test="${end > pageBean.totalPages }">

                    <%-- 因為end溢出，所以begin = end - 9 --%>

                    <c:set var="begin" value="${pageBean.totalPages - 9 }" />

                    <c:set var="end" value="${pageBean.totalPages }" />

                </c:if>

            </c:when>

        </c:choose>

 

        <%-- 循環顯示頁碼列表 --%>

        <c:forEach var="i" begin="${begin }" end="${end }">

        <c:choose>

            <%-- 當前頁碼與頁碼列表相同時，輸出簡單文本 --%>

            <c:when test="${pageBean.pageCode eq i }">

                [${i }]

           </c:when>

            <c:otherwise>

                <a href="${pageBean.url }&pageCode=${i }">${i }</a>

            </c:otherwise>

        </c:choose>

    </c:forEach>

 

 

    <c:if test="${pageBean.pageCode < pageBean.totalPages }">

        <a href="${pageBean.url }&pageCode=${pageBean.pageCode+1 }" >下一頁</a>

    </c:if>
 

    <a href="${pageBean.url }&pageCode=${pageBean.totalPages }" >尾頁</a>

    第${pageBean.pageCode }頁/共${pageBean.totalPages }頁

 

    </center>

</body>

</html>

 

===============================================================================

query.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@ taglib prefix="c" uri=" http://java.sun.com/jsp/jstl/core"%>

 

<%

    String path = request.getContextPath();

    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";

%>

 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<base href="<%=basePath%>">

 

<title>My JSP 'query.jsp' starting page</title>

 

<meta http-equiv="pragma" content="no-cache">

<meta http-equiv="cache-control" content="no-cache">

<meta http-equiv="expires" content="0">

<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

<meta http-equiv="description" content="This is my page">

 

</head>

 

<body>

    <h3 align="center">高級搜索</h3>

    <form action="<c:url value='/CustomerServlet' />" method="get">

        <input type="hidden" name="method" value="query" />

        <table border="0" align="center" width="40%" style="margin-left: 100px;">

            <tr>

                <td width="100px">客戶名稱</td>

                <td>

                    <input type="text" name="cname" />

                </td>

            </tr>

            <tr>

                <td>客戶性別</td>

                <td>

                    <select name="gender">

                        <option value="">請選擇</option>

                        <option value="男">男</option>

                        <option value="女">女</option>

                    </select>

                </td>

            </tr>

            <tr>

                <td>手機</td>

                <td>

                    <input type="text" name="cellphone" />

                </td>

            </tr>

            <tr>

                <td>郵箱</td>

                <td>

                    <input type="text" name="email" />

                </td>

            </tr>

            <tr>

                <td>&nbsp;</td>

                <td>

                    <input type="submit" value="搜索"/>

                    <input type="reset" value="重置" />

                </td>

             </tr>

        </table>

    </form>

</body>

</html>

 

===============================================================================

top.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@ taglib prefix="c" uri=" http://java.sun.com/jsp/jstl/core"%>

 

<%

    String path = request.getContextPath();

    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";

%>

 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>
 

<!-- 它的作用是為本頁面中所有的表單和超鏈接指定顯示內容的框架 -->

<!-- 在base中寫targe，相當於在本頁面中的所有a標簽中添加target -->

<base target="main">

 

<title>My JSP 'top.jsp' starting page</title>

 

<meta http-equiv="pragma" content="no-cache">

<meta http-equiv="cache-control" content="no-cache">

<meta http-equiv="expires" content="0">

<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

<meta http-equiv="description" content="This is my page">

 

</head>

 

<body style="text-align: center">

    <h1>客戶關系管理系統</h1>

    <a href="<c:url value='/add.jsp'/>">添加客戶</a>  |

    <a href="<c:url value='/CustomerServlet?method=findAll' />">查詢客戶</a> |

    <a href="<c:url value='/query.jsp'/>">高級搜索</a> |

    <a href="<c:url value='/welcome.jsp' />">返回首頁</a>

</body>

</html>