JavaWeb之分页查询
时间：2016-12-11 01:41
1、分页的优点：
只查询一页，不需要查询所有数据，能够提高效率。
2、分页数据
页面的数据都是由Servlet传递的
* 当前页：pageCode
> 如果页面没有向Servlet传递页码，那么Servlet默认为第一页，否则按照传递页码为准。
* 总页数：totalPages
> 总记录数 / 每页记录数
* 总记录数：totalRecord
> Dao来获取，select count(*) from customer
* 每页记录数：称为业务数据或系统数据。
* 当前页数据：beanList
* URL
3、数据的传递
这些分页数据总要在各层之间来回传递，可以把这些分页数据封装到一个JavaBean中，它就叫分页Bean，例如：PageBean。
import java.util.List;
public class PageBean<T> {
// 当前页码pageCode
private int pageCode;
/*
* 总页数
* 通过计算得出，不允许外界设置值
* 因为只能get，所以不需要成员变量，通过计算即可得出
*/
// private int totalPages;
// 总记录数
private int totalRecord;
// 每页记录数
private int pageSize;
// 当前页的记录
private List<T> beanList;
public int getPageCode() {
return pageCode;
}
public void setPageCode(int pageCode) {
this.pageCode = pageCode;
}
public int getTotalPages() {
/*
* 计算总页数
* 通过总记录数和每页记录数来计算总页数，当存在余数时，总页数 + 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、分页在各层中的处理
* 页面：给出分页相关的链接。
> 页面需要给Servlet传递当前页码。
* Servlet：创建PageBean对象， 给PageBean对象所有的属性赋值，然后传递给页面。
> 给Dao传递当前页码和每页记录数。
* Service：略
* Dao
> 负责获取：totalRecord，select count(*) from customer
> 负责获取：BeanList<T>，select * from customer limit x, y，从x行开始，查询y行。
> limit计算公式：（当前页-1） * 每页记录数，得出的就是起始行
5、显示分页页码列表
1 2 3 4 5 6 7 8 9 10
* 最多显示多少个页码？
> 暂定10个
* 当前页在页码列表中的位置？
> 暂定为6
只需要pageCode就可以完成页码列表，需要使用pageCode来推算出起始页码（begin）和结束页码（end）
计算公式：
* 如果总页数 <= 10（列表长度），那么begin = 1，end = 总页数
* 如果总页数 > 10，使用公式计算
> begin = pageCode - 5
> end = pageCode + 4
> begin溢出：当begin小于1时，让begin = 1
> end溢出：当end > totalPages时，让end = totalPages
6、在超链接中保留请求参数
当使用多条件查询时，如果点击其它超链接，会丢失原超链接中的参数，也就是丢失请求条件，所以需要在页面的所有超链接中都要保留参数。
可以把?后的全部参数用一个字符串保存到PageBean的URL属性中，这个任务交给Servlet。
然后在页面中使用${pageBean.url }来设置超链接。
——项目代码
===============================================================================
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;
/**
* 持久层 通过QueryRunner来操作数据库
*
* @author 31067
*
*/
public class CustomerDao {
private QueryRunner qr = new TxQueryRunner();
// /*
// * 查询全部客户信息
// */
// 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、创建PageBean对象 2、设置PageBean对象的pageCode和pageSize
* 3、得到totalRecord，设置给pageBean 4、得到beanList，设置给pageBean 5、返回pageBean
*/
PageBean<Customer> pageBean = new PageBean<Customer>();
/*
* 设置pageCode、pageSize
*/
pageBean.setPageCode(pageCode);
pageBean.setPageSize(pageSize);
/*
* 得到totalRecord
*/
String sql = "select count(*) from customer";
// 返回值类型是Object，强转为Number类型
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 ?, ?";
// (当前页码 - 1) * 每行记录数 = 起始行
Object[] params = { (pageCode - 1) * pageSize, pageSize };
List<Customer> beanList = qr.query(sql, new BeanListHandler<Customer>(Customer.class), params);
pageBean.setBeanList(beanList);
pageBean.setBeanList(beanList);
return pageBean;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
/**
* 多条件组合查询
*
* @param criteria
* @return
*/
// public List<Customer> query(Customer criteria) {
// /*
// * 1、给出SQL模板
// * 2、给出参数
// * 3、调用query()方法
// * 结果集处理器：BeanListHandler
// */
//
// // 给出SQL语句的前半部分
// StringBuilder sql = new
// StringBuilder("select * from customer where 1 = 1");
// /*
// * 1、判断条件，向SQL语句中追加where子句
// * 因为不能确定是否包含该参数，所以需要使用if语句来判断
// * 2、给出参数
// * 因为不能确定?占位符所对应的参数，所以在判断参数时，就要添加参数
// * 使用ArrayList来装载参数
// */
//
// // 装载参数
// List<Object> params = new ArrayList<Object>();
//
//
// String cname = criteria.getCname();
// if(cname != null && !cname.trim().isEmpty())
// {
// sql.append(" and cname = ?");
// //模糊查询
// 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 + "%");
// }
//
// /*
// * 执行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、创建PageBean对象 2、设置已有属性，pageCode和pageSize 3、得到totalRecord
* 4、得到BeanList
*/
/*
* 创建PageBean对象，设置已有属性
*/
PageBean<Customer> pageBean = new PageBean<Customer>();
pageBean.setPageCode(pageCode);
pageBean.setPageSize(pageSize);
/*
* 得到tr，需要根据条件进行查询
*/
// 给出SQL语句的前半部分
StringBuilder countSql = new StringBuilder("select count(*) from customer");
StringBuilder whereSql = new StringBuilder(" where 1 = 1");
/*
* 1、判断条件，向SQL语句中追加where子句 因为不能确定是否包含该参数，所以需要使用if语句来判断 2、给出参数
* 因为不能确定?占位符所对应的参数，所以在判断参数时，就要添加参数 使用ArrayList来装载参数
*/
// 装载参数
List<Object> params = new ArrayList<Object>();
String cname = criteria.getCname();
if (cname != null && !cname.trim().isEmpty()) {
whereSql.append(" and cname like ?");
// 模糊查询
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 + "%");
}
/*
* 执行SQL语句 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");
/*
* 查询beanList这一步还需要给出limit子句
*/
StringBuilder limitSql = new StringBuilder(" limit ?,?");
/*
* params中需要给出limit后对应的参数值
*/
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
/**
* 领域对象
* 与表单和数据库表对应
*/
public class Customer {
/*
* 对应数据库表：
* 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;//主键
private String cname;//客户姓名
private String gender;//性别
private String birthday;//客户生日
private String cellphone;//客户手机
private String email;//客户邮箱
private String description;//客户信息描述
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;
/**
* 业务层 依赖Dao
*/
public class CustomerService {
private CustomerDao customerDao = new CustomerDao();
// /**
// * 查询所有客户
// * @return
// */
// public List<Customer> findAll(){
// return customerDao.findAll();
// }
public PageBean<Customer> findAll(int pageCode, int pageSize) {
return customerDao.findAll(pageCode, pageSize);
}
/**
* 多条件组合查询
*
* @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层
*
* @author 31067
*
*/
public class CustomerServlet extends BaseServlet {
private CustomerService customerService = new CustomerService();
// public String findAll(HttpServletRequest request, HttpServletResponse
// response) throws ServletException, IOException {
// /*
// * 1、调用service得到所有客户
// * 2、将全部信息保存到request域中
// * 3、转发到list.jsp
// */
// request.setAttribute("cstmList", customerService.findAll());
// return "f:/list.jsp";
// }
public String findAll(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
/*
* 1、获取页面传递的pageCode
* 2、给定pageSize的值
* 2、给定pageSize的值
* 3、使用pageCode和pageSize调用Service方法，得到PageBean对象
* 4、将PageBean对象保存到request域中
* 5、转发到list.jsp
* 5、转发到list.jsp
*/
/*
* 1、得到pageCode有两种可能
* 如果pageCode参数不存在，说明pageCode = 1
* 如果pageCode参数不存在，说明pageCode = 1
* 如果pageCode参数存在，只需要将参数转换成int类型即可
*/
int pageCode = getPageCode(request);
/*
* 2、给定pageSize的值，每页10行
*/
int pageSize = 10;
/*
* 3、调用Service的findAll方法
* 传递pageCode和pageSize给Service方法
* 返回PageBean对象
* 传递pageCode和pageSize给Service方法
* 返回PageBean对象
*/
PageBean<Customer> pageBean = customerService.findAll(pageCode, pageSize);
/*
* 添加URL及参数
*/
pageBean.setUrl(getUrl(request));
/*
* 4、将PageBean对象保存到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、封装表单数据到Customer对象中，它只有四个属性：cname、gender、cellphone、email
// * 它其实就是一个查询条件的组合对象
// * 2、调用Service的query()方法，得到List<Customer>
// * 3、将List<Customer>保存到request域中
// * 4、转发到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、把条件参数封装到Customer对象中 1、获取页面传递的pageCode 2、给定pageSize的值
* 3、使用pageCode和pageSize以及条件字符串调用Service方法，得到PageBean对象
* 4、将PageBean对象保存到request域中 5、转发到list.jsp
*/
// 获取查询条件
Customer criteria = CommonUtils.toBean(request.getParameterMap(), Customer.class);
/*
* 处理GET请求方式编码问题
*/
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";
}
/**
* 处理数据的编码问题
*
* @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;
}
/**
* 截取请求URL /项目名/Servlet路径?参数字符串
*
* @param request
* @return
*/
private String getUrl(HttpServletRequest request) {
// 获取项目名
String contextPath = request.getContextPath();
// 获取ServletPath，即/CustomerServlet
String servletPath = request.getServletPath();
// 获取问号之后的参数部分
String queryString = request.getQueryString();
/*
* 判断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>
<!-- 默认配置 -->
<default-config>
<!-- 连接四大参数配置 -->
<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>
<!-- 连接池参数配置 -->
<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>主页</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>性别</th>
<th>生日</th>
<th>手机号码</th>
<th>邮箱</th>
<th>描述</th>
</tr>
<%--
要遍历的是pageBean对象的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=${cstm.cid }'/>">编辑</a>
<a href="<c:url value='/CustomerServlet?method=delete&cid=${cstm.cid }'/>">删除</a>
</td>
</tr>
</c:forEach>
</table>
<%--
给出分页相关的链接
--%>
<center>
<%-- 因为pageBean中保存了当前页的URL，并且包括项目名和Servlet路径与参数，所以可以不用<c:url />进行设置了 --%>
<%-- 因为pageBean中的URL不包含pageCode，所以依然需要手动添加 --%>
<a href="${pageBean.url }&pageCode=1" >首页</a>
<c:if test="${pageBean.pageCode > 1 }">
<a href="${pageBean.url }&pageCode=${pageBean.pageCode-1 }" >上一页</a>
</c:if>
<%-- 分页页码列表 --%>
<%-- 计算begin和end --%>
<c:choose>
<%-- 当总页数小于10，那么就把所有的页数都显示出来 --%>
<c:when test="${pageBean.totalPages <= 10 }">
<c:set var="begin" value="1" />
<c:set var="end" value="${pageBean.totalPages }" />
</c:when>
<%-- 当总页数 >= 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" />
<%-- 因为begin已经溢出，所以表示总页数不足10页 --%>
<c:set var="end" value="${pageBean.totalPages }" />
</c:if>
<%-- end溢出 --%>
<c:if test="${end > pageBean.totalPages }">
<%-- 因为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>
<%-- 循环显示页码列表 --%>
<c:forEach var="i" begin="${begin }" end="${end }">
<c:choose>
<%-- 当前页码与页码列表相同时，输出简单文本 --%>
<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 }" >下一页</a>
</c:if>
<a href="${pageBean.url }&pageCode=${pageBean.totalPages }" >尾页</a>
第${pageBean.pageCode }页/共${pageBean.totalPages }页
</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">高级搜索</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">客户名称</td>
<td>
<input type="text" name="cname" />
</td>
</tr>
<tr>
<td>客户性别</td>
<td>
<select name="gender">
<option value="">请选择</option>
<option value="男">男</option>
<option value="女">女</option>
</select>
</td>
</tr>
<tr>
<td>手机</td>
<td>
<input type="text" name="cellphone" />
</td>
</tr>
<tr>
<td>邮箱</td>
<td>
<input type="text" name="email" />
</td>
</tr>
<tr>
<td> </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>
<!-- 它的作用是为本页面中所有的表单和超链接指定显示内容的框架 -->
<!-- 在base中写targe，相当于在本页面中的所有a标签中添加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>客户关系管理系统</h1>
<a href="<c:url value='/add.jsp'/>">添加客户</a> |
<a href="<c:url value='/CustomerServlet?method=findAll' />">查询客户</a> |
<a href="<c:url value='/query.jsp'/>">高级搜索</a> |
<a href="<c:url value='/welcome.jsp' />">返回首页</a>
</body>
</html>
