package cn.itcast.cstm.domain;
import java.util.List;
public class PageBean<T> {
private int pc;// 当前页码page code
//private int tp;// 总页数total page
private int tr;// 总记录数total record
private int ps;// 每页记录数page size
private List<T> beanList;// 当前页的记录
private String url;//它就是url后的条件！
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public int getPc() {
return pc;
}
public void setPc(int pc) {
this.pc = pc;
}
/**
* 计算总页数
* @return
*/
public int getTp() {
// 通过总记录数和每页记录数来计算总页数
int tp = tr / ps;
return tr%ps==0 ? tp : tp+1;
}
// public void setTp(int tp) {
// this.tp = tp;
// }
public int getTr() {
return tr;
}
public void setTr(int tr) {
this.tr = tr;
}
public int getPs() {
return ps;
}
public void setPs(int ps) {
this.ps = ps;
}
public List<T> getBeanList() {
return beanList;
}
public void setBeanList(List<T> beanList) {
this.beanList = beanList;
}
}

第${pb.pc }页/共${pb.tp }页
<a href="${pb.url }&pc=1">首页</a>
<c:if test="${pb.pc > 1 }">
<a href="${pb.url }&pc=${pb.pc-1}">上一页</a>
</c:if>
<%-- 计算begin、end --%>
<c:choose>
<%-- 如果总页数不足10页，那么把所有的页数都显示出来！ --%>
<c:when test="${pb.tp <= 10 }">
<c:set var="begin" value="1" />
<c:set var="end" value="${pb.tp }" />
</c:when>
<c:otherwise>
<%-- 当总页数>10时，通过公式计算出begin和end --%>
<c:set var="begin" value="${pb.pc-5 }" />
<c:set var="end" value="${pb.pc+4 }" /> 
<%-- 头溢出 --%>
<c:if test="${begin < 1 }">
<c:set var="begin" value="1" />
<c:set var="end" value="10" />
</c:if> 
<%-- 尾溢出 --%>
<c:if test="${end > pb.tp }">
<c:set var="begin" value="${pb.tp - 9 }" />
<c:set var="end" value="${pb.tp }" />
</c:if> 
</c:otherwise>
</c:choose>
<%-- 循环遍历页码列表 --%>
<c:forEach var="i" begin="${begin }" end="${end }">
<c:choose>
<c:when test="${i eq pb.pc }">
[${i }]
</c:when>
<c:otherwise>
<a href="${pb.url }&pc=${i}">[${i }]</a> 
</c:otherwise>
</c:choose>
</c:forEach>
<c:if test="${pb.pc < pb.tp }">
<a href="${pb.url }&pc=${pb.pc+1}">下一页</a>
</c:if>
<a href="${pb.url }&pc=${pb.tp}">尾页</a>

package cn.itcast.cstm.web.servlet;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.itcast.commons.CommonUtils;
import cn.itcast.cstm.domain.Customer;
import cn.itcast.cstm.domain.PageBean;
import cn.itcast.cstm.service.CustomerService;
import cn.itcast.servlet.BaseServlet;
public class CustomerServlet extends BaseServlet {
private CustomerService customerService = new CustomerService();
/**
* 获取pc
* 
* @param request
* @return
*/
private int getPc(HttpServletRequest request) {
/*
* 1. 得到pc 如果pc参数不存在，说明pc=1 如果pc参数存在，需要转换成int类型即可
*/
String value = request.getParameter("pc");
if (value == null || value.trim().isEmpty()) {
return 1;
}
return Integer.parseInt(value);
}
//分页servlet
public String query(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// System.out.println(getUrl(request));
/*
* 0. 把条件封装到Customer对象中 1. 得到pc 2. 给定ps 3.
* 使用pc和ps，以及条件对象，调用service方法得到PageBean 4. 把PageBean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 pc = getPc(request);// 得到pc
int ps = 10;// 给定ps的值，第页10行记录
PageBean<Customer> pb = customerService.query(criteria, pc, ps);
// 得到url，保存到pb中
pb.setUrl(getUrl(request));
request.setAttribute("pb", pb);
return "f:/list.jsp";
}
/**
* 处理四样
* 
* @param criteria
* @return
* @throws UnsupportedEncodingException
*/
private Customer encoding(Customer criteria) throws UnsupportedEncodingException {
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url /项目名/Servlet路径?参数字符串
* 
* @param request
* @return
*/
private String getUrl(HttpServletRequest request) {
String contextPath = request.getContextPath();// 获取项目名
String servletPath = request.getServletPath();// 获取servletPath，即/CustomerServlet
String queryString = request.getQueryString();// 获取问号之后的参数部份
// 判断参数部份中是否包含pc这个参数，如果包含，需要截取下去，不要这一部份。
if (queryString.contains("&pc=")) {
int index = queryString.lastIndexOf("&pc=");
queryString = queryString.substring(0, index);
}
return contextPath + servletPath + "?" + queryString;
}
}