分页信息实体（PageBean）

后台分页数据查询

1. 处理流程

2. 实现

前言：在前几篇文章我写了xml，java反射机制，自定义jsp标签，这一篇文章我会运用前几篇文章的知识来写一个通用分页功能。

分页信息实体（PageBean）

用于存储和传递分页参数，主要内容如下：

页码，从页面传递过来
每页行数，从也能传递过来
总记录数，从数据库中统计得到
是否分页，如果为false，则查询所有记录
查询参数，点击上一页或下一页时需要及携带用户输入的所有查询参数
另外提供上页，下页，总页数等计算

参考代码：

package com.zking.util;

import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import com.mysql.jdbc.StringUtils;

public class PageBean {

	/**
	 * 页码
	 */
	private int page = 1;

	/**
	 * 每页显示的记录数
	 */
	private int rows = 10;

	/**
	 * 总记录数
	 */
	private int total = 0;

	/**
	 * 是否分页
	 */
	private boolean pagination = true;
	
	/**
	 * 记录查询的url，以便于点击分页时再次使用
	 */
	private String url;
	
	/**
	 * 存放请求参数，用于生成隐藏域中的元素
	 */
	private Map<String,String[]> parameterMap;
	
	/**
	 * 根据传入的Request初始化分页对象
	 * @param request
	 */
	public void setRequest(HttpServletRequest request) {
		
		if(!StringUtils.isNullOrEmpty(request.getParameter("page"))) {
			this.page = Integer.valueOf(request.getParameter("page"));
		}
		if(!StringUtils.isNullOrEmpty(request.getParameter("rows"))) {
			this.rows = Integer.valueOf(request.getParameter("rows"));
		}
		if(!StringUtils.isNullOrEmpty(request.getParameter("pagination"))) {
			this.pagination = Boolean.valueOf(request.getParameter("pagination"));
		}
		
		this.url = request.getRequestURI();
		this.parameterMap = request.getParameterMap();
		
		request.setAttribute("pageBean", this);
	}


	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 boolean isPagination() {
		return pagination;
	}

	public void setPagination(boolean pagination) {
		this.pagination = pagination;
	}
	
	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public Map<String, String[]> getParameterMap() {
		return parameterMap;
	}

	public void setParameterMap(Map<String, String[]> parameterMap) {
		this.parameterMap = parameterMap;
	}

	//计算起始页码
	public int getStartIndex() {
		return (this.page - 1) * this.rows;
	}
	
	//获取总页数
	public int getTotalPage() {
		if (this.getTotal() % this.rows == 0) {
			return this.getTotal() / this.rows;
		} else {
			return this.getTotal() / this.rows + 1;
		}
	}

	//上一页
	public int getPreviousPage() {
		return this.page - 1 > 0 ? this.page - 1 : 1;
	}
	
	//下一页
	public int getNextPage() {
		return this.page + 1 > getTotalPage() ? getTotalPage() : this.page + 1;
	}
	
}

后台分页数据查询

1. 处理流程

查询满足条件的总记录数
查询满足条件的当前页的数据
上两个步骤的查询条件要一致

流程图：

2. 实现

1.为简化数据库（mysql）操作，需要一个DBUtil工具类。

package com.zking.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DBUtil {

	//获得驱动
	private static String DRIVER_NAME = "com.mysql.jdbc.Driver";

	//连接语句
	private static String DB_URL = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false";

	//用户名
	private static String DB_USER = "root";

	//密码
	private static String DB_PASSWORD = "910814";

	private DBUtil() {
	}

	static {
		//驱动只需要加载一次所以放在静态代码块里
		try {
			Class.forName(DRIVER_NAME);

		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

	public static Connection getConection() throws SQLException {
		Connection connection = DriverManager.getConnection(DB_URL, DB_USER, DB_PASSWORD);
		return connection;
	}

	public static void closeDB(ResultSet rs, Statement ps, Connection con) {

		try {
			if (rs != null && !rs.isClosed()) {
				rs.close();
			}

			if (ps != null && !ps.isClosed()) {
				ps.close();
			}

			if (con != null && !con.isClosed()) {
				con.close();
			}

		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	public static void closeDB(ResultSet rs, Statement ps) {

		try {
			if (rs != null && !rs.isClosed()) {
				rs.close();
			}

			if (ps != null && !ps.isClosed()) {
				ps.close();
			}

		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

}

2.然后写一个Student实体类为例子，及对应的数据库表。

小伙伴们要注意了，我的数据库里的列名class在我的实体类里是clazz，这是应为我写列名的时候忘了class在java中是关键字了〒▽〒，但是我懒得改(。・ω・。)，将就一下吧。

package com.zking.model;

public class Student {

	private Integer sid;
	
	private String sname;
	
	private Integer score;
	
	private String clazz;


	public Integer getSid() {
		return sid;
	}

	public void setSid(Integer sid) {
		this.sid = sid;
	}

	public String getSname() {
		return sname;
	}

	public void setSname(String sname) {
		this.sname = sname;
	}

	public Integer getScore() {
		return score;
	}

	public void setScore(Integer score) {
		this.score = score;
	}

	
	public String getClazz() {
		return clazz;
	}

	public void setClazz(String clazz) {
		this.clazz = clazz;
	}
	
	@Override
	public String toString() {
		return "Student [sid=" + sid + ", sname=" + sname + ", score=" + score + ", clazz=" + clazz + "]";
	}
}

3.分页查询的功能（写一个StudentDao）

package com.zking.util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

import com.zking.model.Student;
import com.zking.util.BaseDao.ICovent;

public class StudentDao {

	public List<Student> getStudents(String sname, PageBean pageBean) {

		// 编写sql语句
		String sql = "select * from student ";
		if (!Objects.isNull(sname) && sname.length() > 0) {
			sql += " where sname like ?";
		}

		List<Student> students = new ArrayList<>();

		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;

		// 不分页的情况
		if (pageBean == null || !pageBean.isPagination()) {
			try {
				con = DBUtil.getConection();
				ps = con.prepareStatement(sql);

				// 设置查询参数
				if (sname != null) {
					ps.setObject(1, sname);
				}
				rs = ps.executeQuery();
				while (rs.next()) {
					Student stu = new Student();
					stu.setSid(rs.getInt("sid"));
					stu.setSname(rs.getString("sname"));
					stu.setScore(rs.getInt("score"));
					stu.setClazz(rs.getString("class"));
					students.add(stu);
				}

			} catch (SQLException e) {
				e.printStackTrace();
			} finally {
				DBUtil.closeDB(rs, ps, con);
			}
		} else {
			// 需要分页的情况
			String countSql = "SELECT COUNT(*) FROM (" + sql + ")tmp";
			try {
				con = DBUtil.getConection();
				ps = con.prepareStatement(sql);

				// 设置查询参数
				if (sname != null) {
					ps.setObject(1, sname);
				}

				rs = ps.executeQuery();

				if (rs.next()) {
					Integer total = rs.getInt(1);
					pageBean.setTotal(total);
				}

				// 判断总记录数是否大于0,如果大于0表示有记录,需要查询当前记录
				// 如果没有就直接返回
				if (pageBean.getTotal() <= 0) {
					return students;
				}
				// 查询当前页的数据
				String pagingSql = sql + "limit" + pageBean.getStartIndex() + "," + pageBean.getRows();
				// 设置查询参数
				if (sname != null) {
					ps.setObject(1, sname);
				}
				rs = ps.executeQuery();
				while (rs.next()) {
					Student stu = new Student();
					stu.setSid(rs.getInt("sid"));
					stu.setSname(rs.getString("sname"));
					stu.setScore(rs.getInt("score"));
					stu.setClazz(rs.getString("class"));
					students.add(stu);
				}

			} catch (SQLException e) {
				e.printStackTrace();
			} finally {
				DBUtil.closeDB(rs, ps, con);
			}
		}

		return students;
	}

	
	
	public static void main(String[] args) {
		StudentDao dao = new StudentDao();
		List<Student> students = dao.getStudents(null, new PageBean());
		students.forEach(t-> System.out.println(t));
	}
}

重构-提取公用方法

（1）为了进行公共方法的抽取，需要找出上面实习中的可通用部分，和差异化部分。

只要是分页，就会统计总记录数，而总记录数的统计是在业务sql外封装了一个select count(*)是有规律可循的，可以通用
只要是分页，则封装分页sql也是有规律可循的（在业务sql后加limit子句即可），可以通用
因为每个查询对应的业务实体（即模型）不同，所以ORM映射部分不能通用

（2）公用方法封装思路

将可通用的部分封装到模板中
差异化部分（即不可通用部分），可以定义一个处理接口，以便于通过参数传入个性化的实现部分

（3）具体实现
通用分页查询模板类：

package com.zking.util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;


public final class BaseDao {
	
private BaseDao() {}
	
	//回调函数接口
	public static interface ICovent<T> {
		List<T> convent(ResultSet rs) throws SQLException;
	}
	
	public static <T> List<T> query(String sql, 
			List<Object> paramList, 
			PageBean pageBean,
			ICovent<T> covent
			) {
		
		Object[] params = paramList.toArray();
		
		List<T> students = new ArrayList<>();
		
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		
		if(pageBean == null || !pageBean.isPagination()) {
			try {
				con = DBUtil.getConection();
				ps = con.prepareStatement(sql);
				
				//设置查询参数
				int i = 1;
				for(Object param: params) {
					ps.setObject(i, param);
					i++;
				}
				
				rs = ps.executeQuery();
				
				//通过使用者传入的回调函数，执行转换
				students = covent.convent(rs);
				
			} catch (SQLException e) {
				e.printStackTrace();
			} finally {
				DBUtil.closeDB(rs, ps, con);
			}
		} else {
			//需要分页的情况
			String countSql = "select COUNT(*) from (" + sql + ") tmp";
			
			try {
				con = DBUtil.getConection();
				ps = con.prepareStatement(countSql);
				//设置查询参数
				int i = 1;
				for(Object param: params) {
					ps.setObject(i, param);
					i++;
				}
				
				rs = ps.executeQuery();
				if(rs.next()) {
					Integer total = rs.getInt(1);
					pageBean.setTotal(total);
				}
				
				//判断总记录数是否大于0，如果大于零表示有记录，需求查询当前记录
				//如果没有就直接返回
				if(pageBean.getTotal() <= 0) {
					return students;
				}
				
				//查询当前业的数据
				String pagingSql = sql + " limit " + pageBean.getStartIndex() + ", " + pageBean.getRows();
				ps = con.prepareStatement(pagingSql);
				//设置查询参数
				int j = 1;
				for(Object param: params) {
					ps.setObject(j, param);
					j++;
				}
				rs = ps.executeQuery();
				
				//变化部分
				students = covent.convent(rs);
				
			} catch (SQLException e) {
				e.printStackTrace();
			}  finally {
				DBUtil.closeDB(rs, ps, con);
			}
			
		}
		
		return students;
	}
}

将公用方法封装好后，记得把StudentDao代码修改一下

package com.zking.util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

import com.zking.model.Student;
import com.zking.util.BaseDao.ICovent;

public class StudentDao {
	
	
	public List<Student> getStudents(String sname, PageBean pageBean) {
		//构造sql语句    变化部分
		String sql = "select * from student ";
		List<Object> param = new ArrayList<>();
		if (!Objects.isNull(sname) && sname.length() > 0) {
			sql += " where sname like ?";
			param.add("%"+sname+"%");
		}
		List<Student> list = BaseDao.query(sql, param, pageBean, new ICovent<Student> () {
			
			public List<Student> convent(ResultSet rs) throws SQLException {
				List<Student> students = new ArrayList<>();
				while(rs.next()) {
					Student stu = new Student();
					stu.setSid(rs.getInt("sid"));
					stu.setSname(rs.getString("sname"));
					stu.setScore(rs.getInt("score"));
					stu.setClazz(rs.getString("class"));
					students.add(stu);
				}
				return students;
			}
			
		});
		return list;
	}
	
	
	public static void main(String[] args) {
		StudentDao dao = new StudentDao();
		List<Student> students = dao.getStudents(null, new PageBean());
		students.forEach(t-> System.out.println(t));
	}
}

分页标签

1. 准备一个Servlet

准备一个servlet用于处理请求，获取数据库中的数据，并转发到结果显示页面。

package com.zking.servlet;

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 com.zking.model.Student;
import com.zking.util.PageBean;
import com.zking.util.StudentDao;

@WebServlet("/students")
public class StudentServlet extends HttpServlet{

	private StudentDao dao = new StudentDao();
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		
		PageBean pageBean = new PageBean();
		pageBean.setRequest(req);
		
		String sname =req.getParameter("sname");
		List<Student> students = dao.getStudents(sname, pageBean);
		req.setAttribute("students", students);

		req.getRequestDispatcher("/student.jsp").forward(req, resp);
	}
	
}

2. 过滤器解决中文乱码问题

package com.zking.util;

import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * 乱码处理
 * @author zjjt
 *
 */
public class EncodingFiter implements Filter{

	private String encoding = "UTF-8";// 默认字符集

	public EncodingFiter() {
		super();
	}

	public void destroy() {
	}

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse res = (HttpServletResponse) response;

		// 中文处理必须放到 chain.doFilter(request, response)方法前面
		res.setContentType("text/html;charset=" + this.encoding);
		if (req.getMethod().equalsIgnoreCase("post")) {
			req.setCharacterEncoding(this.encoding);
		} else {
			Map map = req.getParameterMap();// 保存所有参数名=参数值(数组)的Map集合
			Set set = map.keySet();// 取出所有参数名
			Iterator it = set.iterator();
			while (it.hasNext()) {
				String name = (String) it.next();
				String[] values = (String[]) map.get(name);// 取出参数值[注：参数值为一个数组]
				for (int i = 0; i < values.length; i++) {
					values[i] = new String(values[i].getBytes("ISO-8859-1"),
							this.encoding);
				}
			}
		}

		chain.doFilter(request, response);
	}

	public void init(FilterConfig filterConfig) throws ServletException {
		String s = filterConfig.getInitParameter("encoding");// 读取web.xml文件中配置的字符集
		if (null != s && !s.trim().equals("")) {
			this.encoding = s.trim();
		}
	}

}

在web.xml（新建项目自带的xml文件）配置

<filter>
  <filter-name>encodingFiter</filter-name>
  <filter-class>com.zking.util.EncodingFiter</filter-class>
  </filter>
  <filter-mapping>
  <filter-name>encodingFiter</filter-name>
  <url-pattern>/*</url-pattern>
  </filter-mapping>

3. 加入分页功能

<%@ 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>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

	<h1>学生信息</h1>

	<form action="<%=request.getContextPath()%>/students" method="post">
		<input type="text" name="sname"> 
		<input type="submit" value="查询">
	</form>

	<table border="1" style="width: 98%;">

		<tr>
			<td>学号</td>
			<td>姓名</td>
			<td>成绩</td>
			<td>班级</td>
		</tr>

		<c:forEach items="${students}" var="student">
			<tr>
				<td>${student.sid}</td>
				<td>${student.sname}</td>
				<td>${student.score}</td>
				<td>${student.clazz}</td>
			</tr>
		</c:forEach>

	</table>

<div style="text-align: right; width:98%;">
		第${pageBean.page}页&nbsp;&nbsp;&nbsp;
		共${pageBean.total}条记录&nbsp;&nbsp;&nbsp;
		<a href="javascript: goPage(1);">首页</a>&nbsp;&nbsp;&nbsp;
		<a href="javascript: goPage(${pageBean.previousPage});">上页</a>&nbsp;&nbsp;&nbsp; 
		<a href="javascript: goPage(${pageBean.nextPage});">下页</a>&nbsp;&nbsp;&nbsp; 
		<a href="javascript: goPage(${pageBean.totalPage});">尾页</a>&nbsp;&nbsp;&nbsp;
		第<input type="text" size="2" id="pageNumber" onkeypress="toPageNumber(event,this.value)"/> 
		<a href="javascript: goPage(document.getElementById('pageNumber').value);">GO</a>
	</div>
	
	<!-- 隐藏表达，用与分页时保存查询参数 -->
	<form action="${pageBean.url}" id="pagingForm" method="post">
		<input type="hidden" name="page" value="${pageBean.page}"/>
		<!-- 先只考虑本功能的查询参数，没有考虑公用性（不同功能的参数不同） -->
		<input type="hidden" name="sname" value="<%=request.getParameter("sname")%>"/>
	</form>
	
</body>

<script>
function goPage(pageNum) {
	debugger;
	let form = document.getElementById("pagingForm");
	let lastPage = '${pageBean.totalPage}';
	if(pageNum > lastPage) pageNum = lastPage;
	if(pageNum < 1) pageNum = 1;
	form.page.value = pageNum;
	form.submit();
}

function toPageNumber(event,pn) {
	//debugger;
	if(event.keyCode ==  13) {
		let form = document.getElementById("pagingForm");
		form.page.value = pn;
		form.submit();
	}
}
</script>

</body>
</html>

目前为止，分页功能已经实现了。

但是还有几个问题：

如果其他功能需要分页，则需要复制大量代码才能重用该功能
如果系统需要修改分页工具栏的显示风格呢？

为了解决这几个问题我们需要封装分页标签。

封装分页标签

为了方便代码的复用，及可维护性，我们将分页功能封装了一个自定义标签（其实就是将原来写在页面中的代码，通过移入到自定义标签中去实现），开发自定义标签分成三步：

编写助手类
编写标签描述文件
在页面上引入标签库，并使用

编写助手类

package com.zking.tag;

import java.io.IOException;
import java.util.Map;

import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;

import com.zking.util.PageBean;

public class PagingTag extends BodyTagSupport {

	private PageBean pageBean;

	public void setPageBean(PageBean pageBean) {
		this.pageBean = pageBean;
	}
	
	
	@Override
	public int doStartTag() {
		
		JspWriter out = this.pageContext.getOut();
		
		try {
			out.println(buildHtml());
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		return SKIP_BODY;
	}
	
	
	//构造分页的页面输出
	private String buildHtml() {
		
		String pagingTool = "<div style=\"text-align: right; width:98%;\">\r\n" + 
				"		第"+pageBean.getPage()+"页&nbsp;&nbsp;&nbsp;\r\n" + 
				"		共"+pageBean.getTotal()+"条记录&nbsp;&nbsp;&nbsp;\r\n" + 
				"		<a href=\"javascript: goPage(1);\">首页</a>&nbsp;&nbsp;&nbsp;\r\n" + 
				"		<a href=\"javascript: goPage("+pageBean.getPreviousPage()+");\">上页</a>&nbsp;&nbsp;&nbsp; \r\n" + 
				"		<a href=\"javascript: goPage("+pageBean.getNextPage()+");\">下页</a>&nbsp;&nbsp;&nbsp; \r\n" + 
				"		<a href=\"javascript: goPage("+pageBean.getTotalPage()+");\">尾页</a>&nbsp;&nbsp;&nbsp;\r\n" + 
				"		第<input type=\"text\" size=\"2\" id=\"pageNumber\" onkeypress=\"toPageNumber(event,this.value)\"/> \r\n" + 
				"		<a href=\"javascript: goPage(document.getElementById('pageNumber').value);\">GO</a>\r\n" + 
				"	</div>";
		
		String hiddenForm = "<form action='" + pageBean.getUrl() + "' id=\"pagingForm\" method=\"post\">"
				+ "<input type=\"hidden\" name=\"page\" />";
		Map<String, String[]> parameterMap = pageBean.getParameterMap();
		
		//循环所有的参数，并为所有的参数生成隐藏表单
		for(Map.Entry<String, String[]> param: parameterMap.entrySet()) {
			String paramName = param.getKey();
			if("page".equals(paramName)) continue;
			String[] values = param.getValue();
			for(String val: values) {
				hiddenForm += "<input type='hidden' name='" + paramName + "' value='" + val + "'>";
			}
		}
		hiddenForm += "</form>";
		
		
		String js = "<script>\r\n" + 
				"function goPage(pageNum) {\r\n" + 
				"	debugger;\r\n" + 
				"	let form = document.getElementById(\"pagingForm\");\r\n" + 
				"	let lastPage = '"+pageBean.getTotalPage()+"';\r\n" + 
				"	if(pageNum > lastPage) pageNum = lastPage;\r\n" + 
				"	if(pageNum < 1) pageNum = 1;\r\n" + 
				"	form.page.value = pageNum;\r\n" + 
				"	form.submit();\r\n" + 
				"}\r\n" + 
				"\r\n" + 
				"function toPageNumber(event,pn) {\r\n" + 
				"	//debugger;\r\n" + 
				"	if(event.keyCode ==  13) {\r\n" + 
				"		let form = document.getElementById(\"pagingForm\");\r\n" + 
				"		form.page.value = pn;\r\n" + 
				"		form.submit();\r\n" + 
				"	}\r\n" + 
				"}\r\n" + 
				"</script>";
		
		return pagingTool+hiddenForm+js;
	}

	
}

标签库（mytag.xml）描述文件中添加paging标签

<tag>
		<name>paging</name>
		<tag-class>com.zking.tag.PagingTag</tag-class>
		<body-content>empty</body-content>
		<description>分页标签</description>
		<attribute>
			<name>pageBean</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
	</tag>

使用分页标签

首先在页面中引入标签

<%@taglib prefix="z" uri="/zking" %>

将原来的分页功能，替换为标签即可

<z:paging pageBean="${pageBean}"/>

页面的参考代码：

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

	<h1>学生信息</h1>
	
	<form action="<%=request.getContextPath()%>/students" method="post">
		<input type="text" name="sname">
		<input type="submit" value="查询">
	</form>
	
	<table border="1" style="width: 98%;">
	
		<tr>
			<td>学号</td>
			<td>姓名</td>
			<td>年龄</td>
			<td>备注</td>
		</tr>
		
		<c:forEach items="${students}" var="student">
			<tr>
				<td>${student.sid}</td>
				<td>${student.sname}</td>
				<td>${student.score}</td>
				<td>${student.clazz}</td>
			</tr>
		</c:forEach>
		
	</table>
	
	<z:paging pageBean="${pageBean}"/>
</body>


</html>

运行结果:

通用分页功能

分页信息实体（PageBean）

后台分页数据查询

1. 处理流程

2. 实现

重构-提取公用方法

分页标签

1. 准备一个Servlet

2. 过滤器解决中文乱码问题

3. 加入分页功能

封装分页标签

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