jsp+servlet+javabean （MVC）分页



最近遇到了分页的问题，以前说真的没仔细研究过了，这几天仔细高了一下，基本原理高清楚了，上次我发了一个jsp的分页程序了，其实那个还有很多地方完善，这两天总结了一下，用MVC摸式改进了一下，还是强调一点我一直都觉的JSP不要在页面写代码，因为影响分工了，所以我一直在编程都努力的在做了，但是这些代码我只是完成了功能，还有代码优化的地方，我没去做，这个批评一下自己了，不过因为最近真的好多事了，说真的由于我的电脑硬盘坏了，好多东西我都从头来学，真的好郁闷了，其实这些我以前都做出来了，但是电脑挂了，没办法了，从头来啊！不乱砍了，首先是我的页面代码如下：

<%@ page language=”java” import=”java.util.*,java.sql.*” pageEncoding=”gb2312″%> <%@taglib uri=”http://java.sun.com/jsp/jstl/core” prefix=”c”%> <html> <head> </head> <body> <form action=”#”>    <c:forEach items=”${news1}” var=”news2″ varStatus=”status”>         <tr><td>${news2.newsTitle}</td>            </tr>   </c:forEach>        <c:if test=”${showpage>1}”>               <a href=”pageservlet?topage=<%=1%>”>首页</a>               <a href=”pageservlet?topage=${showpage-1}”>上一页</a>               </c:if>                <c:if test=”${showpage<pagecount}”>               <a href=”pageservlet?topage=${showpage+1}”>下一页</a>               <a href=”pageservlet?topage=${pagecount}”>最后一页</a>               </c:if>               第${showpage}页               一共${pagecount}页 </form> <br> </body> </html> servlet代码如下：

package org.servlet;

import java.util.ArrayList;

import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;

import org.util.ContactBean; import org.util.PageBean;

public class PageServlet extends javax.servlet.http.HttpServlet {

public void doGet(HttpServletRequest

request, HttpServletResponse response)    throws javax.servlet.ServletException, java.io.IOException {   response.setContentType(“text/html”);   try {    PageBean pagebean = new PageBean();    ContactBean contact = new ContactBean();    int pagecount = pagebean.countPage();//获取总共的页数    String topage = request.getParameter(“topage”);//获取当前的页码    if (Integer.parseInt(topage) > pagecount) {  //判断当前的页码是否越界,如果是的话就进行处理     topage =String.valueOf(pagecount);    } else if (Integer.parseInt(topage) <= 0) {     topage = “1″;    }    ArrayList news = contact.getData(topage, pagecount);    request.getSession().setAttribute(“pagecount”, pagecount);    request.getSession().setAttribute(“showpage”, topage);//将当前的页码返回给页面,这样进行计算    request.getSession().setAttribute(“news1″, news);    response.sendRedirect(“test1.jsp”);   } catch (Exception e) {    e.printStackTrace();   }

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws javax.servlet.ServletException, java.io.IOException {   doGet(request, response); } }

javabean代码如下：


package org.util;

import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; import java.util.Vector;

import org.bean.NewsBean;

public class ContactBean { private Connection conn; public Connection getConnection() {   try {    Class.forName(“com.mysql.jdbc.Driver”);    conn = DriverManager      .getConnection(        “jdbc:mysql://localhost/test?useUnicode=true&amp;characterEncoding=gbk”,        “root”, “123456″);   } catch (SQLException ex) {    System.out.println(ex.getMessage() + “路径错误”);   } catch (ClassNotFoundException ex) {    System.out.println(ex.getMessage() + “驱动错误”);   }   return conn; }

/** *返回要查询的记录数 */ public int getAvailableCount() throws Exception {   int ret = 0;   String strSql = “select count(*) from news”;   Connection conn = this.getConnection();   Statement stmt = conn.createStatement();   ResultSet rset = stmt.executeQuery(strSql);   while (rset.next()) {    ret = rset.getInt(1);   }   return ret; }     /*获取查寻的记录数*/ public ArrayList getData(String topage, int pagecount)    throws NumberFormatException, SQLException {   String sql = “select * from news”;   Statement state = null;   ResultSet rs = null;   int pagesize = 3;   int showpage = 1;   ArrayList list = new ArrayList();   int j = 0;   try {    Connection conn = this.getConnection();    state = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,      ResultSet.CONCUR_READ_ONLY);    rs = state.executeQuery(sql);   } catch (Exception e) {    System.out.println(“exception”);   }   if (!rs.next()) {    System.out.println(“no records!”);   } else {    rs.last();    if (topage != null) {     showpage = Integer.parseInt(topage);     if (showpage > pagecount) {      showpage = pagecount;     } else if (showpage <= 0) {      showpage = 1;     }    }    rs.absolute((showpage – 1) * pagesize + 1);    for (int i = 1; i <= pagesize; i++) {     NewsBean news = new NewsBean();     news.setNewsContent(rs.getString(2));     news.setNewsTitle(rs.getString(3));     list.add(j, news);     ++j;     if (!rs.next())      break;    }

}   return list; }

}

package org.util;

public class PageBean { public int maxPage; // 一共有多少页 public int maxRowCount; // 一共有多少行 public int pagesize = 3; // 每页多少行 public PageBean() { }

public int countPage() throws Exception { int maxRowCount=this.MaxCount();   if (maxRowCount % this.pagesize == 0) {    maxPage = maxRowCount / this.pagesize;   } else {    maxPage =maxRowCount/ this.pagesize + 1;   }   return maxPage; }

public int MaxCount() throws Exception {   ContactBean contact=new ContactBean();   this.maxRowCount = contact.getAvailableCount(); // 得到总行数         return maxRowCount; }

} 其实这两个JAVABEAN可以写成一个了，并且很多代码可以提出来，做成一个复用性强的代码了，这里我结合我这几天上网查资料的感受，那些分页多半是只能作者能用了，读者就用不了。所以我这里写了全部代码了，也不知道别人看不看的懂了！

http://blog.csdn.net/xiaolu123456789/article/details/3500856