Javaweb compiling paging MySQL

1. Package Pagebean

Import java.util.list;/** * Pagination of JavaBean * @author Administrator */public class Pagebean<t> {//current page private in    T Pagecode;    Total pages//private int totalpage;    Total record number private int totalcount;    Number of record bars per page private int pageSize;    Data displayed per page private list<t> beanlist;    public int Getpagecode () {return pagecode;    } public void Setpagecode (int pagecode) {this.pagecode = Pagecode; }/** * Call Gettotalpage () to get to the total number of pages * JavaBean Property rules: Totalpage is JavaBean is attribute ${pagebean.totalpage} * @return *        /public int gettotalpage () {//calculate int totalpage = totalcount/pagesize;        Description divisible if (totalcount% pageSize = = 0) {return totalpage;        }else{return totalpage + 1;    }}/*public void Settotalpage (int totalpage) {this.totalpage = Totalpage;    }*/public int Gettotalcount () {return totalcount;     } public void Settotalcount (int totalcount) {   This.totalcount = TotalCount;    } 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; }}

2.Servlet

/**     * 获取当前页     *如果用户没有传，默认是第一页，如果传了，就是几     * @param request     * @return     */    public int getPageCode(HttpServletRequest request){        String pc = request.getParameter("pc");        // 判断        if(pc == null || pc.trim().isEmpty()){            return 1;        }        return Integer.parseInt(pc);    }

/**     * 分页查询     */    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        /**         * 处理当前页         * 处理每页显示的记录条数         */        // 当前页        int pageCode = getPageCode(request);        // 处理每页显示的记录条数        int pageSize = 4;        try {            // 调用业务层，分页查询            PageBean<Product> page = new ProductService().findByPage(pageCode,pageSize);            // 存入            request.setAttribute("page", page);            // 转发            request.getRequestDispatcher("/jsp/pages.jsp").forward(request, response);        } catch (SQLException e) {            e.printStackTrace();        }    }

3.service

/**     * 分页查询     * @param pageCode     * @param pageSize     * @return     * @throws SQLException      */    public PageBean<Product> findByPage(int pageCode, int pageSize) throws SQLException {        return new ProductDao().findByPage(pageCode,pageSize);    }

4.dao

/**     * 分页查询     *      * @param pageCode     * @param pageSize     * @return     * @throws SQLException      */    public PageBean<Product> findByPage(int pageCode, int pageSize) throws SQLException {        PageBean<Product> page = new PageBean<>();        // 属性是空的        page.setPageCode(pageCode);        page.setPageSize(pageSize);        QueryRunner qr = new QueryRunner(JdbcUtils.getDataSource());        // ScalarHandler 处理聚合函数        long count = (long) qr.query("select count(*) from product", new ScalarHandler());        // 设置总记录条数        page.setTotalCount((int) count);        // limit a,b a = (当前页-1) * b        List<Product> beanList = qr.query("select * from product limit ?,?", new BeanListHandler<Product>(Product.class),                (pageCode - 1) * pageSize, pageSize);        // 每页显示的数据        page.setBeanList(beanList);        return page;    }

5.utils

public class Jdbcutils {///member variable, created C3P0 connection pool (connection pool already exists ...    private static final Combopooleddatasource DATASOURCE = new Combopooleddatasource ();    /** * Returns the C3P0 connection pool * @return */public static DataSource Getdatasource () {return DataSource;        /** * Gets the connection, returns the connection * @return */public static Connection getconnection () {Connection conn = null;        try {//From the connection pool to get the connection, Conn is the enhanced connection conn = Datasource.getconnection ();        } catch (SQLException e) {e.printstacktrace ();    } return conn; /** * Release Resources * @param stmt * @param conn * * public static void release (Statement stmt,connection con            N) {if (stmt! = null) {try {stmt.close ();            } catch (SQLException e) {e.printstacktrace ();            }} if (conn! = null) {try {//has become returned ... conn.close (); } CatCH (SQLException e) {e.printstacktrace (); }}}/** * Free resources * @param stmt * @param conn * * public static void release (ResultSet rs,st            Atement Stmt,connection conn) {if (rs! = null) {try {rs.close ();            } catch (SQLException e) {e.printstacktrace ();            }} if (stmt! = null) {try {stmt.close ();            } catch (SQLException e) {e.printstacktrace ();                }} if (conn! = null) {try {//has modified the close (), it was destroyed, and now the method becomes the return connection.            Conn.close ();            } catch (SQLException e) {e.printstacktrace (); }        }    }}

6.jsp page

<table border= "1" width= "100%" > <tr> <th> serial number </th> <th> pictures </th> &    Lt;th> name </th> <th> Market price </th> <th> Mall Price </th> <th> Product Date </th>            </tr> <c:foreach var= "P" items= "${page.beanlist}" varstatus= "vs" > <tr align= "Center" > <td>${vs.count}</td> <td>  </td> <td>${p.pname}</td> <td>${p.market_price}</td> <td>${p.shop_price}</td> <td&gt            ; ${p.pdate}</td> </tr> </c:forEach> pagination <tr> <th colspan= "6" > Section ${Page.pagecode} page/Total ${page.totalpage} page <a href= "${PageContext.request.contextPath}/findbypage?p    C=1 "> Home </a>        <c:if test= "${page.pagecode > 1}" > <a href= "${PageContext.request.contextPath}/find                BYPAGE?PC=${PAGE.PAGECODE-1} "> Previous </a> </c:if> begin and end values are variable, set begin and end values Logic: * If the total number of Pages <=10 page, let begin=1 end= total pages * If total pages > 10 pages, begin= current page -5, end = Current page + 4 * head overflow: If begin<1, there is a head overflow, let begin=1 end=10 * tail Overflow: If End > Total pages, let beg                    in= Total Pages-9 end= total pages <c:choose> <c:when test= "${page.totalpage <=" >                <c:set var= "Begin" value= "1"/> <c:set var= "End" value= "${page.totalpage}"/> </c:when> <c:otherwise> <c:set var= "Begin" Value= "${Page.pagec                     ode-5} "/> <c:set var=" End "value=" ${Page.pagecode + 4} "/> Header overflow problem <c:if Test= "${begin < 1}" > <c:set var= "Begin" value= "1"/> <c:set var=                         "End" value= "/> </c:if> <c:if test=" ${End > Page.totalpage} "> <c:set var= "Begin" Value= "${page.totalpage-9}"/> <c:set var= "E nd "value=" ${page.totalpage} "/> </c:if> </c:otherwise> </ c:choose> <c:foreach var= "i" begin= "${begin}" end= "${End" > <a href= "${Pagecont Ext.request.contextPath}/findbypage?pc=${i} ">[${I}]</a> </c:forEach> <c:if test = "${Page.pagecode < Page.totalpage}" > <a href= "${PageContext.request.contextPath}/findbypage?p C=${page.pagecode + 1} "> Next </a> </c:if> <a href=" ${pageContext.request.contextPat H}/findbypage?pc=${page. Totalpage} "> Last </a> </th> </tr></table> 

Javaweb paging MySQL