JSP分页BEAN封装［原创］

周未在家整理了一下JSP中的分页BEAN。加上数据库连接池
［在我的博客：http://blog.chinaunix.net/u2/84280/showart.php?id=2216913直接复制代码就行］
现在分享代码：
PageBean.java

package cn.ty.bean;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.*;
import cn.ty.tools.*;
/**
 * @author [e-mail]
 * @version 1.0
 * 通用的MYSQL分页BEAN
 * */
public class PageBean {
    private int currentpage = 1;
    private int totalPages = 0;
    private String sqlConditions = "";    //查询的SQL条件

    private int percentRecords = 1;        //每页的记录数

    private boolean hasNextPage = false; //是否有下一页

    private boolean hasPreviousPage = false; //是否有前一页

    private Statement statmeStatement;
    private Connection connection;
    private String tableName;
    private String fieldName;
    private String fileName;
    private int recordCount;
    private static ConnectionPool connPool;


//如果不是静态的话就每一个对象过来都得再重新创建!!非常重要的一点切记！   
    public int getCurrentpage() {
        return currentpage;
    }
    public void setCurrentpage(int currentpage) {
        this.currentpage = currentpage;
    }
    public int getTotalPages() {
        return totalPages;
    }
    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }
    public String getSqlConditions() {
        return sqlConditions;
    }
    public void setSqlConditions(String sqlConditions) {
        this.sqlConditions = sqlConditions;
    }
    public int getPercentRecords() {
        return percentRecords;
    }
    public void setPercentRecords(int percentRecords) {
        this.percentRecords = percentRecords;
    }
    public boolean isHasNextPage() {
        return hasNextPage;
    }
    public void setHasNextPage(boolean hasNextPage) {
        this.hasNextPage = hasNextPage;
    }
    public boolean isHasPreviousPage() {
        return hasPreviousPage;
    }
    public void setHasPreviousPage(boolean hasPreviousPage) {
        this.hasPreviousPage = hasPreviousPage;
    }
    public String getTableName() {
        return tableName;
    }
    public void setTableName(String tableName) {
        this.tableName = tableName;
    }
    public String getFieldName() {
        return fieldName;
    }
    public void setFieldName(String fieldName) {
        this.fieldName = fieldName;
    }
    public String getFileName() {
        return fileName;
    }
    public void setFileName(String fileName) {
        this.fileName = fileName;
    }
    public int getRecordCount() {
        return recordCount;
    }
    public void setRecordCount(int recordCount) {
        this.recordCount = recordCount;
    }
    public PageBean(){
        
    }
    public void init() {
        if (connPool == null) {
            connPool = new ConnectionPool("com.mysql.jdbc.Driver","jdbc:mysql://localhost:3306/cublog","root","123");
            try {
                connPool.setInitialConnections(10);
                connPool.setMaxConnections(50);
                connPool.createPool();
                this.connection = connPool.getConnection();
                this.statmeStatement = this.connection.createStatement();
            } catch (Exception e) {
                System.out.println(e.toString());
            }
        } else {

        //如果连接池对象已经创建了就直接使用了。
            try {
                this.connection = connPool.getConnection();
                this.statmeStatement = this.connection.createStatement();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            
        }
        
    }
    /**
     * @see: 计算出来总的页面
     * */
    private void getTotalPage() {
        ResultSet rSet = null;
        String sqlString = "select count(*) as total from " + tableName + " where " + sqlConditions;
        try {
            rSet = this.statmeStatement.executeQuery(sqlString);
            while(rSet.next()) recordCount = Integer.parseInt(rSet.getString("total"));
            if ((recordCount % this.percentRecords) == 0) {
     totalPages = recordCount / this.percentRecords;
     } else {
     totalPages = recordCount / this.percentRecords + 1;
     }
            //判断是否有下一页

     if (currentpage >= totalPages) {
     hasNextPage = false;
     } else {
     hasNextPage = true;
     }
     //判断是否有前一页

     if ((currentpage - 1) > 0) {
     hasPreviousPage = true;
     } else {
     hasPreviousPage = false;
     }
            
        } catch (SQLException e) {
            // TODO Auto-generated catch block

            e.printStackTrace();
        } finally {
            rSet = null;
        }
    }
    /**
     * 计算当前所传入的字段、条件、表名、页数返回当前页的记录集.记录集合
     * */
    public List getCurrPageRecords() {
        ResultSet rs = null;
        List list = new ArrayList();
        StringBuffer tmp = new StringBuffer();

        if(currentpage < 1) {
            return list;    //注意如果记录集为0的话这个为小于1的数字的可能
        }
        int limit = (currentpage - 1) * percentRecords;
        tmp.append("select ");
        tmp.append(fieldName);
        tmp.append(" from ");
        tmp.append(tableName);
        tmp.append(" where ");
        tmp.append(sqlConditions);
        tmp.append(" limit " + String.valueOf(limit) + "," + percentRecords);
        String sqlString = tmp.toString();
        try {
            rs = this.statmeStatement.executeQuery(sqlString);
            list = convertList(rs);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return list;
        
    }
    /**
     * 将ResultSet转换成List封装
     * */
    private List convertList(ResultSet rs) throws SQLException {
         List list = new ArrayList();
         ResultSetMetaData md = rs.getMetaData();
         int columnCount = md.getColumnCount();
         while (rs.next()) {
             Map rowData = new HashMap();
             for (int i = 1; i <= columnCount; i++) {
                 rowData.put(md.getColumnName(i), rs.getObject(i));
             }
             list.add(rowData);
         }
         return list;
    }
    
    /**
     * 显示分页的条目 第一页..
     * */
   public String showPages() {
     getTotalPage();
     StringBuffer tmp = new StringBuffer();
     tmp.append("共有文章"+String.valueOf(recordCount) + "篇");
     tmp.append("第("+currentpage+"/"+totalPages+") ");
     tmp.append("首页  ");
    
     if (hasPreviousPage){
         int prepage = currentpage - 1;
         tmp.append("上一页  ");
        
     }
     else
         tmp.append("上一页  ");
     tmp.append("1 ");
     tmp.append("2 ");
     tmp.append("3 ");
     tmp.append("4 ");
     tmp.append("5 ..");
     if (hasNextPage){
         int prepage = currentpage + 1;
         tmp.append("下一页  ");
     }
     else
         tmp.append("下一页  ");
     tmp.append("未页  ");
     return tmp.toString();
   }
   /**
    * 显示将数据库连接对象回收!记得要回收资源
    * */
  public void resetDB() {
     connPool.returnConnection(this.connection);
     this.connection = null;
     this.statmeStatement = null;
  }
}

以上就是分页的BEAN了。调用的JSP showCU.jsp 如下：

");
}
%>
</table>
<div>
<%
out.print(pagebean.showPages());//内容主体
%>
</div>
</body>
</html>
<%
resultSet =null;
pagebean.resetDB();  //记得将当前页面的开了的资源关闭掉
%>

<%@ page language="java" import="java.util.*;" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <jsp:useBean id="pagebean" scope="request" class="cn.ty.bean.PageBean" beanName="cn.ty.bean.PageBean"/> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" ""> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> <style type="text/css"> A:link {text-decoration: none} A:visited {text-decoration: none} A:active {text-decoration: none} A:hover {font-size:24; font-weight:bold; color: red;} </style> </head> <body> <jsp:setProperty name="pagebean" property="currentpage"/> <table border='1'> <tr> <td>ID</td> <td>标题</td> </tr> <% int currpage = 1; try {     currpage = Integer.parseInt(request.getParameter("page")); } catch(Exception e) {     currpage = 1; } pagebean.setSqlConditions("1=1"); pagebean.setPercentRecords(10); pagebean.setFieldName("id,title"); pagebean.setFileName("showCU.jsp"); pagebean.setTableName("cu_blog_page"); pagebean.setCurrentpage(currpage); pagebean.init(); List resultSet = pagebean.getCurrPageRecords(); Map rowData = new HashMap(); for (Iterator i = resultSet.iterator(); i.hasNext();) {    rowData = (Map)i.next();    out.print("

" + String.valueOf(rowData.get("id")) + "

" + rowData.get("title") + "

OK！分页BEAN以后就直接使用这个代码就行了。

原创文章～～～如果大家发现问题请联系我。