jsp通用分页【一】

1. PageBean

package com.zyp.util;

/**
 *
 * 分页工具类
 */
public class PageBean {

	private int page = 1;// 页码

	private int rows = 10;// 页大小

	private int total = 0;// 总记录数

	private boolean pagination = true;// 是否分页

	public PageBean() {
		super();
	}

	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 void setTotal(String total) {
		this.total = Integer.parseInt(total);
	}

	public boolean isPagination() {
		return pagination;
	}

	public void setPagination(boolean pagination) {
		this.pagination = pagination;
	}

	/**
	 * 获得起始记录的下标
	 * 
	 * @return
	 */
	public int getStartIndex() {
		return (this.page - 1) * this.rows;
	}

	@Override
	public String toString() {
		return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + "]";
	}

}

2、BaseDao

package com.zyp.util;

import java.lang.reflect.Field;
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 com.zyp.entity.Book;

/**
 * T = Book.class
 * T = Student.class
 * @author zhouyanpeng
 *
 * @param <T>
 */
public class BaseDao<T> {
	/**
	 * 
	 * @param sql	决定查询哪张表的数据
	 * @param clz	查询出来的数据封装到哪个实体类中
	 * @param pagebean	决定是否分页
	 * @return
	 * @throws IllegalAccessException 
	 * @throws InstantiationException 
	 * @throws SQLException 
	 */
	public List<T> executeQuery(String sql,Class clz,PageBean pagebean) throws InstantiationException, IllegalAccessException, SQLException{
		List<T> list = new ArrayList<>();
		Connection con = DBAccess.getConnection();
		PreparedStatement pst = null;
		ResultSet rs = null;
		if(pagebean != null && pagebean.isPagination()) {
			//该分页了
			String countSql = getCountSql(sql);
			pst = con.prepareStatement(countSql);
			rs = pst.executeQuery();
			if(rs.next()) {
				pagebean.setTotal(rs.getLong(1)+"");
			}
			
			String pageSql = getpageSql(sql,pagebean);
			pst = con.prepareStatement(pageSql);
			rs = pst.executeQuery();
		}else {
			pst = con.prepareStatement(sql);
			rs = pst.executeQuery();
		}
		try {
			while (rs.next()) {
				//			list.add(new Book(rs.getInt("bid"), rs.getString("bname"), rs.getFloat("price")));
				/**
				 * 这行代码干的事
				 * 1、创建了一个Book对象
				 * 2、从ResultSet结果集中获取值放入Book对象中属性中
				 * 	2.1	获取Book的属性对象
				 * 	2.2	给属性对象赋值
				 * 3、将已经有值的Book对象放入List集合中
				 */
				T t = (T) clz.newInstance();
				Field[] Fields = clz.getDeclaredFields();
				for (Field field : Fields) {
					field.setAccessible(true);
					field.set(t, rs.getObject(field.getName()));//第二步完成
				}	
				list.add(t);
			} 
		} finally {
			//shift+alt+z
			DBAccess.close(con, pst, rs);;
		}
		return list;
	}

	/**
	 * 将原生sql拼接出符合条件的某一页的数据查询sql
	 * @param sql
	 * @param pagebean
	 * @return
	 */
	private String getpageSql(String sql, PageBean pagebean) {
		// TODO Auto-generated method stub
		return sql+" limit" +pagebean.getStartIndex()+","+pagebean.getRows();
	}


	/**
	 * 用原生sql拼接出查询符合条件的记录数。
	 * @param sql
	 * @return
	 */
	private String getCountSql(String sql) {
		// TODO Auto-generated method stub
		return "select count(1) from ("+sql+") t";
	}
}

3、案例演示【book】

实例化Book类

package com.zyp.entity;

public class Book {
	private int bid;
	private String bname;
	private float price;

	@Override
	public String toString() {
		return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
	}

	public int getBid() {
		return bid;
	}

	public void setBid(int bid) {
		this.bid = bid;
	}

	public String getBname() {
		return bname;
	}

	public void setBname(String bname) {
		this.bname = bname;
	}

	public float getPrice() {
		return price;
	}

	public void setPrice(float price) {
		this.price = price;
	}
	
	public Book() {
		super();
	}
	public Book(int bid, String bname, float price) {
		super();
		this.bid = bid;
		this.bname = bname;
		this.price = price;
	}
	
}

BookDao

package com.zyp.dao;

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 com.zyp.entity.Book;
import com.zyp.util.BaseDao;
import com.zyp.util.DBAccess;
import com.zyp.util.PageBean;
import com.zyp.util.StringUtils;

/**
 * 操作数据库中的t_mvc_book表
 * 1、加载驱动
 * 2、建立连接
 * 3、获取预定义处理对象
 * 4、执行sql语句
 * 5、处理结果集
 * 6、关闭连接
 * @author zhouyanpeng
 *
 */
public class BookDao extends BaseDao<Book>{
	
//	/**
//	 * 
//	 * @param book 是从jsp传递过来的参数封装成对象作为参数查询并执行的sql
//	 * @return pageBean  决定是否分页
//	 * @throws SQLException 
//	 */
//	public List<Book> list(Book book,PageBean pagebean) throws SQLException{
//		List<Book> list = new ArrayList<>();
//		String sql = "select * from t_mvc_book where 1 = 1";
//		if(StringUtils.isNotBlank(book.getBname())) {
//			sql += " and bname like '%"+book.getBname()+"%'";
//		}
//		Connection con = DBAccess.getConnection();
//		PreparedStatement pst = con.prepareStatement(sql);
//		ResultSet rs = pst.executeQuery();
//		while(rs.next()) {
//			list.add(new Book(rs.getInt("bid"), rs.getString("bname"), rs.getFloat("price")));
//		}
//		return list;
//	}
//	public static void main(String[] args) throws SQLException {
//		BookDao bookdao = new BookDao();
//		Book b = new Book();
//		List<Book> list = bookdao.list(b, null);
//		for (Book book : list) {
//			System.out.println(book);
//		}
//	}
	
	/**
	 * 
	 * @param book 是从jsp传递过来的参数封装成对象作为参数查询并执行的sql
	 * @return pageBean  决定是否分页
	 * @throws SQLException 
	 * @throws IllegalAccessException 
	 * @throws InstantiationException 
	 */
	public List<Book> list(Book book,PageBean pagebean) throws SQLException, InstantiationException, IllegalAccessException{
		String sql = "select * from t_mvc_book where 1=1";
		if(StringUtils.isNotBlank(book.getBname())) {
			sql += " and bname like '%"+book.getBname()+"%'";
		}
		return super.executeQuery(sql, Book.class, pagebean);
	}
	public static void main(String[] args) {
		BookDao bookdao = new BookDao();
		try {
			Book b = new Book();
			PageBean pageBean = new PageBean();
//			pageBean.setPage(2);
			pageBean.setPagination(false);
			b.setBname("圣墟");
			List<Book> list = bookdao.list(b, pageBean);
			for (Book book : list) {
				System.out.println(book);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InstantiationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
	
}

测试结果

public static void main(String[] args) {
		BookDao bookdao = new BookDao();
		try {
			Book b = new Book();
			PageBean pageBean = new PageBean();
			pageBean.setPage(2);//第几页 2
//			pageBean.setPagination(false);//不分页
			b.setBname("圣墟");//模糊查询的参数
			List<Book> list = bookdao.list(b, pageBean);
			for (Book book : list) {//遍历输出
				System.out.println(book);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InstantiationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

打印结果
在这里插入图片描述
分页三要素
1、 page: 页码 视图层传递过来
2、rows: 页大小 视图层传递过来
3、total : 总记录数 后台查出来

想要了解更多,联系博主。

自己收集的jsp分页代码。对于北大青鸟Y2的学员可能有用吧。自己也在做这个项目。这里有增、删、该、查加分页。有上页、下页、首页、尾页、第几页、还有带数字和点的分页。可以说是非常好的分页代码。想要的朋友自己处下载 <%@ page contentType="text/html; charset=GB2312" language="java" import="java.sql.*" errorPage="" %> <%@ page import="java.io.*" %> <%@ page import="java.util.*" %> <% java.sql.Connection sqlCon; //数据库连接对象 java.sql.Statement sqlStmt; //SQL语句对象 ResultSet sqlRst=null; //java.sql.ResultSet sqlRst; //结果集对象 java.lang.String strCon; //数据库连接字符串 java.lang.String strSQL; //SQL语句 int intPageSize; //页显示的记录数 int intRowCount; //记录总数 int intPageCount; //总页数 int intPage; //待显示页码 java.lang.String strPage; int i; //设置页显示的记录数 intPageSize = 2; //取得待显示页码 strPage = request.getParameter("page"); if(strPage==null){ //表明在QueryString中没有page这个参数,此时显示第页数据 intPage = 1; } else{ //将字符串转换成整型 intPage = java.lang.Integer.parseInt(strPage); if(intPage<1) intPage = 1; } %><% String DBUser="sa"; String DBPassword="88029712"; //String DBServer="127.0.0.1"zjprice; String DBUrl="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=pubs"; //创建语句对象 //Class.forName("org.gjt.mm.mysql.Driver").newInstance(); Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance(); sqlCon=java.sql.DriverManager.getConnection(DBUrl,DBUser,DBPassword); sqlStmt=sqlCon.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY); //执行SQL语句并获取结果集 String sql=null; String search=""; String ToPage=request.getParameter("ToPage"); if(request.getParameter("search")!=null &&!request.getParameter("search").equals("")) {search=new String(request.getParameter("search").trim().getBytes("8859_1")); } sql="select top 50 au_id,au_lname from authors "; /*sql="select*from ta,tb where id like'%"+search+"%'"; sql=sql+"or title like'%"+search+"%'"; sql=sql+"or time like'%"+search+"%'"; sql=sql+"or con like'%"+search+"%'"; sql=sql+"order by id";*/ sqlRst=sqlStmt.executeQuery(sql); //获取记录总数 sqlRst.last(); intRowCount = sqlRst.getRow(); //记算总页数 intPageCount = (intRowCount+intPageSize-1) / intPageSize; //调整待显示的页码 if(intPage>intPageCount) intPage = intPageCount; %> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312"> <title>test</title> </head> <body> <table border="1" cellspacing="0" cellpadding="0"> <tr> <th>标题id</th> <th>内容表</th> </tr> <% if(intPageCount>0) { //将记录指针定位到待显示页的第条记录上 sqlRst.absolute((intPage-1) * intPageSize + 1); //显示数据 i = 0; while(i<intPageSize && !sqlRst.isAfterLast()){ %> <tr> <td> <%=sqlRst.getString(1)%> </td> <td> <%=sqlRst.getString(2)%> </td> </tr> <% sqlRst.next(); i++; } } %> <tr><td colspan="8">共有<font color=red><%= intRowCount %></font>条记录 当前<font color=red><%=intPage%>/<%=intPageCount%></font>页  <% if(intPageCount > 1){ %> <% if(intPage !=0){%> <a href="mysqlpage.jsp">首页</a> <%}if(intPage != 1){%><a href="mysqlpage.jsp?page=<%= intPage - 1 %>">上页</a> <%}if(intPage<intPageCount){%><a href="mysqlpage.jsp?page=<%=intPage+1%>">下页</a><%}%> <a href="mysqlpage.jsp?page=<%= intPageCount %>">尾页</a> <% } %>跳转到 <select name="page" onChange="javascript:this.form.submit();"> <% for(i=1;i<=intPageCount;i++){%> <option value="<%= i %>" <% if(intPage == i){%>selected<% } %>><%= i %></option> <% } %> </select>页 <%int m,n,p; %> <%if (intPage>1){ if(intPage-2>0){ m=intPage-2;} else { m=1;} if(intPage+2<intPageCount){ n=intPage+2;} else{ n=intPageCount; }%> 转到页码: [ <% for(p=m;p<=n;p++) { if (intPage==p){ %> <font color="black"><%=p %></font> <% } else{%> <a href=?page=<%=p %>><font color=red>[<%=p %>]</font></a> <% } }%>]<%} %> </td></tr> </table> </body> </html> <% //关闭结果集 sqlRst.close(); //关闭SQL语句对象 sqlStmt.close(); //关闭数据库 sqlCon.close(); %>
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