Jsp的分页操作源代码

最新推荐文章于 2021-01-19 23:54:20 发布

原创最新推荐文章于 2021-01-19 23:54:20 发布 · 430 阅读

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文章标签：

#jsp #string #数据库 #list #dao #servlet

Jsp的分页操作源代码

一分页操作的分析：

1．层的问题

Com.csdn.domaim

Com.csdn.dao

Com.csdn.daoImpl

Com.csdn.service 接口

Com.csdn.serviceImpl 实现类

Com.csdn.web 控制器

Com.csdn.web.filter

Com.csdn.web.listener

Com.csdn.util

2．如何实现的问题

StuentBean中定义了几个私有的属性： id name age address

StudentDao接口用于实现对数据库中属性的封装。

StudntService接口：定义方法，用数据库处理的方法

StudentServicImpl实现类

ControllerService：控制器：接收客户端的请求

List.jsp 显示所有的信息

3．分页显示：

首先先检查是否与数据库连接，可以先把所有的都输出。

然后要点击浏览器中的超链接来获取从数据库中读取的数据并显示，在超链接的时候要传参数，通过对servlet层的访问，在servlet层中对从数据库中的数据进行读取之后，通过判断再把参数传给浏览器并显示从数据库中调用的数据

二代码的实现和说明

1．首先创建数据库，如图：

并从数据库中插入数据

2．在java中把数据库中的数据封装成类 StudentBean.java

publicclass StudentBean {

privateint id;

private String name;

privateint age;

private String address;

public StudentBean() {

super();

// TODO Auto-generated constructor stub

}

public StudentBean(int id, String name, int age, String address) {

super();

this.id = id;

this.name = name;

this.age = age;

this.address = address;

}

publicint getId() {

return id;

}

publicvoid setId(int id) {

this.id = id;

}

public String getName() {

return name;

}

publicvoid setName(String name) {

this.name = name;

}

publicint getAge() {

return age;

}

publicvoid setAge(int age){

this.age = age;

}

public String getAddress() {

return address;

}

publicvoid setAddress(String address) {

this.address = address;

}

@Override

public String toString() {

return "StudentBean [address=" + address + ", age=" + age +", id="

+ id + ", name=" + name + "]";

}

3.创建实现对数据库数据的查找和分页的查找，首先先创建一个dao层，并在dao层写上一个接口和一个daoImpl两个java类，接口是为了在service层中与servetl成的连接，首先创建StudentDao.java

import java.util.List;

import com.hbsi.domain.StudentBean;

public interface StudentDao {

//返回所有记录行

public List<StudentBean> findAll();

//返回指定页中显示的记录行（一共有多少页，共多长）

public List<StudentBean> listPage(intcurrentPage,int pageSize);

//返回所有记录的行数

public int getSize();

}

再创建实现类 StudentDaoImpl.java

package com.hbsi.dao;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.LinkedList;

import java.util.List;

import com.hbsi.domain.StudentBean;

//接口的实现类

public class StudentDaoImpl implements StudentDao {

//声明操作的数据库对象

private static Connection conn;

private PreparedStatement pstmt;

private ResultSet rs;

//第一步：准备驱动程序，构造到项目路径中

private static final StringURL="jdbc:mysql://localhost:3306/demo?user=root&password=qiao&useUnicode=true&characterEncoding=utf8";

static{

try {

//第二步：加载驱动程序

Class.forName("com.mysql.jdbc.Driver");

//第三步:获取连接对象

conn = DriverManager.getConnection(URL);

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

private int size;//记录多少行

public List<StudentBean> findAll() {

//存放读取的数据

List<StudentBean> list = newLinkedList<StudentBean>();

try {

pstmt = conn.prepareStatement("select * fromstudent");

rs = pstmt.executeQuery();

//从结果集中读取

while(rs.next()){

StudentBean s = new StudentBean();

s.setId(rs.getInt(1));

s.setName(rs.getString(2));

s.setAge(rs.getInt(3));

s.setAddress(rs.getString(4));

list.add(s);

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

size=list.size();

return list;

}

//获取总的记录行数

public int getSize() {

// TODO Auto-generated method stub

findAll();

return size;

}

//截取的读取

public List<StudentBean> listPage(int currentPage,int pageSize) {

//存放读取的数据

List<StudentBean> list = newLinkedList<StudentBean>();

try {

//记录行

int recordIndex=(currentPage-1)*pageSize;

pstmt = conn.prepareStatement("select * from studentlimit ?,?");

int index =1;

pstmt.setInt(index++, recordIndex);

pstmt.setInt(index++, pageSize);

//从结果集中读

rs = pstmt.executeQuery();

while(rs.next()){

StudentBean s = new StudentBean();

s.setId(rs.getInt(1));

s.setName(rs.getString(2));

s.setAge(rs.getInt(3));

s.setAddress(rs.getString(4));

list.add(s);

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return list;

}

4.service层是业务层，是是和其他接口的层

首先创建StudentService.java

package com.hbsi.service;

import java.util.List;

import com.hbsi.domain.StudentBean;

public interface StudentService {

public List<StudentBean> findAll();

public List<StudentBean> listPage(intcurrentPage,int pageSzie);

//得到所有的记录行

public int getSize();

}

再创建StudentserviceImpl.java

package com.hbsi.service;

import java.util.List;

import com.hbsi.dao.StudentDaoImpl;

import com.hbsi.domain.StudentBean;

public class StudentServceImpl implements StudentService{

StudentDaoImpl dao = new StudentDaoImpl();

public List<StudentBean> findAll() {

// TODO Auto-generated method stub

return dao.findAll();

}

public List<StudentBean> listPage(int currentPage,int pageSize) {

// TODO Auto-generated method stub

return dao.listPage(currentPage, pageSize);

}

public int getSize() {

// TODO Auto-generated method stub

return dao.getSize();

}

5.jsp页面的实现 list.jsp

<%@ page language="java" import="java.util.*,com.hbsi.domain.*"

pageEncoding="utf-8"%>

String path = request.getContextPath();

String basePath = request.getScheme() + "://"

+ request.getServerName() + ":" +request.getServerPort()

+ path + "/";

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01Transitional//EN">

<html>

<head>

<title>My JSP 'list.jsp' starting page</title>

<!--

-->

</head>

<body>

List<StudentBean> list = (List<StudentBean>)request.getAttribute("list");

int pageNo = Integer.parseInt(request.getParameter("pageNo"));

<h3>

学生信息表

</h3>

<table>

for (int i = 0; i < list.size(); i++) {

<tr>

</tr>

}

</table><br/>

</body>

</html>

6.servlet层的实现 ControllerServlet.java

package com.hbsi.web;

import java.io.IOException;

import java.util.List;

importjavax.servlet.RequestDispatcher;

importjavax.servlet.ServletException;

importjavax.servlet.http.HttpServlet;

importjavax.servlet.http.HttpServletRequest;

importjavax.servlet.http.HttpServletResponse;

import com.hbsi.domain.StudentBean;

importcom.hbsi.service.StudentServceImpl;

public class ControllerServletextends HttpServlet {

/**

private static final long serialVersionUID = 1L;

public ControllerServlet() {

super();

}

public void destroy() {

super.destroy(); // Just puts "destroy" stringin log

// Put your code here

}

public void doGet(HttpServletRequest request,HttpServletResponse response)

throws ServletException, IOException {

doPost(request, response);

}

public void doPost(HttpServletRequest request,HttpServletResponse response)

throws ServletException, IOException {

// 通过服务层得到数据

StudentServceImpl service = new StudentServceImpl();

// List<StudentBean> list = service.findAll();

// 分页的操作

// 计算一下一共有多少页

int total = service.getSize();// 一共有多少行记录

int pageSize = 3;// 每页显示的记录行数

int totalPages = total / pageSize;//共有多少个页面显示

totalPages = (total % pageSize == 0) ? totalPages :totalPages + 1;// 总共有total页

//显示的页数

int currentPage = 1;

if (request.getParameter("pageNo") != null) {

currentPage = Integer.parseInt(request.getParameter("pageNo"));

}

if (currentPage < 1) {

currentPage = 1;

}

if(currentPage>totalPages){

currentPage=totalPages;

}

List<StudentBean> list=service.listPage(currentPage, pageSize);

// servlt和jsp的桥梁,设置作用域的范围

request.setAttribute("list", list);

// 通过jsp页面显示所有的数据,请求的转向

RequestDispatcher rd =request.getRequestDispatcher("list.jsp?pageNo="+currentPage);

rd.forward(request, response);

}

public void init() throws ServletException {

// Put your code here

}

这样简单的分页就做好了，大家好好看看吧！！本人是jsp的初学者，希望多多指点！