Jsp的分页操作源代码

最新推荐文章于 2021-02-21 14:33:22 发布

原创最新推荐文章于 2021-02-21 14:33:22 发布 · 1.1k 阅读

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CC 4.0 BY-SA版权

文章标签：

#jsp #string #数据库 #servlet #interface #list

一分页操作的分析：

1．web开发模式的三层架构

2．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

3．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

4．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

public class StudentBean {

private int id;

private String name;

private int age;

private String address;

public StudentBean() {

super();

// TODO Auto-generatedconstructor stub

}

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

super();

this.id = id;

this.name = name;

this.age = age;

this.address = address;

}

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

public String getAddress() {

return address;

}

public void 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

publicList<StudentBean> findAll();

//返回指定页中显示的记录行（一共有多少页，共多长）

publicList<StudentBean> listPage(int currentPage,int pageSize);

//返回所有记录的行数

public intgetSize();

}

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 implementsStudentDao {

//声明操作的数据库对象

privatestatic Connection conn;

privatePreparedStatement pstmt;

privateResultSet rs;

//第一步：准备驱动程序，构造到项目路径中

privatestatic 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 intsize;//记录多少行

publicList<StudentBean> findAll() {

//存放读取的数据

List<StudentBean>list = new LinkedList<StudentBean>();

try {

pstmt= conn.prepareStatement("select * from student");

rs = pstmt.executeQuery();

//从结果集中读取

while(rs.next()){

StudentBeans = 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 (SQLExceptione) {

//TODO Auto-generated catch block

e.printStackTrace();

}

size=list.size();

returnlist;

}

//获取总的记录行数

public intgetSize() {

// TODOAuto-generated method stub

findAll();

returnsize;

}

//截取的读取

publicList<StudentBean> listPage(int currentPage, int pageSize) {

//存放读取的数据

List<StudentBean>list = new LinkedList<StudentBean>();

try {

//记录行

intrecordIndex=(currentPage-1)*pageSize;

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

intindex =1;

pstmt.setInt(index++,recordIndex);

pstmt.setInt(index++,pageSize);

//从结果集中读

rs =pstmt.executeQuery();

while(rs.next()){

StudentBeans = 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();

}

returnlist;

}

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 {

publicList<StudentBean> findAll();

publicList<StudentBean> listPage(int currentPage,int pageSzie);

//得到所有的记录行

public intgetSize();

}

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 implementsStudentService {

StudentDaoImpldao = new StudentDaoImpl();

publicList<StudentBean> findAll() {

// TODOAuto-generated method stub

returndao.findAll();

}

publicList<StudentBean> listPage(int currentPage, int pageSize) {

// TODOAuto-generated method stub

returndao.listPage(currentPage, pageSize);

}

public intgetSize() {

// TODOAuto-generated method stub

returndao.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;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

importjavax.servlet.http.HttpServletRequest;

importjavax.servlet.http.HttpServletResponse;

import com.hbsi.domain.StudentBean;

import com.hbsi.service.StudentServceImpl;

public class ControllerServlet extendsHttpServlet {

/**

privatestatic final long serialVersionUID = 1L;

publicControllerServlet() {

super();

}

public voiddestroy() {

super.destroy();// Just puts "destroy" string in log

// Putyour code here

}

public voiddoGet(HttpServletRequest request, HttpServletResponse response)

throwsServletException, IOException {

doPost(request,response);

}

public voiddoPost(HttpServletRequest request, HttpServletResponse response)

throwsServletException, IOException {

// 通过服务层得到数据

StudentServceImplservice = new StudentServceImpl();

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

// 分页的操作

// 计算一下一共有多少页

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

intpageSize = 3;// 每页显示的记录行数

inttotalPages = 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

intcurrentPage = 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

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

rd.forward(request,response);

}

public voidinit() throws ServletException {

// Putyour 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！