jsp分页

最新推荐文章于 2025-11-30 19:25:58 发布

原创最新推荐文章于 2025-11-30 19:25:58 发布 · 352 阅读

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CC 4.0 BY-SA版权

文章标签：

#jsp #string #数据库 #list #dao #servlet

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 {

private int id;

private String name;

private int age;

private String address;

public StudentBean() {

super();

// TODOAuto-generated constructor stub

}

public StudentBean(int id, Stringname, intage, 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

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(int currentPage,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 (SQLExceptione) {

// 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 = new LinkedList<StudentBean>();

try {

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

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 (SQLExceptione) {

// 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-generatedmethod 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 = new LinkedList<StudentBean>();

try {

//记录行

int recordIndex=(currentPage-1)*pageSize;

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

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 (SQLExceptione) {

// 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(int currentPage,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 = newStudentDaoImpl();

public List<StudentBean> findAll(){

// TODO Auto-generatedmethod stub

return dao.findAll();

}

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

// TODO Auto-generatedmethod stub

returndao.listPage(currentPage, pageSize);

}

public int getSize() {

// TODO Auto-generatedmethod 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 4.01 Transitional//EN">

<html>

<head>

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

<!--

-->

</head>

<body>

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

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

<h3>

学生信息表

</h3>

<table>

for(inti = 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;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.hbsi.domain.StudentBean;

import com.hbsi.service.StudentServceImpl;

public class ControllerServlet extends HttpServlet {

/**

private static final longserialVersionUID = 1L;

public ControllerServlet() {

super();

}

public void destroy() {

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

// Put your code here

}

public void doGet(HttpServletRequestrequest, HttpServletResponse response)

throws ServletException, IOException {

doPost(request,response);

}

public void doPost(HttpServletRequestrequest, HttpServletResponse response)

throws ServletException, 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

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

}