广场 › 开发技术 › jsp servlet javaBean后台分页实例代码解析

Shun 发表于 2021-10-20 22:20:47

jsp servlet javaBean后台分页实例代码解析

首先后台分页需要理清分页思路，把数据库里面需要分页的信息放到List集合中，然后按照页面反馈给后台的页码对List集合进行SubList切割把切完的List传到前端进行显示。

1.分页的demo文件结构图

导入的包

2.代码

SplitPageServlet代码


package ActionServlet;

import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import Bean.ProjectBean;
import Service.SplitPage;

/**
* Servlet implementation class SplitPageServlet
*/
@WebServlet("/SplitPageServlet")
public class SplitPageServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#HttpServlet()
*/
public SplitPageServlet() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
List<ProjectBean>listArr = new ArrayList<ProjectBean>();
String currrentPageString = request.getParameter("currrentPage");
String numberForSplitPage = request.getParameter("numberForSplitPage");
if( currrentPageString ==null){
   currrentPageString = "1";
}
if( numberForSplitPage == null){
   numberForSplitPage = "5";
}
SplitPage splitPage = new SplitPage();
try {
   listArr = splitPage.AllSplitPage(numberForSplitPage, currrentPageString);
   request.setAttribute("subResult", listArr);
} catch (ClassNotFoundException | SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
}
System.out.println(SplitPage.pageNumber);
System.out.println(SplitPage.currentPageIndex);
request.setAttribute("pageNumber", SplitPage.pageNumber);
request.setAttribute("currentPageIndex", SplitPage.currentPageIndex);
request.getRequestDispatcher("/servlet/ShowViewIndex").forward(request, response);

}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}

}

ProjectBean代码


package Bean;

public class ProjectBean {
private String projectId = null;
private String projectName = null;
private String projectType = null;
private String userNo = null;
private String projectUser = null;
public String getProjectId(){
if(projectId==null){
   projectId ="";
}
return this.projectId;
}
public void setProjectId(String projectId){
this.projectId = projectId;
}

public void setProjectName(String projectName){
this.projectName = projectName;
}

public String getProjectName(){
return this.projectName;
}

public void setType(String projectType){
this.projectType = projectType;
}

public String getProjectType(){
return this.projectType;
}

public void setUserNo(String userNo){
this.userNo = userNo;
}

public String getUserNo(){
return this.userNo;
}

public void setProjectUser(String projectUser){
this.projectUser = projectUser;
}

public String getProjectUser(){
return this.projectUser;
}

}

SplitPageBean 代码


package Bean;

public class SplitPageBean {
private int allitems;//总的记录数
private int currentRecord;//当前的记录数
private int lastPageRecord ; //上一页记录数开始数
private int nextPageRecord;//下一页记录数开始数
private int lastPageIndex ; //上一页
private int nextPageIndex;//下一页
private int currentPageIndex;//当前页
private int numberForSplitPage;//每页分的数量
private int allPageNumber;

public int getAllitems(){
return this.allitems;
}
public void setAllitems(int allitems){
this.allitems = allitems;
}

public int getCurrentRecord(){
return this.currentRecord;
}
public void setCurrentRecord(int currentPageIndex){
this.currentRecord = currentPageIndex * this.numberForSplitPage;
}

public int getlastPageRecord(){
return this.lastPageRecord;
}
public void setLastPageRecord(int lastPageIndex){
this.lastPageRecord = lastPageIndex * this.numberForSplitPage;
}

public int getNextPageRecord(){
return this.nextPageRecord;
}
public void setNextPageRecord(int nextPageIndex){
this.nextPageRecord = nextPageIndex * this.numberForSplitPage;
}

public int getLastPageIndex(){
return this.lastPageIndex;
}
public void setLastPageIndex(int currentPageIndex){
this.lastPageIndex = currentPageIndex - 1;
}

public int getNextPageIndex(){
return this.nextPageIndex;
}
public void setNextPageIndex(int currentPageIndex){
this.nextPageIndex = currentPageIndex - 1;
}

public int getCurrentPageIndex(){
return this.currentPageIndex;
}
public void setCurrentPageIndex(int currentPageIndex){
this.currentPageIndex = currentPageIndex;
}

public int getNumberForSplitPage(){
return this.numberForSplitPage;
}
public void setNumberForSplitPage(int numberForSplitPage){
this.numberForSplitPage = numberForSplitPage;
}

public int getAllPageNumber(){
return this.allPageNumber;
}
public void setAllPageNumber(int allitems){
this.allPageNumber = allitems / this.numberForSplitPage + 1;
}

}

QueryProject代码


package Dao;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import Bean.ProjectBean;
import Service.ConnectDataBase;

public class QueryProject {
private List<ProjectBean> listArr = new ArrayList();
public List<ProjectBean> QueryAllProject() throws ClassNotFoundException, SQLException{
Connection conn=null;
Statement stat=null;
ResultSet rs=null;
ConnectDataBase connectDataBase =new ConnectDataBase();
conn = connectDataBase.connect();
stat = conn.createStatement();
rs = stat.executeQuery("select*from project");

while(rs.next()){
   ProjectBean projectBean = new ProjectBean();
   projectBean.setProjectId(rs.getString("projectId"));
   projectBean.setProjectName(rs.getString("projectName"));
   projectBean.setType(rs.getString("projectType"));
   projectBean.setUserNo(rs.getString("UserNo"));
   projectBean.setProjectUser(rs.getString("projectUser"));
   listArr.add(projectBean);
}
connectDataBase.close(stat, conn);
return listArr;
}
// public static void main(String[] args) throws ClassNotFoundException, SQLException{
//List<ProjectBean> listArr = new ArrayList();
//QueryProject queryProject = new QueryProject();
//listArr = queryProject.QueryAllProject();
//ProjectBean projectBean = new ProjectBean();
//projectBean = listArr.get(0);
//System.out.println(projectBean.getProjectId());
//projectBean = listArr.get(2);
//System.out.println(projectBean.getProjectId());
//System.out.println(listArr.size());
// }
}

ConenctDataBase代码


package Service;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

public class ConnectDataBase {
private String url = "jdbc:MySQL://localhost:3306/zhongchuangweb";
private String user = "root";
private String password = "12345";

public Connection connect() throws ClassNotFoundException, SQLException{
   Class.forName("com.mysql.jdbc.Driver");
   Connection conn = DriverManager.getConnection(url,user,password);
   return conn;
}
//关闭数据库资源
public void close(Statement stat,Connection conn) throws SQLException{
if(stat!=null){
    stat.close();
}
if(conn!=null){
    conn.close();
}
}
}

SplitPage代码


package Service;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import Bean.ProjectBean;
import Bean.SplitPageBean;
import Dao.QueryProject;

public class SplitPage {
public static int pageNumber;
public static int currentPageIndex;
private List<ProjectBean> splitArr = new ArrayList();

{
QueryProject queryProject = new QueryProject();
try {
   splitArr = queryProject.QueryAllProject();
} catch (ClassNotFoundException | SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
}
}
public List<ProjectBean> AllSplitPage(String numberForSplitPage,String requestPageIndex) throws ClassNotFoundException, SQLException{
List<ProjectBean> result = new ArrayList<ProjectBean>();
int numberForSplitPageInt = Integer.parseInt(numberForSplitPage);//每页的数量
int requestPageIndexInt = Integer.parseInt(requestPageIndex);//请求的页码
SplitPageBean splitPageBean = new SplitPageBean();
splitPageBean.setAllitems(splitArr.size());//设置总的记录数
splitPageBean.setNumberForSplitPage(numberForSplitPageInt);//设置每页的记录数量
splitPageBean.setAllPageNumber(splitArr.size());
pageNumber = splitPageBean.getAllPageNumber();
splitPageBean.setCurrentPageIndex(requestPageIndexInt);//设置请求页页码
currentPageIndex = splitPageBean.getCurrentPageIndex();
splitPageBean.setLastPageRecord(requestPageIndexInt-1);
if(splitPageBean.getAllitems()<splitPageBean.getNumberForSplitPage()){
   result = splitArr;
}else if(splitPageBean.getCurrentPageIndex()*splitPageBean.getNumberForSplitPage() > splitPageBean.getAllitems()){
   result = splitArr.subList(splitPageBean.getlastPageRecord(),splitPageBean.getAllitems());
}else{
   result = splitArr.subList(splitPageBean.getlastPageRecord(),splitPageBean.getlastPageRecord()+splitPageBean.getNumberForSplitPage());//SubList用法不包含末尾索引
}
return result;
}

// public static void main(String[] args) throws ClassNotFoundException, SQLException{
//List<ProjectBean> TestResult = new ArrayList<ProjectBean>();
//ProjectBean projectBean = new ProjectBean();
//SplitPage splitPage = new SplitPage();
//TestResult = splitPage.AllSplitPage("5","1");
//projectBean = TestResult.get(0);
//System.out.println(projectBean.getProjectId());
//projectBean = TestResult.get(1);
//System.out.println(projectBean.getProjectId());
//projectBean = TestResult.get(2);
//System.out.println(projectBean.getProjectId());
//projectBean = TestResult.get(3);
//System.out.println(projectBean.getProjectId());
//projectBean = TestResult.get(4);
//System.out.println(projectBean.getProjectId());
//projectBean = TestResult.get(5);
//System.out.println(projectBean.getProjectId());
//   
// }

}

显示层
ShowViewIndex代码


package View;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* Servlet implementation class ShowViewIndex
*/
@WebServlet("/ShowViewIndex")
public class ShowViewIndex extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#HttpServlet()
*/
public ShowViewIndex() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.getRequestDispatcher("/NewFile.jsp").forward(request, response);
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}

}

jsp页面代码


<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<%@ taglib prefix="c" uri="https://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>数据库内容分页显示</title>
<style type="text/css">
*{ margin:0; padding:0;}
ul li{ width:50px; height:24px; line-height:24px; float:left; margin-left:0px; display:inline; margin-top:5px; overflow:hidden;}
ul li button{width:50px;height:24px;margin:0px;padding:0px;}
</style>
</head>
<body>
<table>
<thead>
   <tr>
    <th style="text-align:center;">编号</th>
    <th style="text-align:center;">名称</th>
    <th style="text-align:center;">类型</th>
    <th style="text-align:center;">学号</th>
    <th style="text-align:center;">负责人</th>
   </tr>
</thead>
<tbody>
    <c:forEach var="project" items="${subResult}">
   <tr>
      <td><c:out value="${project.projectId}"></c:out></td>
      <td><c:out value="${project.projectName}"></c:out></td>
      <td><c:out value="${project.projectType}"></c:out></td>
      <td><c:out value="${project.userNo}"></c:out></td>
      <td><c:out value="${project.projectUser}"></c:out></td>
   </tr>
    </c:forEach>
</tbody>
</table>
<div align = "center">
    <ul>
    <c:choose>
   <c:when test="${currentPageIndex>1}">
       <li><a href="${pageContext.request.contextPath}/servlet/SplitPageServlet?currrentPage=${currentPageIndex-1}"><button><</button></a></li>
   </c:when>
   <c:otherwise>
       <li><a><button><</button></a></li>
   </c:otherwise>
    </c:choose>
   <%
      int i =(Integer)request.getAttribute("pageNumber");
       for (int j=0;j<i;j++)
       {%>
       <li><a href="${pageContext.request.contextPath}/servlet/SplitPageServlet?currrentPage=<%=j+1%>"><button><%=j+1%></button></a></li>
      <%}%>
   <c:choose>
   <c:when test="${currentPageIndex+1<=pageNumber}">
       <li><a href="${pageContext.request.contextPath}/servlet/SplitPageServlet?currrentPage=${currentPageIndex+1}"><button>></button></a></li>
   </c:when>
   <c:otherwise>
       <li><a><button>></button></a></li>
   </c:otherwise>
    </c:choose>
    </ul>
   </div>
</body>
</html>
xml代码


<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance" xmlns="https://java.sun.com/xml/ns/javaee" xsi:schemaLocation="https://java.sun.com/xml/ns/javaee https://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
<display-name></display-name>
<welcome-file-list>
<welcome-file>SplitPageServlet</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>ShowViewIndex</servlet-name>
<servlet-class>View.ShowViewIndex</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ShowViewIndex</servlet-name>
<url-pattern>/servlet/ShowViewIndex</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>SplitPageServlet</servlet-name>
<servlet-class>ActionServlet.SplitPageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>SplitPageServlet</servlet-name>
<url-pattern>/servlet/SplitPageServlet</url-pattern>
</servlet-mapping>
</web-app>
运行结果展示


数据库describe


同时在本次demo中认识到了xml的中使用欢迎界面通过<welcome-file-list><welcome-file>静态界面（jsp html）</welcome-file> </welcome-file-list>还可以使用servlet直接用servlet名即可。
初学java和javaee 写一点自己做的东西，代码写的不是很规范，不喜勿喷。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持CodeAE代码之家。

https://www.uoften.com/program/jsp/20180413/48036.html

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