jsp servlet javaBean後台分頁執行個體代碼解析_JSP編程

首先後台分頁需要理清分頁思路，把資料庫裡面需要分頁的資訊放到List集合中，然後按照頁面反饋給背景頁碼對List集合進行SubList切割把切完的List傳到前端進行顯示。

1.分頁的demo檔案結構圖

匯入的包

2.代碼

SplitPageServlet代碼

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代碼

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 代碼

package Bean;public class SplitPageBean { private int allitems;//總的記錄數 private int currentRecord;//當前的記錄數 private int lastPageRecord ; //上一頁記錄數開始數 private int nextPageRecord;//下一頁記錄數開始數 private int lastPageIndex ; //上一頁 private int nextPageIndex;//下一頁 private int currentPageIndex;//當前頁 private int numberForSplitPage;//每頁分的數量 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代碼

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代碼

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; } //關閉資料庫資源 public void close(Statement stat,Connection conn) throws SQLException{  if(stat!=null){    stat.close();  }  if(conn!=null){    conn.close();  } }}

SplitPage代碼

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);//每頁的數量  int requestPageIndexInt = Integer.parseInt(requestPageIndex);//請求的頁碼  SplitPageBean splitPageBean = new SplitPageBean();  splitPageBean.setAllitems(splitArr.size());//設定總的記錄數  splitPageBean.setNumberForSplitPage(numberForSplitPageInt);//設定每頁的記錄數量  splitPageBean.setAllPageNumber(splitArr.size());  pageNumber = splitPageBean.getAllPageNumber();  splitPageBean.setCurrentPageIndex(requestPageIndexInt);//佈建要求頁頁碼  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());//    // }}

顯示層
ShowViewIndex代碼

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頁面代碼

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>資料庫內容分頁顯示</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;">編號</th>    <th style="text-align:center;">名稱</th>    <th style="text-align:center;">類型</th>    <th style="text-align:center;">學號</th>    <th style="text-align:center;">負責人</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代碼

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://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>

運行結果展示

資料庫describe

同時在本次demo中認識到了xml的中使用歡迎介面通過  <welcome-file-list>  <welcome-file>靜態介面（jsp html）</welcome-file> </welcome-file-list>還可以使用servlet直接用servlet名即可。
初學java和javaee 寫一點自己做的東西，代碼寫的不是很規範，不喜勿噴。

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