纯jQuery实现前端分页功能

2019-11-19 17:03:39

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来源：转载

供稿：网友

由于之前自己做过jquery分页，就是调用jni接口时，只能用前台分页解决显示问题。最近看到有人提这样的问题：一个请求传过来上万个数据怎么办？于是萌生了写这篇博客的想法。

效果展示：

因为核心代码主要在前端jquery，为了简便，后台就用servlet遍历本地磁盘目录文件的形式模拟响应的数据。

本项目的目录结构：

本项目的本地遍历文件夹结构：

处理显示请求的servlet:

package com.cn.action;import com.alibaba.fastjson.JSON;import com.cn.entity.Downloadfile;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.*;import java.util.ArrayList;import java.util.List;import java.util.Properties;/** * Created by Nolimitors on 2017/3/17. */public class PagesServlet extends HttpServlet{ protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {  /**   *@Author: Nolimitor   *@Params: * @param req   * @param resp   *@Date: 17:55 2017/3/17   */  doPost(req,resp); } protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {  /**  *@Author: Nolimitor  *@Params: * @param req   * @param resp  *@Date: 17:55 2017/3/17  */  Properties props = new Properties();  InputStream in = new BufferedInputStream(new FileInputStream(this.getClass().getResource("/fileroot.properties").getPath()));  props.load(in);  String rootPath = props.getProperty("Root");  List fileList = new ArrayList();   File file = new File(rootPath);   File []files = file.listFiles();   Downloadfile df = new Downloadfile();   for(File f:files) {    df.setName(f.getName());    df.setFilesize(Long.toString(f.length()));    System.out.println(f.getName());    fileList.add(JSON.toJSONString(df));   }  resp.addHeader("Content-type","application/json");  resp.setHeader("content-type", "text/html;charset=UTF-8");  resp.getWriter().print(JSON.toJSONString(fileList)); }}PagesServlet

处理下载文件请求的servlet：

package com.cn.action;import javax.servlet.ServletException;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.*;import java.net.URLEncoder;import java.util.Properties;/** * Created by Nolimitors on 2017/3/20. */public class DownloadFile extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {  doGet(req,resp); } @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {  //获取所要下载文件的路径  Properties props = new Properties();  InputStream in = new BufferedInputStream(new FileInputStream(this.getClass().getResource("/fileroot.properties").getPath()));  props.load(in);  String rootPath = props.getProperty("Root");  String name = req.getParameter("filename");  name = new String(name.getBytes("ISO8859-1"),"UTF-8");  System.out.println(name);  //处理请求  //读取要下载的文件  File f = new File(rootPath+"//"+ name);  if(f.exists()){   FileInputStream fis = new FileInputStream(f);   String filename=java.net.URLEncoder.encode(f.getName(),"utf-8"); //解决中文文件名下载乱码的问题   byte[] b = new byte[fis.available()];   fis.read(b);   //解决中文文件名下载后乱码的问题   resp.setContentType("application/x-msdownload");   resp.setHeader("Content-Disposition", "attachment;filename="+     new String(filename.getBytes("utf-8"),"ISO-8859-1"));   //获取响应报文输出流对象   ServletOutputStream out =resp.getOutputStream();   //输出   out.write(b);   out.flush();   out.close();  } }}DownloadFile

web.xml配置：

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"   version="3.1"> <servlet>  <servlet-name>PageServlet</servlet-name>  <servlet-class>com.cn.action.PagesServlet</servlet-class> </servlet> <servlet-mapping>  <servlet-name>PageServlet</servlet-name>  <url-pattern>/doPages</url-pattern> </servlet-mapping> <servlet>  <servlet-name>DownServlet</servlet-name>  <servlet-class>com.cn.action.DownloadFile</servlet-class> </servlet> <servlet-mapping>  <servlet-name>DownServlet</servlet-name>  <url-pattern>/download</url-pattern> </servlet-mapping></web-app>web.xml

前台完整html代码：

<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <link href="/resource/juqery/css/base/jquery-ui-1.9.2.custom.css" rel="external nofollow" rel="stylesheet"> <link href="/resource/css/css.css" rel="external nofollow" rel="stylesheet"> <script type="application/javascript" src="/resource/common.js"></script> <script type="application/javascript" src="/resource/juqery/js/jquery-1.8.3.js"></script> <script type="application/javascript" src="/resource/juqery/js/jquery-ui-1.9.2.custom.js"></script> </head> <script type="application/javascript"> //请求一次数据，然后存储到js变量中，保证只发送一条请求 var datas; jQuery(function() {  $.ajax({   type: "POST",   url: "/doPages",   data: "{}",   dataType: 'json',   success: function(data) {   datas = data;   getPages(1,5);   }  }); }); //用于页码跳转方法 function jumPage(totalPage,psize){  var cpage=jQuery("#page_no").val();  if(0< cpage && cpage <= totalPage){  getPages(cpage,psize);  }  else{  alert("Out of range");  } } function getPages(pno,psize) {  var num;//分页总行数  var totalPage = 0;//分页总页数  var pageSize = psize;//分页每行显示数  var currentPage = pno;//当前页  num = parseInt(datas.length);//获取数据行数  if (num / pageSize > parseInt(num / pageSize)) {  totalPage = parseInt(num / pageSize) + 1;  } else {  totalPage = parseInt(num / pageSize);  }  var startRow = (currentPage - 1) * pageSize + 1;//开始显示的行  var endRow = currentPage * pageSize;//结束显示的行  endRow = (endRow > num) ? num : endRow;  var tbody = jQuery("#list_data>tbody");  tbody.empty();  jQuery.each(datas, function (i, n) {  var file = JSON.parse(n);  if (startRow <= parseInt(i + 1) && parseInt(i + 1) <= endRow) {   var row = createRow().appendTo(tbody);   //多选用，目前暂时未考虑   /* createColumn().html("<input type='checkbox' id="+"fileId"+(i+1)+" name='fileId'/>").appendTo(row);*/   createColumn().text(i + 1).appendTo(row);   createColumn().text(file.name).appendTo(row);   createColumn().text(getSize(file.filesize)).appendTo(row);   var operationColumn = createColumn().appendTo(row);  }  //每次执行分页代码时需要将前一次分页的判断结果清空  jQuery("#last_page").removeAttr("onclick");  jQuery("#next_page").removeAttr("onclick");  //当前页非第一页时  if (currentPage > 1) {   jQuery("#last_page").attr("onclick", "getPages(" + (parseInt(currentPage) - 1) + "," + psize + ")");  }  //当前页小于总页数时  if (currentPage < totalPage) {   jQuery("#next_page").attr("onclick", "getPages(" + (parseInt(currentPage) + 1) + "," + psize + ")");  }  //显示当前页码、总页数及生成跳转点击事件  jQuery("#end_page").attr("onclick", "getPages(" + (totalPage) + "," + psize + ")");  jQuery("#first_page").attr("onclick", "getPages(" + (1) + "," + psize + ")");  jQuery("#jump_page").attr("onclick", "jumPage(" + (totalPage) + "," + psize + ")");  jQuery("#total_page").val("/" + totalPage + " 页");  jQuery("#page_no").val(currentPage);  var btnDownload = jQuery("<button class='btn_download'>下载</button>");  var btnDelete = jQuery("<button class='btn_delete'>删除</button>");  //批量删除获取文件信息用，目前暂时不用  /*jQuery("#"+"fileId"+(i+1)).attr("recordQuery",JSON.stringify(recordQuery));*/  btnDownload.click(function () {   location.href = "/download?filename=" + file.name;  });  btnDelete.click(function () {   recordQuery = jQuery(this).attr("data-record-query");   var dialogDiv = jQuery("<div></div>");   dialogDiv.dialog({   autoOpen: false,   modal: true,   width: 500,   position: {my: "center", at: "center", of: jQuery(".content_wrapper_hidden")},   title: "文件删除",   buttons: [    {    text: "确认",    click: function () {   jQuery.post("/delete", file.name, function (data) {    location.reload();   });   jQuery(this).dialog("close");   }  },   {   text: "取消",     click: function () {   jQuery(this).dialog("close");   }   }   ]  });   var text = "确认删除 "+ file.name + "?";   dialogDiv.text(text).dialog("open");  });  btnDownload.appendTo(operationColumn);  btnDelete.appendTo(operationColumn);  });  jQuery(".btn_download,.btn_delete").button(); } function getSize(length) {  var len, unit;  if (length == 0) {  len = 0;  unit = "B";  } else if (length < 1024) {  len = length;  unit = "B";  } else if (length < (1024 * 1024)) {  len = (length / 1024);  unit = "KB";  } else {  len = (length / 1024 / 1024);  unit = "MB";  }  return new Number(len).toFixed(2) + unit; } </script> <style> .data tbody tr td:first-child{  font-weight:bold;  cursor: pointer; } </style> <body> <div class="main_wrapper">  <div class="content_wrapper_hidden">  <div class="ui_wrapper">  <table id="list_data" class="data" border="0" cellspacing="0" cellpadding="0" style="width: 100%">  <thead>  <tr>   <th >Num</th>   <th >Files</th>   <th >Size</th>   <th >Operation</th>  </tr>  </thead>  <tbody>  </tbody>  </table>   <!-- 分页用按钮-->   <table class="ui-corner-all grey" style="width: 100%">   <tbody align="center" valign="middle">   <tr><td><div id="pagination"><!-- 全选和批量删除按钮，目前暂时未考虑--><!--<input type="button" id='fileIds' style="background: -moz-linear-gradient(top,#ffffff,#e6e6e6);border-color:#c5c5c5" value="全选"/><input type="button" id='delete_fileIds' style="background: -moz-linear-gradient(top,#ffffff,#e6e6e6);border-color:#c5c5c5" value="删除"/>-->    <input type="button" id='first_page' style="background: -moz-linear-gradient(top,#ffffff,#e6e6e6);border-color:#c5c5c5" value="首页"/><input type="button" style="background: -moz-linear-gradient(top,#ffffff,#e6e6e6);border-color:#c5c5c5" id='last_page' value="上一页"/><input type="button" id='next_page' style="background: -moz-linear-gradient(top,#ffffff,#e6e6e6);border-color:#c5c5c5" value="下一页"/><input type="button" style="background: -moz-linear-gradient(top,#ffffff,#e6e6e6);border-color:#c5c5c5" id='end_page' value="尾页"/><input type="button" style="background: -moz-linear-gradient(top,#ffffff,#e6e6e6);border-color:#c5c5c5" id='jump_page' value="跳转"/>    <input autocomplete="off" class="ui-autocomplete-input" id="page_no" style="height: 20px;width:30px"/><input type="button" style="background: -moz-linear-gradient(top,#ffffff,#e6e6e6);border: none" id='total_page' value="0 页" /></div></td></tr>   </tbody>   </table>  <!-- 分页用按钮-->   </div>  </div>  </div> </body></html>

分页的核心jquery代码：

function getPages(pno,psize) {  var num;//分页总行数  var totalPage = 0;//分页总页数  var pageSize = psize;//分页每行显示数  var currentPage = pno;//当前页  num = parseInt(datas.length);//获取数据行数  if (num / pageSize > parseInt(num / pageSize)) {  totalPage = parseInt(num / pageSize) + 1;  } else {  totalPage = parseInt(num / pageSize);  }  var startRow = (currentPage - 1) * pageSize + 1;//开始显示的行  var endRow = currentPage * pageSize;//结束显示的行  endRow = (endRow > num) ? num : endRow;  var tbody = jQuery("#list_data>tbody");  tbody.empty();  jQuery.each(datas, function (i, n) {  var file = JSON.parse(n);  if (startRow <= parseInt(i + 1) && parseInt(i + 1) <= endRow) {   var row = createRow().appendTo(tbody);   //多选用，目前暂时未考虑   /* createColumn().html("<input type='checkbox' id="+"fileId"+(i+1)+" name='fileId'/>").appendTo(row);*/   createColumn().text(i + 1).appendTo(row);   createColumn().text(file.name).appendTo(row);   createColumn().text(getSize(file.filesize)).appendTo(row);   var operationColumn = createColumn().appendTo(row);  }  //每次执行分页代码时需要将前一次分页的判断结果清空  jQuery("#last_page").removeAttr("onclick");  jQuery("#next_page").removeAttr("onclick");  //当前页非第一页时  if (currentPage > 1) {   jQuery("#last_page").attr("onclick", "getPages(" + (parseInt(currentPage) - 1) + "," + psize + ")");  }  //当前页小于总页数时  if (currentPage < totalPage) {   jQuery("#next_page").attr("onclick", "getPages(" + (parseInt(currentPage) + 1) + "," + psize + ")");  }  //显示当前页码、总页数及生成跳转点击事件  jQuery("#end_page").attr("onclick", "getPages(" + (totalPage) + "," + psize + ")");  jQuery("#first_page").attr("onclick", "getPages(" + (1) + "," + psize + ")");  jQuery("#jump_page").attr("onclick", "jumPage(" + (totalPage) + "," + psize + ")");  jQuery("#total_page").val("/" + totalPage + " 页");  jQuery("#page_no").val(currentPage);  var btnDownload = jQuery("<button class='btn_download'>下载</button>");  var btnDelete = jQuery("<button class='btn_delete'>删除</button>");  //批量删除获取文件信息用，目前暂时不用  /*jQuery("#"+"fileId"+(i+1)).attr("recordQuery",JSON.stringify(recordQuery));*/  btnDownload.click(function () {   location.href = "/download?filename=" + file.name;  });  btnDelete.click(function () {   recordQuery = jQuery(this).attr("data-record-query");   var dialogDiv = jQuery("<div></div>");   dialogDiv.dialog({   autoOpen: false,   modal: true,   width: 500,   position: {my: "center", at: "center", of: jQuery(".content_wrapper_hidden")},   title: "文件删除",   buttons: [    {    text: "确认",    click: function () {   jQuery.post("/delete", file.name, function (data) {    location.reload();   });   jQuery(this).dialog("close");   }  },   {   text: "取消",     click: function () {   jQuery(this).dialog("close");   }   }   ]  });   var text = "确认删除 "+ file.name + "?";   dialogDiv.text(text).dialog("open");  });  btnDownload.appendTo(operationColumn);  btnDelete.appendTo(operationColumn);  });  jQuery(".btn_download,.btn_delete").button(); }

用于页面跳转的js代码：

//用于页码跳转方法 function jumPage(totalPage,psize){  var cpage=jQuery("#page_no").val();  if(0< cpage && cpage <= totalPage){  getPages(cpage,psize);  }  else{  alert("Out of range");  } }

计算文件的大小js：

function getSize(length) {  var len, unit;  if (length == 0) {  len = 0;  unit = "B";  } else if (length < 1024) {  len = length;  unit = "B";  } else if (length < (1024 * 1024)) {  len = (length / 1024);  unit = "KB";  } else {  len = (length / 1024 / 1024);  unit = "MB";  }  return new Number(len).toFixed(2) + unit; }

页面默认请求jquery：

//请求一次数据，然后存储到js变量中，保证只发送一条请求 var datas; jQuery(function() {  $.ajax({   type: "POST",   url: "/doPages",   data: "{}",   dataType: 'json',   success: function(data) {   datas = data;   getPages(1,5);   }  }); });

项目中用到了便于生成table的自己编写的js工具：

function createColumn() { return jQuery("<td></td>");}function createRow() { return jQuery("<tr></tr>");}function createEle(tag){ return jQuery("<"+tag+"></"+tag+">");}function reload(){ window.location.reload();} function toURL(url){ window.location.href=url;}function isString(obj){ return typeof(obj) == "string";}function isObject(obj){ return typeof(obj) == "object";}function fillSelect(select, data, valueKey, textKey){ var $select = isString(select) ? jQuery(select) : select; $select.empty(); jQuery.each(data, function(i, item){  var value = (!isString(item)) ? item[valueKey] : item;  var text = (!isString(item)) ? item[textKey] : item;  var $op = createEle("option").appendTo($select);  $op.text(text).val(value); })}common.js

为了美观考虑，项目中引用了jquery UI：