纯jQuery实现前端分页功能

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：

 
  PageServlet
  com.cn.action.PagesServlet
 
 
  PageServlet
  /doPages
 
 
  DownServlet
  com.cn.action.DownloadFile
 
 
  DownServlet
  /download
 


web.xml

前台完整html代码：

 
 
 
 
 
 
 
 
 
 
 
 

  

  

  

  

  

   
Num
   
Files
   
Size
   
Operation
  
  
  

  
  
   
   
  
   
  
  
 

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("").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("下载");
  var btnDelete = jQuery("删除");
  //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("
");
   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("");
}
function createRow() {
 return jQuery("");
}
function createEle(tag){
 return jQuery("<"+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：

代码.GitHub：https://github.com/Wenchaozou/JqueryForPages

百度云链接：https://pan.baidu.com/s/1dE5Cj5n

以上就是本文的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，同时也希望多多支持脚本之家！