dataTables是一种很好用前端表格显示库。当加载大量数据时,可以用Ajax 获取数据来提高效率,增速网页加载速率。下面以一个例子作示范。
首先,需要下载jQuery以及dataTables库。这里使用的是版本是jquery v1.11.3和DataTables 1.10.9。下载网址:http://datatables.NET/。
先上网页的代码。要注意的是,table中的thead和tbody必须要有。
- <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
- <html>
- <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
- <head>
- <link href="http://www.zhuhaihengxin.com/libs/datatables/1.10.0/css/jquery.dataTables.css" rel="stylesheet">
- <title>dataTable example</title>
- <script type="text/javascript" src="jquery.js"></script>
- <script type="text/javascript" src="jquery.dataTables.js"></script>
- <script type="text/javascript">
- $(document).ready(function() {
- $("#datatable").dataTable({
- "processing" : true,
- "serverSide" : true,
- "paginationType":"full_numbers",
- "ajax" : "load",
- "columns" : [
- {"data" : "id"},
- {"data" : "firstName"},
- {"data" : "lastName"}
- ]
- });
- });
- </script>
- <style>
- h2{
- text-align:center;
- }
- div {
- float: left;
- margin: 10px;
- padding: 4px;
- }
- a{
- margin:5px;
- }
- table,tr,td,th{
- border:2px solid #3aec7b;
- border-collapse:collapse;
- }
- </style>
- </head>
- <body>
- <TABLE id="datatable">
- <THEAD>
- <tr>
- <th>ID</th>
- <th>First Name</th>
- <th>Last Name</th>
- </tr>
- </THEAD>
- <tbody>
- </tbody>
- </TABLE>
- </body>
- </html>
当网页加载的时候,ajax发出请求,如下所示。
- draw=[1]
- columns[0][data]=[id]
- columns[0][name]=[]
- columns[0][searchable]=[true]
- columns[0][orderable]=[false]
- columns[0][search][value]=[]
- columns[0][search][regex]=[false]
- columns[1][data]=[firstName]
- columns[1][name]=[]
- columns[1][searchable]=[true]
- columns[1][orderable]=[true]
- columns[1][search][value]=[]
- columns[1][search][regex]=[false]
- columns[2][data]=[lastName]
- columns[2][name]=[]
- columns[2][searchable]=[true]
- columns[2][orderable]=[true]
- columns[2][search][value]=[]
- columns[2][search][regex]=[false]
- order[0][column]=[0]
- order[0][dir]=[asc]
- start=[0]
- length=[10]
- search[value]=[]
- search[regex]=[false]
- _=[1441278114568]
其中,draw是请求的序号,start是数据的偏移量,length是需要返回的最大数据条数。search[value]是查找的值。
服务端采用Java的servlet完成。为简单起见,这里直接采用继承HttpServlet的方式实现。数据本应该从数据库中提取,但这里为了简单,生成了静态数据集合作为数据源。每次请求都从集合中查找匹配的数据,然后转换成JSON返回。JSON库采用阿里的fastjson。
代码如下所示。
- package jspTest;
- import java.io.IOException;
- import java.util.ArrayList;
- import java.util.Arrays;
- import java.util.Enumeration;
- import java.util.LinkedList;
- import java.util.Random;
- 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 com.alibaba.fastjson.JSON;
- import com.alibaba.fastjson.JSONObject;
- import java.util.List;
- import java.util.Map;
- /**
- * Servlet implementation class DataLoad
- */
- public class DataLoad extends HttpServlet {
- private static final long serialVersionUID = 1L;
- static class Person {
- private long id;
- private String firstName;
- private String lastName;
- public long getId() {
- return id;
- }
- public void setId(long id) {
- this.id = id;
- }
- public String getFirstName() {
- return firstName;
- }
- public void setFirstName(String firstName) {
- this.firstName = firstName;
- }
- public String getLastName() {
- return lastName;
- }
- public void setLastName(String lastName) {
- this.lastName = lastName;
- }
- public boolean match(String pattern) {
- return firstName.contains(pattern) || lastName.contains(pattern) || Long.toString(id).contains(pattern);
- }
- }
- private static Random r = new Random();
- private static List<Person> ps = new ArrayList<Person>();
- static {
- int size = 2512;
- for (int k = 0; k < size; ++k)
- ps.add(generatePerson());
- }
- static Person generatePerson() {
- Person p = new Person();
- p.setId(ps.size() + 1);
- p.setFirstName(generateName());
- p.setLastName(generateName());
- return p;
- }
- private static String generateName() {
- StringBuilder sb = new StringBuilder();
- sb.append((char) (r.nextInt(26) + 'A'));
- int len = 2 + r.nextInt(4);
- for (int k = 0; k < len; ++k)
- sb.append((char) (r.nextInt(26) + 'a'));
- return sb.toString();
- }
- private List<Person>result;
- public List<Person>getResult(){
- return result;
- }
- /**
- * @see HttpServlet#HttpServlet()
- */
- public DataLoad() {
- super();
- }
- /**
- * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
- * response)
- */
- protected void doGet(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- int start=0;
- int length=10;
- String pattern="";
- String draw="1";
- Map<String,String[]>params=request.getParameterMap();
- for(String attr:params.keySet()){
- String[] val=params.get(attr);
- System.out.println(attr+"="+Arrays.toString(val));
- if(attr.equals("start"))
- start=Integer.parseInt(val[0]);
- if(attr.equals("length"))
- length=Integer.parseInt(val[0]);
- if(attr.equals("search[value]"))
- pattern=val[0];
- if(attr.equals("draw"))
- draw=val[0];
- }
- int total=filter(start, length, pattern);
- JSONObject obj = new JSONObject();
- obj.put("draw", draw);
- obj.put("recordsTotal", ps.size());
- obj.put("recordsFiltered", total);
- System.out.println(obj.toJSONString());
- obj.put("data", result);
- response.getWriter().println(obj.toJSONString());
- }
- /**
- * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
- * response)
- */
- protected void doPost(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- doGet(request, response);
- }
- private int filter(int start,int length,String pattern){
- result=new LinkedList<Person>();
- int total=0;
- for(Person s:ps){
- if(!s.match(pattern))
- continue;
- ++total;
- if(start-->0)
- continue;
- if(length--<=0)
- continue;
- result.add(s);
- }
- return total;
- }
- public static void main(String[] rags) {
- System.out.println(JSON.toJSONString(ps));
- DataLoad load=new DataLoad();
- load.filter(0, 10, "");
- System.out.println(JSON.toJSONString(load.getResult()));
- load.filter(0, 10, "a");
- System.out.println(JSON.toJSONString(load.getResult()));
- load.filter(10, 10, "a");
- System.out.println(JSON.toJSONString(load.getResult()));
- load.filter(20, 10, "a");
- System.out.println(JSON.toJSONString(load.getResult()));
- }
- }
服务端返回的JSON数据如下所示。其中draw是请求中的draw参数,data是表格中的数据。recordsFiltered是过滤后的数据总数,recordsTotal是原始数据总数。
- {"recordsFiltered":2512,
- "data":[{"firstName":"Bzf","id":1,"lastName":"Hazkm"},{"firstName":"Imxi","id":2,"lastName":"Oieb"},{"firstName":"Glyag","id":3,"lastName":"Gvqlf"},{"firstName":"Lwbhl","id":4,"lastName":"Fvvf"},{"firstName":"Audds","id":5,"lastName":"Seunp"},{"firstName":"Otbrq","id":6,"lastName":"Hnal"},{"firstName":"Loji","id":7,"lastName":"Qicn"},{"firstName":"Rjy","id":8,"lastName":"Emrygr"},{"firstName":"Gcglkd","id":9,"lastName":"Ldgrs"},{"firstName":"Txh","id":10,"lastName":"Qwe"}],
- "draw":"1",
- "recordsTotal":2512}
返回数据后,网页如下所示。