OK,上次完成了客户端的分页,这次我们就在上一次的Demo上进行修改,来实现服务端的分页~
js代码:
<script type="text/javascript"> $(document).ready(function() { $('#table_id_example').DataTable({ "bProcessing" : false, //是否显示加载 "sAjaxSource" : '/datatableDemo/user/json', //请求资源路径 "serverSide": true, //开启服务器处理模式 /* 使用ajax,在服务端处理数据 sSource:即是"sAjaxSource" aoData:要传递到服务端的参数 fnCallback:处理返回数据的回调函数 */ "fnServerData": function(sSource, aoData, fnCallback){ $.ajax( { 'type' : 'post', "url": sSource, "dataType": "json", "data": { "aodata" : JSON.stringify(aoData) }, "success": function(resp) { fnCallback(resp); } }); }, "columns" : [ { data : "id" }, { data : "name" }, { data : "age" }, ] }); }) </script>
开启服务器处理模式,这时我们对表格的每次操作,datatable都会帮我们向服务器发起请求获取数据,默认是用GET方式传递参数,所以我们下面加上了”fnServerData”,这样可以修改参数传递的方式为POST,那么到底给服务端发送的”aoData”是个什么鬼呢,别急,我们直接从Servlet取出来看看就知道了
此时我们的Servlet也要做一点修改:
public class Action extends HttpServlet { /** * */ private static final long serialVersionUID = 5957315496919679612L; @Override protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 编码设置 request.setCharacterEncoding("UTF-8"); response.setContentType("text/html; charset=UTF-8"); response.setCharacterEncoding("UTF-8"); // 把传送过来的JSON字符串转成JSON数组 JSONArray ja = JSONArray.fromObject(request.getParameter("aodata")); System.out.println(ja); // 从数据库获取数据 List<User> listUser = Service.getInstance().getAll(); // 数据封装并返回给客户端 DataTableJSONResponse dtjs = new DataTableJSONResponse(listUser); JSONObject jsonObject = JSONObject.fromObject(dtjs); response.getWriter().print(jsonObject.toString()); }
此时我们运行一下,OK,发现所谓的参数长这个模样
[{“name”:”sEcho”,”value”:1}, {“name”:”iColumns”,”value”:3}, {“name”:”sColumns”,”value”:”,,”}, {“name”:”iDisplayStart”,”value”:0}, {“name”:”iDisplayLength”,”value”:10}, {“name”:”mDataProp_0”,”value”:”id”}, {“name”:”sSearch_0”,”value”:”“}, {“name”:”bRegex_0”,”value”:false}, {“name”:”bSearchable_0”,”value”:true}, {“name”:”bSortable_0”,”value”:true}, {“name”:”mDataProp_1”,”value”:”name”}, {“name”:”sSearch_1”,”value”:”“}, {“name”:”bRegex_1”,”value”:false}, {“name”:”bSearchable_1”,”value”:true}, {“name”:”bSortable_1”,”value”:true}, {“name”:”mDataProp_2”,”value”:”age”}, {“name”:”sSearch_2”,”value”:”“}, {“name”:”bRegex_2”,”value”:false}, {“name”:”bSearchable_2”,”value”:true}, {“name”:”bSortable_2”,”value”:true}, {“name”:”sSearch”,”value”:”“}, {“name”:”bRegex”,”value”:false}, {“name”:”iSortCol_0”,”value”:0}, {“name”:”sSortDir_0”,”value”:”asc”}, {“name”:”iSortingCols”,”value”:1}]
是不是感觉有点晦涩难懂,于是本菜上网查了下,勉强是看懂这个鬼东西,接下来就讲解一下几个我们需要的参数:
sEcho:客户端发送请求同时发送过来的一个标识,虽然有什么卵用不知道,不过我们服务端返回的数据中必须带有这个标识,哦,官网的文档里说,服务端取出标识最好转一下转成int,防止XXS攻击(懵逼,暂且不管,我们只知道需要这个就行)
iColumns:列数
iDisplayStart:起始索引
iDisplayLength:显示的行数
{“name”:”mDataProp_0”,”value”:”id”},
{“name”:”sSearch_0”,”value”:”“},
{“name”:”bRegex_0”,”value”:false},
{“name”:”bSearchable_0”,”value”:true},
{“name”:”bSortable_0”,”value”:true}
每一列的参数设置,_0即是第一列,这个我们不管,到下面也是提取列名而已
sSearch:全局搜索字段
iSortCol_0:被排序的列
sSortDir_0:排序方式
完成了参数解读,那么接下来就要提取我们的参数啦~~开工加代码
public class Action extends HttpServlet { /** * */ private static final long serialVersionUID = 5957315496919679612L; @Override protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 编码设置 request.setCharacterEncoding("UTF-8"); response.setContentType("text/html; charset=UTF-8"); response.setCharacterEncoding("UTF-8"); // 把传送过来的JSON字符串转成JSON数组 JSONArray ja = JSONArray.fromObject(request.getParameter("aodata")); System.out.println(ja); // 获取需要的参数值 String sEcho = null; Integer iColumns = null; Integer iDisplayStart = null; Integer iDisplayLength = null; List<String> mDataProp = new ArrayList<String>(); //存放列名 String sSearch = null; Integer iSortCol_0 = null; String iSortCol = null; String sSortDir_0 = null; for (int i = 0; i < ja.size(); i++) { if (ja.getJSONObject(i).getString("name").equals("sEcho")) sEcho = ja.getJSONObject(i).getString("value"); else if (ja.getJSONObject(i).getString("name").equals("iColumns")) iColumns = Integer.valueOf(ja.getJSONObject(i).getString("value")); else if (ja.getJSONObject(i).getString("name").equals("iDisplayStart")) iDisplayStart = Integer.valueOf(ja.getJSONObject(i).getString("value")); else if (ja.getJSONObject(i).getString("name").equals("iDisplayLength")) iDisplayLength = Integer.valueOf(ja.getJSONObject(i).getString("value")); else if (ja.getJSONObject(i).getString("name").equals("sSearch")) sSearch = ja.getJSONObject(i).getString("value"); else if (ja.getJSONObject(i).getString("name").equals("iSortCol_0")) iSortCol_0 = Integer.valueOf(ja.getJSONObject(i).getString("value")); else if (ja.getJSONObject(i).getString("name").equals("sSortDir_0")) sSortDir_0 = ja.getJSONObject(i).getString("value"); else if (iColumns != null) { for (int j = 0; j < iColumns; j++) if (ja.getJSONObject(i).getString("name").equals("mDataProp_" + j)) mDataProp.add(ja.getJSONObject(i).getString("value")); } } iSortCol = mDataProp.get(iSortCol_0); System.out.println(sEcho); System.out.println(iColumns); System.out.println(iDisplayStart); System.out.println(iDisplayLength); System.out.println(sSearch); System.out.println(iSortCol); System.out.println(sSortDir_0); // 从数据库获取数据 List<User> listUser = Service.getInstance().getAll(); // 数据封装并返回给客户端 DataTableJSONResponse dtjs = new DataTableJSONResponse(listUser); JSONObject jsonObject = JSONObject.fromObject(dtjs); response.getWriter().print(jsonObject.toString()); }
好的,加工完毕,这时我们跑一跑看看是不是打出我们要的参数,这里我就不贴出来了,你们自己跑了看,好的发现拿到了我们要的参数,那么接下来可以拼接我们的sql语句了,同时我们要对我们的DataTableJSONResponse进行一下小小的修改,因为这里对于返回的数据也是有参数要求的,那我们就把需要的参数放进去,代码如下:
public class DataTableJSONResponse { Object sEcho; Object iTotalRecords; //查询的记录数 Object iTotalDisplayRecords; //过滤后的记录数 Object aaData; public DataTableJSONResponse() { super(); } public DataTableJSONResponse(Object aaData) { super(); this.aaData = aaData; } public DataTableJSONResponse(Object sEcho, Object iTotalRecords, Object iTotalDisplayRecords, Object aaData) { super(); this.sEcho = sEcho; this.iTotalRecords = iTotalRecords; this.iTotalDisplayRecords = iTotalDisplayRecords; this.aaData = aaData; } public Object getAaData() { return aaData; } public void setAaData(Object aaData) { this.aaData = aaData; } public Object getsEcho() { return sEcho; } public void setsEcho(Object sEcho) { this.sEcho = sEcho; } public Object getiTotalRecords() { return iTotalRecords; } public void setiTotalRecords(Object iTotalRecords) { this.iTotalRecords = iTotalRecords; } public Object getiTotalDisplayRecords() { return iTotalDisplayRecords; } public void setiTotalDisplayRecords(Object iTotalDisplayRecords) { this.iTotalDisplayRecords = iTotalDisplayRecords; } }
完整的Servlet:
public class Action extends HttpServlet { /** * */ private static final long serialVersionUID = 5957315496919679612L; @Override protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 编码设置 request.setCharacterEncoding("UTF-8"); response.setContentType("text/html; charset=UTF-8"); response.setCharacterEncoding("UTF-8"); // 把传送过来的JSON字符串转成JSON数组 JSONArray ja = JSONArray.fromObject(request.getParameter("aodata")); // 获取需要的参数值 String sEcho = null; Integer iColumns = null; Integer iDisplayStart = null; Integer iDisplayLength = null; List<String> mDataProp = new ArrayList<String>(); //存放列名 String sSearch = null; Integer iSortCol_0 = null; String iSortCol = null; String sSortDir_0 = null; for (int i = 0; i < ja.size(); i++) { if (ja.getJSONObject(i).getString("name").equals("sEcho")) sEcho = ja.getJSONObject(i).getString("value"); else if (ja.getJSONObject(i).getString("name").equals("iColumns")) iColumns = Integer.valueOf(ja.getJSONObject(i).getString("value")); else if (ja.getJSONObject(i).getString("name").equals("iDisplayStart")) iDisplayStart = Integer.valueOf(ja.getJSONObject(i).getString("value")); else if (ja.getJSONObject(i).getString("name").equals("iDisplayLength")) iDisplayLength = Integer.valueOf(ja.getJSONObject(i).getString("value")); else if (ja.getJSONObject(i).getString("name").equals("sSearch")) sSearch = ja.getJSONObject(i).getString("value"); else if (ja.getJSONObject(i).getString("name").equals("iSortCol_0")) iSortCol_0 = Integer.valueOf(ja.getJSONObject(i).getString("value")); else if (ja.getJSONObject(i).getString("name").equals("sSortDir_0")) sSortDir_0 = ja.getJSONObject(i).getString("value"); else if (iColumns != null) { for (int j = 0; j < iColumns; j++) if (ja.getJSONObject(i).getString("name").equals("mDataProp_" + j)) mDataProp.add(ja.getJSONObject(i).getString("value")); } } iSortCol = mDataProp.get(iSortCol_0); String sql = null; if(sSearch.equals("")) sql = "select * from(select id,name,age,rownum rn from dtdemo_xxx)" +"where rn between " + iDisplayStart + " and " + (iDisplayStart+iDisplayLength) +" order by " + iSortCol + " " + sSortDir_0; else sql = "select * from(select id,name,to_char(age,999) age,rownum rn from dtdemo_xxx where id like '%" + sSearch +"%' or name like '%"+ sSearch +"%' or age like '%"+ sSearch +"%')" +"where rn between " + iDisplayStart + " and " + (iDisplayStart+iDisplayLength) +" order by " + iSortCol + " " + sSortDir_0; System.out.println(sql); // 从数据库获取数据 List<User> listUser = Service.getInstance().getAll(sql); //获取记录数 int size = Service.getInstance().getAll().size(); // 数据封装并返回给客户端 DataTableJSONResponse dtjs = new DataTableJSONResponse(sEcho,size,size,listUser); JSONObject jsonObject = JSONObject.fromObject(dtjs); response.getWriter().print(jsonObject.toString()); } }
至此,服务端分页完成~
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