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" : 'https://img.qb5200.com/download-x/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~
精彩专题分享：jquery分页功能操作 JavaScript分页功能操作
