AJAX displays data in JSON format. The hql statement query corresponds to a class.

Front-End Interface

<% @ Page language = "java" import = "java. util. *" pageEncoding = "UTF-8" %>
<% @ Taglib uri = "http://java.sun.com/jsp/jstl/core" prefix = "c" %>
<%
String path = request. getContextPath ();
String basePath = request. getScheme () + ": //" + request. getServerName () + ":" + request. getServerPort () + path + "/";
%>







My JSP 'index. jsp 'starting page





<Script type = "text/javascript" src = "js/jquery-1.9.1.js"> </script>
<Script type = "text/javascript">
Function showplus (provinceid ){
// Four parameters need to be passed
// 1: Submission path; 2: Passing parameters using objects. Each parameter is passed as an attribute of objects.
// 3: callback function 4: data type. You can select text, xml, or json format.
$. Post ("<% = basePath %> province_showplus.action", {provinceid: provinceid}, showplusCallback, "json ");
}
// JQuery automatically converts the returned string to an object or array and returns the string directly using the callback function parameters.
Function showplusCallback (array ){

// Use the selector to retrieve the drop-down list object
Var citySelect = $ ("# city ");
// Locate the page element to be deleted and call the delete operation
$ ("# City option: gt (0)"). remove (); // avoid overlapping cities under the province selected next time
// Cyclically obtain the id and cname
For (var I = 0; I var cid = array [I]. cid;
Var cname = array [I]. cname;
// JQuery creates page elements and concatenates them directly using strings.
Var option =""+ Cname +"";
// Set option to a subnode of city select
CitySelect. append (option );
}
}
</Script>


Test it.


-- Select -- $ {P. pname}
-- Select --

Action class

Package com. kane. action;
Import java. io. PrintWriter;
Import java. util. Iterator;
Import java. util. List;
Import javax. servlet. http. HttpServletResponse;
Import org. apache. struts2.ServletActionContext;
Import org. json. JSONArray;
Import org. json. JSONObject;
Import com. kane. pojo. City;
Import com. kane. pojo. Province;
Import com. kane. service. IProvinceService;
Import com. opensymphony. xwork2.ActionSupport;


Public class ProvinceAction extends ActionSupport {
Private IProvinceService provinceServiceImpl;
Private List AllProvince;
Public List GetAllProvince (){
Return allProvince;
}
Public void setAllProvince (List AllProvince ){
This. allProvince = allProvince;
}
Public int getProvinceid (){
Return provinceid;
}
Public void setProvinceid (int provinceid ){
This. provinceid = provinceid;
}
Private int provinceid;
Public IProvinceService getProvinceServiceImpl (){
Return provinceServiceImpl;
}
Public void setProvinceServiceImpl (IProvinceService provinceServiceImpl ){
This. provinceServiceImpl = provinceServiceImpl;
}

// Click test. Enter the action first.
Public String indexPre () throws Exception {
AllProvince = provinceServiceImpl. findAll ();

Return "index ";
}
/**
* AJAX call method, return null,
*
* @ Return
* @ Throws Exception
*/
Public String showplus () throws Exception {
// Json String concatenation, high efficiency of single-thread stringbuffer and high efficiency of multi-thread stringbuilder
StringBuilder sBuilder = new StringBuilder ();
List List = provinceServiceImpl. showplus (provinceid );
Iterator Iter = list. iterator ();
/* SBuilder. append ("[");

Int index = 0;
While (iter. hasNext ()){
City city = iter. next ();
If (index> 0 ){
SBuilder. append (","); // except the first one, each object is preceded by a comma
}
SBuilder. append ("{'cid':" + city. getCid ());
SBuilder. append (",");
SBuilder. append ("'cname': '" + city. getCname () + "'");
SBuilder. append ("}");
Index ++;
}
SBuilder. append ("]"); */

// Use the class provided by the org. json package to spell the content
// Create an array
JSONArray array = new JSONArray ();

While (iter. hasNext ()){
City c = iter. next ();
JSONObject obj = new JSONObject ();
// Set attributes for the object, similar to Map
Obj. put ("cid", c. getCid ());
Obj. put ("cname", c. getCname ());
Array. put (obj );
}
HttpServletResponse response = ServletActionContext. getResponse ();
// Set the encoding to prevent garbled data
Response. setCharacterEncoding ("UTF-8 ");
Response. setContentType ("text/html"); // This method is used for strings and json. xml uses text/xml
// Printwriter must be used to write data to the foreground.
PrintWriter out = response. getWriter ();
Out. print (array); // The array corresponds to the parameters of the foreground callback function.
Out. close (); // step 4 of ajax
Return null;
}
}

Action configuration file

Xmlns: xsi = "http://www.w3.org/2001/XMLSchema-instance" xmlns: p = "http://www.springframework.org/schema/p"
Xsi: schemaLocation = "http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

Display result

DaoImpl

Package com. kane. dao. Impl; <喎?http: www.bkjia.com kf ware vc " target="_blank" class="keylink"> Signature + signature + CnB1YmxpYyBMaXN0PENpdHk + IGZpbmRCeUlkKEludGVnZXIgaWQpIHRocm93cyBFeGNl CHRpb24gewo8YnI + ClN0cmluZyBocWw9 "FROM City AS c WHERE c. province. pid =? "; // Corresponds to the pojo class
List All = super. getHibernateTemplate (). find (hql, id );
Return all;
}


}

// Click the province to display the corresponding city list

To create a test case, You must select testcase 4.0 when creating a test case.

ServiceImpl

Package com. kane. service. Impl;
Import java. util. HashMap;
Import java. util. List;
Import java. util. Map;
Import com. kane. dao. ICity;
Import com. kane. dao. IProvince;
Import com. kane. pojo. City;
Import com. kane. pojo. Province;
Import com. kane. service. IProvinceService;
/**
* AOP solves preprocessing and disconnection.
* @ Author lenovo
*
*/
Public class ProvinceServiceImpl implements IProvinceService {
Private IProvince provinceImpl;
Private ICity cityImpl;
Public ICity getCityImpl (){
Return cityImpl;
}

Public void setCityImpl (ICity cityImpl ){
This. cityImpl = cityImpl;
}


Public IProvince getProvinceImpl (){
Return provinceImpl;
}


Public void setProvinceImpl (IProvince provinceImpl ){
This. provinceImpl = provinceImpl;
}

Public void delete (int id) throws Exception {
// TODO Auto-generated method stub

}


Public void insert (Province pro) throws Exception {
// TODO Auto-generated method stub

}

Public List InsertPre () throws Exception {
// TODO Auto-generated method stub
Return null;
}

Public Map List (int pageNo, int pageSize, String keyword,
String column) throws Exception {
Map Map = new HashMap ();
Map. put ("allProvince", provinceImpl. findByPage (pageNo, pageSize, column, keyword ));
Map. put ("allCount", provinceImpl. getCount (column, keyword ));
Return map;
}


Public List Showplus (int pid) throws Exception {
List List = cityImpl. findById (pid );
Return list;
}
}