Struts2 + jquery + JSON for AJAX requests __JS

The project wants to use Ajax, so in the online grilled n More information, made a lot of errors, from today's work to now has been dealing with this problem, and finally to solve it.

When I see the AJAX display of the page, I am excited about the exception, in order to record their learning Ajax process, but also in order to make more people less detours, close-up of this article to remember.

Nonsense not to say, in order to better understand, I redo a small project to deepen the impression. Let's start our Ajax tour with this little project now.

First step: Create a Java Web project called Ajax.

Step Two: Add the Struts2 jar pack, which requires four packages Freemarker.jar Ognl.jar Struts2-core.jar Commons-fileupload.jar Commons-io.jar -2.1.6.jar (This package plus version number, because it is mentioned below), these six packages are struts must rely on the jar package, what to say.

Step three: Modify the Web.xml join struts filter, the code is as follows:

<?xml version= "1.0" encoding= "UTF-8"?> <web-app version= "2.5" xmlns= "Http://java.sun.com/xml/ns/javaee" Xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance" xsi:schemalocation= "Http://java.sun.com/xml/ns/javaee http ://java.sun.com/xml/ns/javaee/web-app_2_5.xsd "> <filter> <filter-name>struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class> </filter> < filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </ filter-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </ Welcome-file-list> </web-app>

Fourth step: Add the JSON package, here need two: Json-lib.jar Jsonplugin.jar here to pay attention to a very important point, because JSON a large number of references to the Apache Commons package, so here to join, the need for a total of 4 Commons package,  In addition to the Commons package, you need to introduce a ezmorph package, so this step involves the introduction of 7 packages, listed below: Commons-collections.jar Commons-lang.jar Commons-beanutils.jar Commons-logging.jar Ezmorph.jar plus two packets of JSON with a total of seven, one-time join.

Fifth step: Write the background processing ajaxloginaction.action, the contents are as follows:

Package qy.test.action; Import Java.util.HashMap; Import Java.util.Map; Import Net.sf.json.JSONObject; Import Com.opensymphony.xwork2.ActionSupport; public class Ajaxloginaction extends Actionsupport {//user Ajax returns data private String result;//Struts Property-driven mode, automatically populate page properties to here PR Ivate String LoginName; private String password; @Override public String Execute () {//Use a map as an example map<string, string> map = new hashmap<string, string> (); Map to add a piece of data, record the page passed LoginName map.put ("name", This.loginname); The map object that will be returned is JSON-processed jsonobject JO = jsonobject.fromobject (map); The ToString method that invokes the JSON object converts to a string and then assigns a value to result This.result = Jo.tostring (); Can test result System.out.println (This.result); return SUCCESS; }//getter setter Method omitted}

Sixth step: Write the front desk index.jsp, attention to join jquery JS file contents are as follows:

<%@ page language= "java" contenttype= "text/html; Charset=utf-8 "pageencoding=" UTF-8 "%> <! DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "Http://www.w3.org/TR/html4/loose.dtd" >

Step Seventh: Add Struts.xml to the SRC directory and configure the corresponding XML file to provide data for the AJAX request. The code is as follows:

<?xml version= "1.0" encoding= "UTF-8"?> <! DOCTYPE struts Public "-//apache Software foundation//dtd struts Configuration 2.0//en" "http://struts.apache.org/dtds/ Struts-2.0.dtd "> <struts> <package name=" ajax "extends=" Json-default "> <action name=" Ajaxlogin " class= "Qy.test.action.AjaxLoginAction" > <!--return type is json defined in Sjon-default--> <result type= "JSON" > <! --The value of the root corresponds to the property of the value to be returned--> <!--The result value here is the result in the corresponding action--> <param name= "root" >result</param> & lt;/result> </action> </package> </struts>

Eighth step: If the fourth step does not join the Commons-logging.jar package, please remember to join

Nineth Step: Publish Run. Unfortunately, you will find a mistake,

Java.lang.ClassNotFoundException:com.opensymphony.xwork2.util.TextUtils:

This is a version of struts error because there is no textutils class in the Xwork2.1.6-core.jar, where the Xwork2.1.2-core.jar also added to the Classpath, Xwork2.1.2-core.jar contains this thing, we use the jar of xwork2.1.6, when you want to use Textutils, go to Xwork2.1.2-core.jar to find.