29 July, 2012

example of ajax using struts2

----------------------- web.xml---------------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_9" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <display-name>Java</display-name>
    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</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>


----------------------- index.jsp---------------------------------------
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<script type="text/javascript">
    function get_random(){
        var ranNum= Math.floor(Math.random()*5);
        return ranNum;
    }
</script>
<head>
    <META HTTP-EQUIV="Refresh" CONTENT="0;URL=example/showHomePage.action?rand=<%=(Math.random()) %>">
</head>
<body>
<p>Loading ...</p>
</body>
</html>



--------------------- struts.xml---------------------------------
<?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>
    <constant name="struts.enable.DynamicMethodInvocation" value="false" />
    <constant name="struts.devMode" value="false" />
    <package name="example" namespace="/example" extends="struts-default">
        <action name="showHomePage" class="example.Login">
            <result>/example/LoginPage.jsp</result>
        </action>
        <action name="validateUsername" class="example.Login" method="validateUsername">
            <result>/example/resp.jsp</result>
            <result name="input">/example/resp.jsp</result>
        </action>
    </package>
</struts> 


------------------ LoginPage.jsp
------------------------------
<%@ page contentType="text/html; charset=UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<html>
<head>
    <script type="text/javascript">
        var xmlhttp;
        function getHTTPObjectForBrowser(){
            if (window.XMLHttpRequest){
                  xmlhttp=new XMLHttpRequest();
            }else{
                  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
            }
            return xmlhttp;
        }
        function setAjaxOutput(){
            if(xmlhttp.readyState == 4){
                var result = xmlhttp.responseText;
                if(result=='input'){
                    document.getElementById('username').value='';
                    document.getElementById('password').value='';
                    document.getElementById('username').focus();
                }
                if(result=='success'){
                    document.getElementById('result').value=result;
                }
            }
        }
        function validateUser(){
            xmlhttp= getHTTPObjectForBrowser();
            var username = document.getElementById('username').value;
            var password = document.getElementById('password').value;
           
            if (xmlhttp!= null) {
                var url = "validateUsername.action?username="+username+'&password='+password;
                xmlhttp.open("GET", url, true);
                xmlhttp.send(null);
                xmlhttp.onreadystatechange = setAjaxOutput;
            }
        }           
    </script>
</head>
<body>
    <s:form name="loginPage" id="LoginPage" action="loginSubmit">
        <s:textfield label="username" id="username"> </s:textfield>
        <s:textfield label="password" id="password" onblur="validateUser();"></s:textfield>
        <s:textfield label="result" id="result" name="result"></s:textfield>
    </s:form>
</body>
</html>
 


-------------------------- Login.java---------------------------
import com.opensymphony.xwork2.ActionSupport;
public class Login extends ActionSupport {
    private static final long serialVersionUID = 1L;
    private String username;
    private String password;
    private String resp;

    public String execute() {
        return SUCCESS;
    }

    public String validateUsername() {
        if (username.equals("admin") && password.equals("admin")) {
            resp = "success";
            return SUCCESS;
        } else {
            resp = "input";
            return INPUT;
        }
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public void setResp(String resp) {
        this.resp = resp;
    }

    public String getResp() {
        return resp;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getPassword() {
        return password;
    }
}


-------------- resp.jsp-------------------------------------
${resp}




Screen shot:
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