To invoke java function from velocity template during onclick event

Web application uses struts2 and velocity

The velocity file has a link and when the link is clicked i want java function to be called.

productform.vm

 <a href="javascript:void(0);" onclick="*************" id="acnt_link"> Add Acnt </a>

when the link from velocity file is clicked, i need java function to be called

abc.java

public void printabc(){
syso("Java function called when link from velocity temp is clicked");
}

Please advise on how to do this

i can invoke javascript function when link from velocity is clicked, but from javascript function how can i call the java function(for example abc.printabc())

Please advise.

Solution

You can take a look at DWR which gives you methods from java as javascript function. Directly taken from their Tutorial:

public class Remote {
    public String getData(int index) { ... }
}

And the correspondening html snippet:

<head>
<!-- other stuff -->
<script type="text/javascript" src="[WEBAPP]/dwr/interface/Remote.js"> </script>
<script type="text/javascript" src="[WEBAPP]/dwr/engine.js"> </script>   
<script>
function myRemoteMethod() {
    Remote.getData(42, {
        callback: function(str) { 
            alert(str); 
    }});
}
</script>
</head>
<body>
<!-- ... -->
    <a href="javascript:void(0);" onclick="myRemoteMethod()">Add Acnt</a>
<!-- ... -->
</body>

Make sure you integrate the DWR into struts, they have also tutorials for that: DWR Struts Tutorial.

Another solution would be to call that java method via an ajax request:

function myRemoteMethod() {
    $.get('/link/to/method/')
    .done(function (data) {
         alert('Return message of server was:' + data);
    });
}

This is a jQuery example, so make sure you have the library in the <head> of your html code. Call this method in the html code and you "call" the java method via ajax.

<a href="javascript:void(0);" onclick="myRemoteMethod()">Add Acnt</a>