How to detect submit button clicked in multiple submit buttons scenario in single Action class?

I have a form in a jsp. There are two submit buttons: "Search" and "Add New" button.

<s:form name="searchForm" action="employeeAction" method="post">
    <s:textfield name="id" label="Employee ID"/>
    <s:textfield name="name" label="Employee Name"/>

    <s:submit value="Search"/>
    <s:submit value="Add New"/>
</s:form>

In struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>

    <constant name="struts.enable.DynamicMethodInvocation" value="false" />
    <constant name="struts.devMode" value="true" />

    <package name="default" namespace="/" extends="struts-default">

        <default-action-ref name="index" />

        <global-results>
            <result name="error">/error.jsp</result>
        </global-results>

        <global-exception-mappings>
            <exception-mapping exception="java.lang.Exception" result="error"/>
        </global-exception-mappings>

    </package>

    <package name="example" namespace="/example" extends="default">

        <action name="employeeAction" class="example.EmployeeAction">
           <result name="search">/example/search.jsp</result>
           <result name="add" type="redirect">/example/add.jsp</result>
        </action>

    </package>
</struts>

In Struts Action class, we know that there is only one method that processing http request, that is execute() method.

In my expected case, when I clicked Search button, it will perform searching data and render data to /example/search.jsp, when I clicked Add New button, it will perform redirecting page to /example/add.jsp. However, both buttons when clicked will go into execute() method. So I need to know how to detect which button clicked in the execute() method.

The scenario looks like this

public class EmployeeAction extends ActionSupport {

    public String execute() throws Exception {

        //PSEUDOCODE
        //IF (submitButton is searchButton) 
        //    return doSearch();
        //ELSE IF (submitButton is addNewButton) 
        //    return doAddNew();

        return SUCCESS;
    }

    public String doSearch() throws Exception {
        //perform search logic here
        return "search";
    }

    public String doAddNew() throws Exception {
        return "add";
    }
}

Solution

You can define two actions in struts.xml file and use action attribute of <s:submit> tag in order to submit to different actions http://struts.apache.org/docs/submit.html.

In JSP:

<s:submit value="Search" action="searchEmployeeAction"/>
<s:submit value="Add New" action="addEmployeeAction"/>

In struts.xml:

<action name="addEmployeeAction" method="add" class="example.EmployeeAction">
    <result>/example/add.jsp</result>
</action>

<action name="searchEmployeeAction" method="search" class="example.EmployeeAction">
    <result>/example/search.jsp</result>
</action>

And in your action create two public String methods add and search.

Read about Multiple Submit Buttons http://struts.apache.org/docs/multiple-submit-buttons.html.

Update

Starting from Struts2 version 2.3.15.3 you need to set struts.mapper.action.prefix.enabled constant to true in order to enable support for action: prefix.

Put that in your struts.xml file:

<constant name="struts.mapper.action.prefix.enabled" value="true" />