How to click a link in webpage through groovyscript using soapui tool.

I would recommend you to have a look at the Geb framework.

I think it can do almost exactly what you want it to. 

@Grapes([
   @Grab("org.codehaus.geb:geb-core:0.7.0"),
   @Grab("org.seleniumhq.selenium:selenium-firefox-driver:2.15.0"),
   @Grab("org.seleniumhq.selenium:selenium-support:2.15.0")
])
import geb.Browser
 
Browser.drive {
    go "http://myapp.com/login"
     
    assert $("h1").text() == "Please Login"
     
    $("form.login").with {
        username = "admin"
        password = "password"
        login().click()
    }
     
    assert $("h1").text() == "Admin Section"
}

For more in-depth guidance i can strongly recommend their online docs