Unable to implement Struts 2 token interceptor with hyperlink

Question

I tried to implement token interceptor with the tag but its showing error on the first click. i.e The form has already been processed or

Answer 1

The s:token tag merely places a hidden element that contains the unique token.

There's not need to use token with url, because the form should be submitted. If you want to pass some token as a parameter then you need to use s:param tag.

Define the parameter

  private String token;

  public String getToken() {
    return token;
  }

  public void setToken(String token) {
    this.token = token;
  }

  public String execute() throws Exception {
    Map<String, Object> context = ActionContext.getContext().getValueStack().getContext();
    Object myToken = context.get("token");
    if (myToken == null) {
        myToken = TokenHelper.setToken("token");
        context.put("token", myToken);
    }
    token = myToken.toString();
    return SUCCESS;
  }

in the JSP

<s:url var="linkdelete" namespace="/admin/insecure/upload" action="DeleteLatestUpload" ><s:param name="struts.token.name" value="%{'token'}"/><s:param name="token" value="%{token}"/></s:url>

Answer 2

The most simple way to use token with url is to use <s:token/> tag to set token value into session and retrieve it in <s:param> tag.

<s:token/>

<s:url var="..." action="...">
  <s:param name="struts.token.name" value="'token'"/>
  <s:param name="token" value="#session['struts.tokens.token']"/>
</s:url>