Welcome to the JavaRanch. While you are waiting for an answer, please take the time to read our FAQ, HowToAskQuestionsOnJavaRanch. The better question you ask, the more help we can be. I added CodeTags to your post so it is easier to read.
Your question can use some clarification. You say "I want to update only those values which are selected in display page in struts2". I don't know what that means. Do you want to update only fields that have changed? Do you want to track which fields the user clicked on? How do you "select" a field?