extract accountId from User set as "user" property at session scope

UserAccountIdExtractor.java

package org.example;

import java.io.Serializable;

import org.springframework.social.web.connect.AccountIdExtractor;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.WebRequest;

// your own User class
import org.example.User;

/**
 * extract accountId from User set as "user" property at session scope
 */
public class UserAccountIdExtractor implements AccountIdExtractor {

	@Override
	public Serializable extractAccountId(final WebRequest request) {
		User user = (User) request.getAttribute("user", RequestAttributes.SCOPE_SESSION);
		return user == null ? null : user.getId();
	}

}