我想在 JAVA 的 FOR 循环之外使用一个变量

Question

I have a String which I want to use as a parameter in a query. My code is as follows:

List<EventPayload> mylist=eventpojo.getEventPayload();

            for(EventPayload array : mylist)
            {
                System.out.println("Comment Text :"+array.getCommentText());
                System.out.println("Comment Type :"+array.getCommentType());
                System.out.println("Comment Id :"+array.getCommentId());
                System.out.println("Email id :"+array.getComment_email());
                String email1=array.getComment_email();
            }

            EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("jcg-JPA");
            EntityManager em = entityManagerFactory.createEntityManager();

            String email=em.createQuery("SELECT user_id FROM UserInfo WHERE email_id = "+email1).toString();

I want to use String email1 outside the loop in the query.How to implement this??

Answer 1

email1 is inside the forloop so the scope is reduced to that segment...

declaring that outside, will set the scope of the variable to be accessable outside too...

List<EventPayload> mylist=eventpojo.getEventPayload();
String email1=null;  //HERE!!
for(EventPayload array : mylist)
{
    System.out.println("Comment Text :"+array.getCommentText());
    System.out.println("Comment Type :"+array.getCommentType());
    System.out.println("Comment Id :"+array.getCommentId());
    System.out.println("Email id :"+array.getComment_email());
    email1=array.getComment_email();
}

EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("jcg-JPA");
EntityManager em = entityManagerFactory.createEntityManager();

String email=em.createQuery("SELECT user_id FROM UserInfo WHERE email_id = "+email1).toString();

Answer 2

short answer: you can't

long answer/further question: What do you want to to?

Fire a SQL for each EventPayload -> then do this in the loop

Fire a SQL for one distinct EventPayload -> look in the list for the object (or filter the list) and execute the query for this object