Hibernate Validator iterator.hasNext（）无法正常工作

Question

I'm getting an infinite loop with the following code (hasNext() always seems to be true)

 private final ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
 private final Validator validator = factory.getValidator();
 Set<ConstraintViolation<SomeRequest>> reqErrors = validator.validate(request);

 StringBuilder sb = new StringBuilder();
 while(reqErrors.iterator().hasNext()){
       sb.append(reqErrors.iterator().next().getMessage() + "\n");
 }

 errors = sb.toString();

This works fine:

 for(int i = 0; i < reqErrors.size(); i++){
      sb.append(reqErrors.iterator().next().getMessage() + "\n");
 }

What am I missing here?

Answer 1

It's because you are calling (creating) iterator twice !!

Just make it once, at the top and use it.

Iterator iterator = reqErrors.iterator();
while(iterator.hasNext()){
       sb.append(iterator.next().getMessage() + "\n");
}