不配置rollbackFor的情况：默认抛出RuntimeExeception时会回滚

配置rollbackFor的情况：按抛出的异常进行捕捉回滚

参考文档org.springframework.transaction.annotation.Transactional

/**
 * Describes transaction attributes on a method or class.
 *
 * <p>This annotation type is generally directly comparable to Spring's
 * {@link org.springframework.transaction.interceptor.RuleBasedTransactionAttribute}
 * class, and in fact {@link AnnotationTransactionAttributeSource} will directly
 * convert the data to the latter class, so that Spring's transaction support code
 * does not have to know about annotations. If no rules are relevant to the exception,
 * it will be treated like
 * {@link org.springframework.transaction.interceptor.DefaultTransactionAttribute}
 * (rolling back on runtime exceptions).
 *
 * <p>For specific information about the semantics of this annotation's attributes,
 * consider the {@link org.springframework.transaction.TransactionDefinition} and
 * {@link org.springframework.transaction.interceptor.TransactionAttribute} javadocs.
 *
 * @author Colin Sampaleanu
 * @author Juergen Hoeller
 * @since 1.2
 * @see org.springframework.transaction.interceptor.TransactionAttribute
 * @see org.springframework.transaction.interceptor.DefaultTransactionAttribute
 * @see org.springframework.transaction.interceptor.RuleBasedTransactionAttribute
 */