事务注解转换器

说白了就是该接口的实现会将@Transactional注解转换成TransactionAttribute，该接口只有一个抽象方法

@Nullable
TransactionAttribute parseTransactionAnnotation(AnnotatedElement ae);

其中SpringTransactionAnnotationParser类是该接口的实现之一，下面以该类作为演示

import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

@Transactional(propagation = Propagation.REQUIRED)
public class Class01 {

  @Transactional(propagation = Propagation.NEVER)
  public void m1() {
  }

  public static void main(String[] args) throws NoSuchMethodException, SecurityException {
    SpringTransactionAnnotationParser tap = new SpringTransactionAnnotationParser();
    Class<?> clazz = Class01.class;
    Method method = Class01.class.getMethod("m1");
    TransactionAttribute ta1 = tap.parseTransactionAnnotation(clazz);
    TransactionAttribute ta2 = tap.parseTransactionAnnotation(method);
    System.out.println(ta1);
    System.out.println(ta2);
  }
}