spring 事务传播机制总结

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渭城朝雨浥轻尘 2022-08-16 10:37:35 博主文章分类：Spring ©著作权

文章标签 spring事务事务传播机制事务传播 spring 回滚 文章分类 后端开发

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spring事务的传播机制定义在 TransactionDefinition 接口中，定义了如下传播类型

PROPAGATION_REQUIRED

支持当前事务，如果没有当前事务就创建一个新的事务，是默认的传播行为。

外围方法未开启事务

内部会创建新事务，若新事务回滚，不影响外围方法。

外围方法开启事务

内部方法会加入到外围方法的事务中，使用同一个事务，不管内外谁发生异常，整个事务都将回滚。

/**
   * Support a current transaction; create a new one if none exists.
   * Analogous to the EJB transaction attribute of the same name.
   * <p>This is typically the default setting of a transaction definition,
   * and typically defines a transaction synchronization scope.
   */
  int PROPAGATION_REQUIRED = 0;

PROPAGATION_SUPPORTS

支持当前事务，如果没有事务就以非事务方式执行。

外围方法未开启事务

以非事务方法运行。

外围方法开启事务

内部方法会加入到外围方法的事务中，使用同一个事务，不管内外谁发生异常，整个事务都将回滚。

/**
   * Support a current transaction; execute non-transactionally if none exists.
   * Analogous to the EJB transaction attribute of the same name.
   * <p><b>NOTE:</b> For transaction managers with transaction synchronization,
   * {@code PROPAGATION_SUPPORTS} is slightly different from no transaction
   * at all, as it defines a transaction scope that synchronization might apply to.
   * As a consequence, the same resources (a JDBC {@code Connection}, a
   * Hibernate {@code Session}, etc) will be shared for the entire specified
   * scope. Note that the exact behavior depends on the actual synchronization
   * configuration of the transaction manager!
   * <p>In general, use {@code PROPAGATION_SUPPORTS} with care! In particular, do
   * not rely on {@code PROPAGATION_REQUIRED} or {@code PROPAGATION_REQUIRES_NEW}
   * <i>within</i> a {@code PROPAGATION_SUPPORTS} scope (which may lead to
   * synchronization conflicts at runtime). If such nesting is unavoidable, make sure
   * to configure your transaction manager appropriately (typically switching to
   * "synchronization on actual transaction").
   * @see org.springframework.transaction.support.AbstractPlatformTransactionManager#setTransactionSynchronization
   * @see org.springframework.transaction.support.AbstractPlatformTransactionManager#SYNCHRONIZATION_ON_ACTUAL_TRANSACTION
   */
  int PROPAGATION_SUPPORTS = 1;

PROPAGATION_MANDATORY

mandatory是强制的意思，支持当前事务，如果没有事务，就抛出一个异常

外围方法未开启事务

抛出一个异常。

外围方法开启事务

内部方法会加入到外围方法的事务中，使用同一个事务，不管内外谁发生异常，整个事务都将回滚。

/**
   * Support a current transaction; throw an exception if no current transaction
   * exists. Analogous to the EJB transaction attribute of the same name.
   * <p>Note that transaction synchronization within a {@code PROPAGATION_MANDATORY}
   * scope will always be driven by the surrounding transaction.
   */
  int PROPAGATION_MANDATORY = 2;

PROPAGATION_REQUIRES_NEW

不管当前是否存在事务，都创建一个新事务，如果存在事务，将当前事务暂停(挂起)

外围方法未开启事务

内部会创建新事务，若内部事务回滚，不影响外围方法。

外围方法开启事务

内部方法依然会单独开启独立事务，且与外部方法事务也独立，内部方法之间、内部方法和外部方法事务均相互独立，互不干扰。

代码验证REQUIRES_NEW事务传播机制

/**
   * Create a new transaction, suspending the current transaction if one exists.
   * Analogous to the EJB transaction attribute of the same name.
   * <p><b>NOTE:</b> Actual transaction suspension will not work out-of-the-box
   * on all transaction managers. This in particular applies to
   * {@link org.springframework.transaction.jta.JtaTransactionManager},
   * which requires the {@code jakarta.transaction.TransactionManager} to be
   * made available it to it (which is server-specific in standard Jakarta EE).
   * <p>A {@code PROPAGATION_REQUIRES_NEW} scope always defines its own
   * transaction synchronizations. Existing synchronizations will be suspended
   * and resumed appropriately.
   * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager
   */
  int PROPAGATION_REQUIRES_NEW = 3;

PROPAGATION_NOT_SUPPORTED

不支持事务，不管当前是否存在事务都以非事务方式执行。

外围方法未开启事务

以非事务方式执行。

外围方法开启事务

以非事务方式执行。

/**
   * Do not support a current transaction; rather always execute non-transactionally.
   * Analogous to the EJB transaction attribute of the same name.
   * <p><b>NOTE:</b> Actual transaction suspension will not work out-of-the-box
   * on all transaction managers. This in particular applies to
   * {@link org.springframework.transaction.jta.JtaTransactionManager},
   * which requires the {@code jakarta.transaction.TransactionManager} to be
   * made available it to it (which is server-specific in standard Jakarta EE).
   * <p>Note that transaction synchronization is <i>not</i> available within a
   * {@code PROPAGATION_NOT_SUPPORTED} scope. Existing synchronizations
   * will be suspended and resumed appropriately.
   * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager
   */
  int PROPAGATION_NOT_SUPPORTED = 4;

PROPAGATION_NEVER

不支持事务，如果存在事务，会抛出一个异常

外围方法未开启事务

以非事务方式执行。

外围方法开启事务

抛出一个异常。

/**
   * Do not support a current transaction; throw an exception if a current transaction
   * exists. Analogous to the EJB transaction attribute of the same name.
   * <p>Note that transaction synchronization is <i>not</i> available within a
   * {@code PROPAGATION_NEVER} scope.
   */
  int PROPAGATION_NEVER = 5;

PROPAGATION_NESTED

如果存在当前事务，则在嵌套事务中执行，如果不存在事务，则和PROPAGATION_REQUIRED一样，会新建一个事务。

外围方法未开启事务

与Propagation.REQUIRED 作用相同，内部会创建新事务，若内部事务回滚，不影响外围方法。

外围方法开启事务

修饰的内部方法属于外部事务的子事务，外围主事务回滚，子事务一定回滚，而内部子事务可以单独回滚而不影响外围主事务和其他子事务。

/**
   * Execute within a nested transaction if a current transaction exists,
   * behave like {@link #PROPAGATION_REQUIRED} otherwise. There is no
   * analogous feature in EJB.
   * <p><b>NOTE:</b> Actual creation of a nested transaction will only work on
   * specific transaction managers. Out of the box, this only applies to the JDBC
   * {@link org.springframework.jdbc.datasource.DataSourceTransactionManager}
   * when working on a JDBC 3.0 driver. Some JTA providers might support
   * nested transactions as well.
   * @see org.springframework.jdbc.datasource.DataSourceTransactionManager
   */
  int PROPAGATION_NESTED = 6;