spring 事务传播与隔离级别DEMO

Propagation.NESTED解释： 内嵌事务依赖于外部事务；若内部事务发生异常则回滚至内部事务开始的位置，继续执行外部事务；若内部事务正常处理完，外部事务发生异常，则外部事务同内部事务一起回滚； 若内部事务正常处理完，则继续进行外部事务，等外部事务处理完，两者一起提交或者一起回滚。 事务的隔离级别: READ_COMMITTED 锁定正在读取的行 REPEATABLE_READ 锁定读取的所有行 SERIALIZABLE 锁表 /** * Use the default isolation level of the underlying datastore. * All other levels correspond to the JDBC isolation levels. * @see java.sql.Connection */ DEFAULT(TransactionDefinition.ISOLATION_DEFAULT), /** * A constant indicating that dirty reads, non-repeatable reads and phantom reads * can occur. This level allows a row changed by one transaction to be read by * another transaction before any changes in that row have been committed * (a "dirty read"). If any of the changes are rolled back, the second * transaction will have retrieved an invalid row. * @see java.sql.Connection#TRANSACTION_READ_UNCOMMITTED */ READ_UNCOMMITTED(TransactionDefinition.ISOLATION_READ_UNCOMMITTED), /** * A constant indicating that dirty reads are prevented; non-repeatable reads * and phantom reads can occur. This level only prohibits a transaction * from reading a row with uncommitted changes in it. * @see java.sql.Connection#TRANSACTION_READ_COMMITTED */ READ_COMMITTED(TransactionDefinition.ISOLATION_READ_COMMITTED), /** * A constant indicating that dirty reads and non-repeatable reads are * prevented; phantom reads can occur. This level prohibits a transaction * from reading a row with uncommitted changes in it, and it also prohibits * the situation where one transaction reads a row, a second transaction * alters the row, and the first transaction rereads the row, getting * different values the second time (a "non-repeatable read"). * @see java.sql.Connection#TRANSACTION_REPEATABLE_READ */ REPEATABLE_READ(TransactionDefinition.ISOLATION_REPEATABLE_READ), /** * A constant indicating that dirty reads, non-repeatable reads and phantom * reads are prevented. This level includes the prohibitions in * <code>ISOLATION_REPEATABLE_READ</code> and further prohibits the situation * where one transaction reads all rows that satisfy a <code>WHERE</code> * condition, a second transaction inserts a row that satisfies that * <code>WHERE</code> condition, and the first transaction rereads for the * same condition, retrieving the additional "phantom" row in the second read. * @see java.sql.Connection#TRANSACTION_SERIALIZABLE */ SERIALIZABLE(TransactionDefinition.ISOLATION_SERIALIZABLE);