Shulou(Shulou.com)06/02 Report--

How to understand Spring Hibernate transaction management mechanism, for this problem, this article describes the corresponding analysis and solution in detail, hoping to help more small partners who want to solve this problem find a simpler and easier way.

Spring declarative transactions are a relief from the complexity of Hibernate transactions.

This eliminates the need to deal with getting connections, closing connections, Hibernate transaction commits, and rolling back. have nothing more to be

requires us to handle a lot of try…catch…finally code in transaction-related methods

。

A very important concept when we use Spring declarative transactions is transaction attributes. Transaction attributes typically consist of the propagation behavior of the transaction, the isolation level of the transaction, the timeout value of the transaction, and the transaction read-only flag. When we partition transactions, we need to define Hibernate transactions, that is, configure the attributes of Hibernate transactions.

Spring Hibernate defines these properties in the>TransactionDefinition interface for use by PlatfromTransactionManager, the core interface for Spring Hibernate transaction management.

code

TransactionDefinition publicinterfaceTransactionDefinition { intgetPropagationBehavior(); intgetIsolationLevel(); intgetTimeout(); booleanisReadOnly(); }

getTimeout() method, which returns how many seconds the transaction must complete.

isReadOnly(), whether the transaction is read-only, the transaction manager can optimize based on this return value to ensure that the transaction is read-only.

The getIsolationLevel() method returns the isolation level of the transaction by which the transaction manager controls what data within the transaction is visible to another transaction.

Five different transaction isolation levels are defined in the TransactionDefinition interface:

1)ISOLATION_DEFAULT This is a PlatfromTransactionManager default isolation level that uses the database default transaction isolation level. The other four correspond to JDBC isolation levels

2)ISOLATION_READ_UNCOMMITTED This is the isolation level of transaction ***, which allows another transaction to see the uncommitted data of this transaction. This isolation level produces dirty reads, non-repeatable reads, and phantom reads.

3)ISOLATION_READ_COMMITTED ensures that data modified by one transaction is committed before it can be read by another transaction. Another transaction cannot read uncommitted data from this transaction. This level of transaction isolation prevents dirty reads from occurring, but non-repeatable reads and phantom reads may occur.

4)ISOLATION_REPEATABLE_READ This level of transaction isolation prevents dirty reads from being repeated. But there may be phantom readings. In addition to ensuring that one transaction cannot read uncommitted data from another transaction, it also ensures that the following conditions are avoided (non-repeatable reads)

Seven transaction propagation behaviors are defined in the TransactionDefinition interface:

1)

PROPAGATION_REQUIRED Supports the current transaction if one exists. if there is no transaction, a new transaction is started;

2)PROPAGATION_SUPPORTS Supports the current transaction if one exists. If there is no transaction, execution of the non-transaction;

3)PROPAGATION_MANDATORY Supports the current transaction if one already exists. If there is no active transaction, throw an exception;

PROPAGATION_REQUIRES_NEW always opens a new transaction. If a transaction already exists, suspend the existing transaction;

5)PROPAGATION_NOT_SUPPORTED always executes non-transactionally and suspends any existing transactions;

6)PROPAGATION_NEVER always executes non-transactionally, throwing an exception if there is an active transaction;

7)PROPAGATION_NESTED Runs in a nested transaction if an active transaction exists. If there is no active transaction, execute by TransactionDefinition.PROPAGATION_REQUIRED attribute;

About how to understand the Spring Hibernate transaction management mechanism to share the answer to the problem here, I hope the above content can be of some help to everyone, if you still have a lot of doubts not solved, you can pay attention to the industry information channel to learn more related knowledge.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.