Another way to manage spring transactions--transactiontemplate programming transaction management simple Getting Started

1, all along, in the management of things with spring, only know the use of declarative policy, that is, according to different data sources, configure a thing manager (TransactionManager), by configuring the Slice (PointCut) Apply to the appropriate business method or add @ttransactional annotations directly to the method.

This kind of transaction management is relatively simple to use, but the personal feeling of flexibility lacks a point.

2, recently looked at the company project Code, found a colleague in his module has used another kind of transaction management method, checked, Transactiontemplate is a programmatic transaction management. You need to implement transactions manually in each business method.

3, transactiontemplate use (not necessarily comprehensive):

A, in the DAO layer configuration file, configuration transactiontemplate, need to inject TransactionManager

　　

    <BeanID= "TransactionManager"class= "Org.springframework.jdbc.datasource.DataSourceTransactionManager">        < Propertyname= "DataSource"ref= "DataSource"/>    </Bean>    <BeanID= "Transactiontemplate"class= "Org.springframework.transaction.support.TransactionTemplate">        < Propertyname= "TransactionManager">            <refBean= "TransactionManager"/>        </ Property>    </Bean>

B, inject transactiontemplate into the business layer method and use:

First analyze the core principles of transactiontemplate:

Transactiontemplate Core Approach:

1  Public classTransactiontemplateextendsdefaulttransactiondefinition2         Implementstransactionoperations, Initializingbean {3 4 5      Public<T> T Execute (transactioncallback<t> action)throwsTransactionException {6         if( This. TransactionManagerinstanceofCallbackpreferringplatformtransactionmanager) {7             return((Callbackpreferringplatformtransactionmanager) This. TransactionManager). Execute ( This, action);8         }9         Else {TenTransactionstatus status = This. Transactionmanager.gettransaction ( This); One T result; A             Try { -result =action.dointransaction (status); -             } the             Catch(RuntimeException ex) { -                 //Transactional code threw application exception-rollback - rollbackonexception (status, ex); -                 Throwex; +             } -             Catch(Error err) { +                 //Transactional code threw error-rollback A rollbackonexception (status, err); at                 Throwerr; -             } -             Catch(Exception ex) { -                 //transactional code threw unexpected exception-rollback - rollbackonexception (status, ex); -                 Throw NewUndeclaredthrowableexception (ex, "Transactioncallback threw undeclared checked exception"); in             } -              This. Transactionmanager.commit (status); to             returnresult; +         } -}

It can be inferred from the above code that the key code that actually executes the business method is: action.dointransaction (status);

Right, there is an entry transactioncallback<t>, look at the source of the interface:

1  Public Interface Transactioncallback<t> {25    T dointransaction (transactionstatus status); 6 7 }

This interface has only one dointransaction method, so it is very simple that we can put the business code in the Dointransaction by means of an anonymous inner class:

Examples are as follows:

1 PrivatePayorderdao Payorderdao; 2   3 protectedtransactiontemplate transactiontemplate; 4   5 /** 6 * Save Payment order7  */  8 protectedPayorder Savepayreq (FinalPayorder Payorder) {  9     Ten @Autowired One     Privatetransactiontemplate transactiontemplate; A    - @Autowired -     PrivatePayorderdao Payorderdao; the    -Payorder order = (Payorder) This. Transactiontemplate -. Execute (NewTransactioncallback () { - @Override +                  PublicObject dointransaction (transactionstatus status) { -                     //See if a payment order already exists and return the order primary key if it already exists +Payorder payordertemp =Payorderdao.findorder (String A . ValueOf (Payorder.getpayorderid ()));  at    -                     //transaction type (PayType) converted by payment channel type (PAYCHANNELTYPE) -                     if(Payorder.getpaychannelid (). Equalsignorecase (Pay_chnl_act_bal)) {//account balance Payment -Payorder.setpaytype ("3");  -}Else if(Payorder.getpaychannelid (). Equalsignorecase (Pay_chnl_fast_pay)) {//Unicom Express Payment -Payorder.setpaytype ("4");  in}Else{//Online Banking Gateway Payment -Payorder.setpaytype ("2");  to                     }   +    -                     //The new payment amount is the same as the original order amount, if the inconsistency is incorrect the                     if(Payordertemp = =NULL) {   *String orderId =Payorderdao.save (Payorder);  $ Payorder.setpayorderid (orderId); Panax Notoginseng                         returnPayorder;  -}Else {   the                         returnpayordertemp;  +                     }   A                 }   the             });  +     if("2". Equals (Order.getorderstate ())) {//2: Payment Success -         Throw Newepaymentbizexception (StatusCode.DQSystem.PAY_FAIL, $"The same order cannot be paid again");  $}Else if(Payorder.getpayamt (). Longvalue ()! =Order.getpayamt () - . Longvalue ()) {   -         Throw Newepaymentbizexception (StatusCode.DQSystem.PAY_FAIL, the"The transaction amount is inconsistent with the original order");  -}Else {  Wuyi         returnPayorder;  the     }   -    Wu}

Another way to manage spring transactions--transactiontemplate programming transaction management simple Getting Started