Analysis of the transaction problem of chained method call

Recently, I have done a distributed project , Of course, there is no design for distributed transaction processing , A logic line is too long , Methods and methods , So the problem of affairs between them is exposed
I'm dead , Code directly


 

@Service
public class TransactionalServiceImpl implements TransactionalService {

    @Autowired
    private CgpMngUserbraService cgpMngUserbraService;

    @Transactional
    @Override
    public void method() {
        CgpMngUserbra cgpMngUserbra = cgpMngUserbraService.selectUserBraRules(0, 0);
        if (null == cgpMngUserbra) {
            cgpMngUserbraService.insertUserBraRules(0, 0, "method");
        }
        method2();
    }

//    @Transactional// The transaction will not take effect here , The reason can be found in the last blog 
//     Portal ---> https://blog.csdn.net/fanxb92/article/details/81296005
    public void method2() {
        CgpMngUserbra cgpMngUserbra = cgpMngUserbraService.selectUserBraRules(0, 0);
        if (null == cgpMngUserbra) {
            cgpMngUserbraService.insertUserBraRules(0, 0, "method2");
        }
        TransactionalServiceImpl transactionalService = (TransactionalServiceImpl) AopContext.currentProxy();
        transactionalService.method3();
    }

    @Transactional
//    @Transactional(propagation = Propagation.REQUIRES_NEW)
//    @Transactional(propagation = Propagation.NESTED)
    public void method3() {
        CgpMngUserbra cgpMngUserbra = cgpMngUserbraService.selectUserBraRules(0, 0);
        if (null == cgpMngUserbra) {
            cgpMngUserbraService.insertUserBraRules(0, 0, "method3");
        }
    }
}

First, let's introduce the test logic ：

1、method,method2,method3 The three methods will save the same data in a table , And chain call .

2、method2 Adding transactions does not take effect ,method2 Medium transaction and method Consistent in , Refer to the blog link in the code .

3、 Here is the test cascading transaction ,method3 The above three transaction processing methods

• The first one is @Transactional,method3 The transaction in is consistent with the previous （method In the transaction generated by annotation on method ）, All done , A piece of data in the database (createdBy = 'method'). It must be all implemented , Break in the middle ,method For inserting into the database , Because the method is not over , not commit.
• The second kind @Transactional(propagation = Propagation.REQUIRES_NEW),method3 Opened a new transaction , Will suspend the existing transaction ,

Again , After all the methods are executed, two pieces of data in the database , The screenshot of the database record is as follows ：

so , yes method The storage time of medium data is before , analysis ===>
！！！！！！！！！ It's very important here , It may not be concise and accurate , Experience carefully ！！！！！！！！！！！！！！！！！！

method In the implementation of insert( The first piece of data will be inserted createdBy = 'method'), When the method is not executed, it is not commit, There is no insert record in the database , But in the cache .

method2 Methods are nested in method In the method , In the same business ,method2 The record will be queried in the method , So no more data will be inserted .

method3 Methods are nested in method2 In the method , Opened a new transaction , Will not find method Data in method transactions , So it will execute insert( Insert the second data createdBy = 'method3').

 Here are the details ！！！>>>>>>method3 Method to start a new transaction , After the method is executed, it will be submitted ,
 Can be found in method3 It's over, but method Where it's not over, break , You will see that the database has records (createdBy = 'method3').
 Let go of the breakpoint , All done , The database has two records , As shown in the screenshot above .
 It can be seen that it is possible to cascade and start new transactions , But you must call external methods to take effect , Or use AopContext.currentProxy().

• The third kind of @Transactional(propagation = Propagation.NESTED)

Throw an exception JpaDialect does not support savepoints - check your JPA provider's capabilities
public JpaTransactionManager() {setNestedTransactionAllowed(true);}

Only later did I know Hibernate Nor does it support Nested Transaction, The test doesn't work , Only use jdbc Business , Use JdbcTemplate.

ok , Let's talk so much first . Thank you for reading .