Distributed transaction framework LCN usage, principle and source code reading

Official website: https://www.codingapi.com/docs/home/

principle:

Come to the official website
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use:

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A eureka.
One TM and two RMs are order service and payment service respectively.
For detailed configuration, please visit the official website.

Order Service Controller:

    @PostMapping("/add-order")
    @Transactional(rollbackFor = Exception.class)
    @LcnTransaction
    public String add(@RequestBody TblOrder bean){
    
    

        JSONObject date = new JSONObject();
        date.put("payName",bean.getOrderName()+"pay");

        restTemplate.postForEntity("http://lcn-pay/add-pay",date,String.class);
        int i = 1/0;
        tblOrderDao.insert(bean);
        return "新增订单成功";
    }

Payment Service Controller:

    @PostMapping("/add-pay")
    @Transactional(rollbackFor = Exception.class)
    @LcnTransaction
    public String addPay(@RequestBody TblPay bean){
    
    
        tblPayDao.insert(bean);
//        int i = 1/0;
        return "新增支付成功";

    }

Just add @LcnTransaction

source code

1 entry:

Use the aop aspect class to intercept
TransactionAspect
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to obtain transaction messages:

Execution process:
determine whether there is a transaction context,
get the parent context if it exists

, create it if not,
and determine whether it is the transaction initiator
Put the context information in the cache,
click in and it will be a Map<String, Object> singlePropCache
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What is the general framework of startxx
Most of them will have
endXX
clearXX
cleanXX
destoryXX
Pull down the code:
find the destruction method
After execution, delete the context information in finally

and get the context information, set a bunch of parameters, blah blah, enter the key point :
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DTXServiceExecutor # transactionRunning

Obtain transaction propagation status

Start transaction operation
pre pre-execution
Transaction initiator initializes transaction group
Transaction participants do not execute anything

Business execution
is to execute the content of the method modified by @LcnTransaction annotation
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Execution completed successfully:

transaction initiator:
set the state to 1

transaction participant:
join the transaction group

Execution failed:
transaction initiator:
set the status to 0

transaction participant:
delete transaction information

Execution completed:
notify TM
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to click inside:

2 How does LCN obtain the operation database connection?

DataSourceAspect
intercepts when acquiring database connections:
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perform proxy, and package database connections of different types of transactions by yourself. Take

LCN as an example:
return your own data and connect proxy class:

do some own processing . The general process is

almost like this .
Let’s take a look at the TCC mode again.
If you are interested, you can discuss it together.