[learning notes] seckill - seckill project - (11) project summary

One 、 Second kill project summary

1.1 Project framework construction

• SpringBoot Environment building
• Integrate Thymeleaf,RespBean
• Mybatis

1.2 Distributed session

• The user login
  • Design database
    User table ： Account id, password , Encrypting salt, etc
  • Plaintext password twice MD5 encryption
    The first time is because of http Plaintext transmission requires encryption , The second is to prevent the database from being stolen
  • Parameter checking + Global exception handling
    Through the input parameters LoginVo annotations @validated, Then in the passed in parameter mobile and password Add comments to judge whether it is empty
    Global exception handling is to prompt the user for exceptions
• share Session
  • SpringSession
  • Redis

1.3 Function development

• List of goods
  To display product information , Need to encapsulate GoodsVo, To display product information , Including the price , stock , Second kill start and end time, etc
• Goods details
  Also need to GoodsDetailsVo
• seckill
  At the control level, first judge the inventory , stay redis Inventory reduction in advance , Then judge whether the order exists , Send a request To the message queue , Create order after
• Order details
  establish OrderVo

1.4 System pressure test

• JMeter
• Custom variables simulate multiple users
• Formal pressure measurement
  • List of goods
  • seckill

1.5 Page optimization

• Page caching +URL cache + Object caching
  1. The bottleneck of seckill lies in the database , So we need to add cache of various granularity , The biggest is page caching 、 The smallest is the object cache
  2. Page caching steps （ List of goods ）
     from redisService Take the cache from , If not in the cache, use thymeleaf Render the page manually , Then add the page to the cache , And return to the rendering page .
  3. URL cache （ Product details page ）
     It is basically the same as the page caching steps , But you need to add parameter goods when fetching cache and adding cache ID
  4. Object caching （User）
     The previous page cache and URL Caching is suitable for small changes , Cache time is relatively short . Object cache is a long-term cache . The first step is to fetch the cache , If the cache is not , Then go to the database to find , And add cache ; If there is no in the database , Throw an exception .
• Page static , Fore and aft end separation
  1. Static page is to use pure HTML page +Ajax request json Fill the page after data
  2. if A The page jumps to B You can judge the conditions before the page A Use... In the page ajax Request judgment before jumping
  3. If you don't need it, you can jump directly to B page , from B The page initiates itself ajax request
• Static resource optimization

1.6 Interface optimization

• Redis Reduce stock in advance , Reduce database access
• Memory tags , Reduce Redis visit
  When the system is initialized, load the commodity inventory to redis Mark in , There is no need to read from the database when judging inventory , Directly in redis Read from
• RabbitMQ Order asynchronously
  • SpringBoot Integrate RabbitMQ
  • Switch

1.7 Security optimization

• Seckill interface address hidden
  When the front page is not started, the seckill button is set to unavailable , But there may be users through the front end js The code finds the seckill address , Visit directly before the second kill , Secsha interface is hidden for users to pass js The obtained seckill address cannot let him perform seckill operation
  Pass before the second kill starts Controller Medium /path The class under the path randomly generates a path, And then with the user ID、 goods ID Deposit together redis. When executing the second kill, start from redis To take path To verify , Then do a second kill
• Arithmetic captcha
• Interface anti brush
  When the user accesses the interface , Write the number of accesses to the cache , And set the validity period . Record the number of visits in one minute , If you go beyond the limit , Then conduct current limiting operation . If there is no overrun , Then the cache disappears , Write the cache again on the next access

1.8 Seckill process

1. Log in to the product list page , Static resources are cached into redis
2. Click to enter the product details page , Static resources are cached into redis, adopt Ajax Get dynamic information such as verification code
3. Click second kill , Compare the verification code result with the product ID Pass to the back end , If correct . Dynamic generation UUID, Plus users ID And commodities ID Deposit in redis, And put the path path To the front end . Front end according to path Address call seckill service
4. The server gets the requested path Parameters , Query if there is a cache
5. exist , And redis There is also inventory information in , It's in redis Pre reduce inventory in , See whether the order is generated , If not , Send the request to the message queue
6. Get messages from the message queue ： Access to goods ID, user ID, To place an order
7. Order operation ： Reduce inventory , Generate order
8. The front end polls the order generation results and whether the second kill is successful

Two 、 Key and difficult points of the project

The implementation of secsha interface with high concurrency 、 And security optimization

3、 ... and 、 Project recommend

After finishing secsha or grain mall , What do you usually choose if you want to do a personalized project ？ You can design according to the highlights and difficulties .

3.1 Project highlight design

• Code quality
  For example, do unit tests , Test code coverage
• Project online
  Deploy to the cloud
• Manufacturing accident scene , Pressure measurement site
  For example, adding cache , How many times the performance

3.2 Difficult design of the project

• Create memory leaks OOM Of Bug, Then make troubleshooting 、 The process of repair
• Create concurrency problems , Such as deadlock 、HashMap Cause concurrency , Switch to ConcurrentHashMap、 Atomic classes 、volatile
• Sudden increase of traffic , Flood storage and discharge