Why do you develop middleware when you are young? "You can choose your own way"

author ： Little brother Fu

Blog ：https://bugstack.cn

precipitation 、 Share 、 grow up , Let yourself and others have something to gain ！

One 、 Preface

young , Why middleware development ？

Five years ago , Xianghe Big factory The village , It's a good start . My brothers and I are ambitious , Go to the interview by bus , Who knows the job less than half a month , On average... Every day 1.3 I'm hanging in the Eight Legged essay to build a rocket , Within a year 6 A brother went to outsource .

The Buddha bless ！ The fortune teller said I was “CRUD To move the brick 996”, But I don't agree . I think it's going to be , yes 20K yes 40K, It's up to you .

You follow me for the shortest time , The foundation is the thinnest , How can I get there , Let you choose for yourself .

Okay , I wish you all the best , In the big factory , everything is going smoothly ！ Cheers, architects ！

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At the end of the day , Why do you want to open up CRUD Surface , Go deep into the core source code and learn some middleware development skills , I don't want to have a certain depth in learning technology stack , In order to avoid being cheated on the salary during the interview . It's like someone asking you ：

• Proxy for class 、 In what scenario are reflection calls used ？
• How do custom annotations get information together with facets ？
• What you need yml How configuration information is SpringBoot Load and initialize ？
• Bean How is it injected into Spring Containers , serviceable ？
• ORM How does the framework solve the problem of executing without writing an interface implementation class CRUD Operation of the ？
• What is the relationship between the disturbance function and the data hash in the database routing implementation ？
• Distributed task scheduling and zookeeper How does the configuration center interact ？
• How to intercept the run-time information of the program method ？

Sum up , And so on, these technical points may be many times what you learn can only be called Recite the answer 、 Record the results , Because there is no practical exercise, so later forget and also can't bear the interviewer's continuous questions .

that , In order to make all of them need to deepen their knowledge of technology stack , Practical experience in developing relevant skills , At the same time, we also let the small partners who are interested in middleware development with high salary , There is a tutorial to get started . I hereby prepare a column booklet 《SpringBoot Middleware design and development 》, Welcome aboard ！

Full volume 19 Chapters , Include 16 Design and development of middleware , Including test cases 30 A code base for readers to learn to use . The middleware scenarios implemented in the booklet cover ： Technical framework 、 Data services 、 Data components 、 Distributed technology 、 Service governance 、 Bytecode 、IDEA Seven aspects of plug-ins , Throughout the Internet system architecture commonly used in the core content . It's worth learning 、 Study 、 From practice to mastery .

Jian The author's level is limited , If the book contains something difficult to understand , It must be that the author lacks the necessary description and strict calibration in the process of writing , Thank you for your comments or questions , Welcome to interact with me more , Make progress and grow together .

Two 、 Middleware development technology

If you usually just do more business code development , Then, the technology of contact is generally in all kinds of components API On use , And the packaging of different interfaces . Middleware development involves the source code and principle of various frameworks , And the corresponding technology migration and reuse . So in our middleware design and Implementation , You'll learn the framework 、 data 、 government 、 Knowledge of distributed and bytecode technology stack , The whole system includes the following ：

chart 2-1

• Technical framework ： Include Spring、SpringBoot Configuration is loaded 、 Custom annotation 、 Scan the registration Bean etc. , as well as ORM Framework design principle and implementation . This part of technology is mainly to combine the middleware and framework , Develop corresponding components or package them for various kinds of SpringBoot Starter Ability to learn .
• Data services ：Mysql、Redis、Elasticsearch, It's all data services , It is usually necessary to develop various components to encapsulate the use of data services ,Mysql We know there are JDBC,Redis We know there are Jedis, but Elasticsearch Yes x-pack Do you understand .
• Data components ： This kind of component is developed to simplify the use of data services ,Mysql+JDBC+ORM, It is very convenient to use database services , that Elasticsearch Whether we can also do the corresponding component research and development , So that its queries can also be used like MyBatis The same ？ Second, the technical ability of folding needs to MyBatis etc. ORM The implementation principle of the framework is familiar with , At the same time, we need to understand JDBC The concept of .
• Distributed technology ：RPC frame 、 Registry Center 、 Distributed tasks , They are very important technologies in the existing Internet distributed architecture , And how to achieve a RPC frame , Technology is also the focus of R & D personnel , And how to use the registry 、 How to distribute distributed scheduling tasks , wait , The study of these technologies can help us have a deeper understanding of the use of existing frameworks .
• Service governance ： Fuse 、 Downgrade 、 Current limiting 、 Tangent 、 Black and white lists and non intrusive extensions to existing methods , Can be a service governance component , Originally, this kind of technology was integrated with business logic code in the early days , Later, it was gradually disassembled , Develop corresponding components . So we can learn , About the packaging of these components 、 How is integration done .
• Bytecode & plug-in unit ： In the operation and maintenance process of Internet system application , You'll be exposed to all kinds of monitoring systems , And many monitoring systems are non intrusive full link monitoring , So how is this achieved ？ In fact, they are based on bytecode instrumentation , Enhancements to the system approach , Collect the corresponding runtime information , Monitoring . And then to expansion JVMTI、IDEA Plug-in development , All for the sustainable delivery and launch of the whole R & D process, improving delivery quality and reducing human efficiency .

Sum up , These kinds of typical middleware run through the whole Internet system architecture , They will be explained in the following chapters , How they are designed and implemented , A little bit of middleware to take you out of the mystery , Let your technology stack knowledge also increase some in-depth and hands-on content .

3、 ... and 、 Middleware design and implementation list

Serial number	Icon	name	describe
1		Service governance , Unified white list control	Solve the risk of online verification , White list specific user opening verification
2		Service governance , Timeout fusing	Packaging timeout call , Reduce the cost of business system access
3		Service governance , Call current limiting	Wrapper interface calls current limiting , Reduce the cost of business system access
4		Service governance , Custom interception method	Do not destroy existing methods , Enhance method service capabilities
5		ORM Framework implementations	Study ORM Framework core design , Implement the simple version MyBatis
6		ORM Framework and Spring aggregate	be familiar with Bean scanning 、 agent 、 register 、 Management etc. , And right ORM Packaging
7		combination SpringBoot Development ORM Starter	ORM、Spring And SpringBoot combination , Automating initial configuration , Development Starter
8		ES-JDBC Query engine	understand Elasticsearch JDBC Source code implementation of component ,x-pack-jdbc
9		ES SpringBoot Starter Service Framework	Application ORM Technology migration , Development ES Class ORM frame , Solve the query mapping complexity , Do object-oriented development packaging
10		RPC Framework implementations	Study RPC Framework design and development , Understand the communication principle and implementation
11		Database routing component	Hash algorithm 、 Section treatment 、 Data source switching 、 Custom configuration combined with practice , Developing routing components
12		Redis Simplify the use of encapsulation	Handle Redis The second packaging of , Simplify to interface proxy mode , Reduce application costs , And make it easier to upgrade
13		Distributed task scheduling	In registration 、 Mission 、 Console , Develop distributed task scheduling under multi-party content composition
14		Non intrusion monitoring design ,ASM Bytecode stub	Learn about bytecode instrumentation , Study Javaagent Non intrusive monitoring mode of processing
15		Non intrusion monitoring design ,JVMTI Location code	understand JVMTI Technical ability , Development C++ dll Components , Enhance monitoring capability
16		IDEA Plug in is combined with bytecode stub	combination IDEA Plug in development and bytecode enhancement technology , Collect the execution information in the process of code development and operation , Analyze and improve delivery quality

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Pamphlet 16 A middleware implementation , Including test engineering, etc 30 Code base , Each chapter will correspond to the design and implementation of middleware , In order to facilitate readers to quickly and effectively learn the technical content in the booklet , Here is the content structure of the chapters in the booklet , Cover the following 5 Aspect content ：

1. Introduction , In technology 、 Experience 、 Growth and other aspects of the summary of the content , Help you broaden your knowledge and increase your growth experience .
2. Demand background , Describe the scenarios of this middleware 、 What needs are put forward to solve what pain points .
3. The project design , Pain points in the context of demand , Do middleware architecture design , Including design draft and implementation description .
4. Technical realization , It is mainly the implementation of the scheme design , This process will include the complete implementation of the source code and all the core code explanation . Ensure that you can complete the design and development of Middleware in the process of learning .
5. Test verification , Every middleware implementation has a corresponding test project , for example ：whitelist-spring-boot-starter And whitelist-spring-boot-starter-test. The expected verification of middleware is realized through test engineering , It can make it easier for you to understand the background of a requirement 、 Design 、 The process from implementation to delivery verification .
6. At the end of the paper , It's a summary of each article , It is also a helpful reminder for readers to study this article at the end of the article , I also hope that the information you learn is far more perfect than what you summarize from the perspective of the author .

Four 、 What will you learn ？

• Spring Loading of configuration files 、Bean scanning 、 Definition 、 Registration, etc.
• Spring Boot About Starter Common technical means and skills of development
• ORM、RPC、 Database routing 、 Service governance 、 System monitoring 、IDEA Middleware design in plug-ins and other scenarios
• Proxy for class 、 Reflection call 、 Section treatment 、 Bytecode stub 、 Perturbation function enhanced hashing and JVMTI And other core technologies
• 30 A code base allows you to design middleware 、 Realization 、 verification , Have a clear understanding of

5、 ... and 、 Appropriate crowd

• Have Java R & D personnel of programming foundation , Understand part of the framework source code , All kinds of technology components are often used
• We need to improve our core technical ability
• Interested in middleware development , But I don't know where to start
• Yes SpringBoot Development Starter Technical requirements of

6、 ... and 、 Data learning

1. 《SpringBoot Middleware design and development 》 Full access to columns and pamphlets undefined Good! , It's with your help 、 Support 、 recognition 、 Encouraging , What you want to see Middleware design and development I'm here to meet you ！ It's a growing stage for programmers to break through technical bottlenecks and improve technical cognition , Should understand and learn the content , come on. ！ Remember to have any problems with your column , Please contact this excellent man ： Little brother Fu , WeChat ：fustack
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3. You can join the middleware communication group , Add my wechat ：fustack remarks ： Middleware cluster