Shulou(Shulou.com)06/01 Report--

Senior Software engineer

The following interview questions are language-independent, applicable to all programming languages, and are more biased towards design.

Design a classification function

This function is used for administrative division, commodity classification, etc., such as China-> Guangdong-Shenzhen.

Request:

Infinite pole classification, unlimited depth

Fast retrieval, cannot use recursion

Can only be implemented using one database table

You can generate a tree directory

Commodities and designs belonging to xxx

A commodity has many attributes, such as size and color, which have fixed values, while other attributes, such as weight, volume need to fill in specific values, and there are corresponding units.

Request:

Commodity classification (implemented in the previous question)

Commodity attributes, there are multiple attributes, and the number is uncertain, so it needs to be designed to be added infinitely.

The commodity attribute can be selected by drop-down, or you can fill in the specific value.

Question:

Product search how to solve download, including product name, attribute value, description search

How to design and download the inventory of goods

Classification search, how to list all subcategories and all classifications under subcategories (infinite depth)

Functional requirements for user registration

Scenario simulation: when users open an account, they often fill in some information and then leave. There are several situations.

User abandons registration

Network connection failed

Error in submission

Other links attracted users to click on.

And so on.

Demand:

When you are asked to record the user to fill in the information and click to register again (a few days / months later), the user does not have to re-fill in all the information, just complete the unfinished part.

Important information such as mobile phones, e-mails, instant messaging numbers, etc., need to be recorded in the database and have been revisited by the company.

After successful registration, users should delete mobile phones, e-mails, instant messages, etc., which were previously left in the database.

May I ask how to achieve it? How to keep the data? download

Transaction related

Briefly what is transaction processing?

How to maintain data consistency when database transactions and locks (table / row-level locks) cannot be used? How to solve the database concurrent operation?

How to prevent multiple users from reading the same data record?

How to prevent multiple users from updating the same piece of data

Simulation problem 1

For example, there is an e-commerce site where 100 users place orders every hour, and the company needs 10 customer service to process users' orders.

Question:

What's wrong with checking orders when 10 employees enter the admin background?

How to prevent an order from being seen by more than one person? download

If two employees and colleagues see the same order, how to prevent employees from repeatedly approving the same order? download

If order X is first clicked by employee A, this means that employee An is busy with other things, and the X point will be suspended all the time. How to redistribute the order?

Development framework

A brief introduction to the principle and implementation of MVC

How to implement URL routing

How to implement class and method access control download

Could you tell me how to download the following code?

Do it in the language you know best.

{% highlight java%}

DB db = new DB () db.select (new field ("name", "age"...)) .from ("user") .where (new And ("xxx=xx", "xxx=xxx")) .limit (10) .offset (10) .orderby ("id", DESC)

{% endhighlight%}

Process and multithreading

What is blocking and what is non-blocking?

What is synchronous and what is asynchronous?

Under what circumstances do you use thread locks?

What is the difference between processes and threads?

What are the types of inter-process communication, what are the thread communications, and what are their respective advantages?

Message queue

What are the bottlenecks in the message?

Serialization

What is serialization?

What are the downloads of common serialization methods

CDN application

How does CDN cache work?

What content can be cached by CDN?

90% of the content on the home page of the website is static, but how to solve the problem that the user login status and message status are dynamic?

Is it possible to cache JSON? download

The relationship between browser cache and CDN cache, how to achieve user browser and CDN cache at the same time?

Object-oriented questions?

Write a summation program

S = new Sum (); s.add (10) .add (5) .add (6) s.add (10) .add (5) .add (6) .add (3) can be written indefinitely obj = new Object () obj.a () obj.b () obj.c (). Obj.z () obj.a () .b () .c ()... Z ()

Similar to the above

This is a simple OOP interview question, in many years of interview experience, found that many people do not know how to achieve the above questions

Restfull examination questions

Restfull is a RPC system based on HTTP protocol, there are no security considerations for public services, and most of the invocation methods are ajax, so the public system is open.

If it is a private service, you need to consider the security issue. The questions are as follows:

CQRS problem

What is CQRS?

CQRS can be handled in those places

Please add HTTP Auth to Restful

How to add HTTP Certification to Restful

What are the ways to download to add http certification

Are users and passwords secure?

Encrypt Restful using SSL

What is the difference between the purchased certificate and the self-generated certificate

How and where to configure SSL

What should be paid attention to when accessing the Restful of SSL

Database Application Database Segmentation

What is smooth segmentation and what is vertical segmentation?

Sub-table, sub-library need to be the main items

Sub-table, how to solve the Kuaku query after sub-database

Sub-table, how to create index after sub-database

Database replication problem

What are the types of database replication? download

A brief description of master-slave replication, master-master replication, circular replication

What are the considerations in software development when choosing master-slave replication?

How does the master apply

Elastic Design of Software Elastic Design Compiler language

Background simulation: an e-commerce platform has been developed, compiled and packaged, launched, and operated. Due to the rapidly changing market, the original discount system design can no longer meet the current demand, if not modified, it will bring economy to the company at any time. Now you need to modify the program logic again, but here comes the problem. At present, promotion and promotion activities are being carried out, and the large number of visits to the system can not interrupt the existing services, even 30 will bring irreparable losses to the company.

My question:

How to solve the following problems at the beginning of the design of this system?

How to design a flexible discount system to download

How to adapt the internal running logic of the compiled language without restarting

Problem extension: this problem can be extended to Apple IOS. For example, it takes at least half a month to release app to Apple appstore. There may be many variables in half a month. It is likely that the application will be approved, and the program is no longer suitable for the current situation.

High availability design

What is high availability?

What is the dual hot standby? what are the defects of the dual hot backup?

What is double work?

Please briefly describe what factors should be considered to achieve high software availability.

Disaster preparedness in software design

Please briefly design a remote disaster preparedness system

How to design disaster preparedness system in two computer rooms

How to design disaster preparedness system in three computer rooms

What influencing factors need to be considered in cross-border situations

Development of software disaster preparedness

How to realize disaster recovery in Database

How to realize disaster recovery by caching

How to realize disaster recovery by Application Server

How to download disaster recovery by Web Server

How to plan tasks and periodically run programs for disaster preparedness?

How to realize disaster recovery by message queue

How to realize that double active software can only run one or alternately at the same time?

Software deployment issu

How to realize the automatic deployment of software, and what are the key points to realize the automatic deployment?

How to handle configuration files

How to exclude files that are unnecessary or unwanted to deploy

How to implement incremental deployment

How to achieve differential deployment

How to deploy large files, such as video, etc. Problem: there is a file with 500m, the content is modified at any time, and it will be added from time to time, how to achieve differential deployment, instead of releasing a 500m file again.

How to deploy compiled software

How to back up

How to deploy windows programs to download

How to quickly pull back, switch the point in time or the specified version.

GIT/SVN is not allowed to be used for automatic deployment. Automation is not required to be completed within 30 seconds.

The implementation principle of Software Development Framework plug-in

The plug-in consists of several parts

How to install, uninstall, enable and disable plug-ins?

Install, uninstall, enable, disable how to achieve non-downtime, do not shut down the service?

Dictate how to design a MVC framework download

How to implement URL routing

How to realize the controller

How to implement the view

How to implement the model

Dictate how to design a SOA framework

How many parts is the framework divided into?

What protocol is used to communicate with the framework?

How do you implement it if you use the binary protocol for performance?

How to resolve concurrency conflicts?

How to support transactions?

How do you integrate or communicate with message queues?

Dictate the design of a distributed planning task system

Background: scheduled tasks are programs that run periodically or regularly. In order to solve the problem of single point of failure and load balancing, a single node is not allowed in a distributed system.

Design requirements: high availability, load balancing, scale-out

How to deal with conflicts caused by running at the same time?

How to queue up to run?

How is the task persisted?

If one node goes down, how can the other node take over the unfinished tasks?

How to scale out?

Expansion, contraction, maintenance, if you can achieve non-downtime, do not affect the business?

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