"Zhongfu Information"
—Java Summer Internship (Jinan)
Dialogue
The interview lasted about thirty minutes. The detection of one's own knowledge, the understanding of knowledge is very helpful! ! !
one side
Face : First, let me introduce myself.
Me: Hello, interviewer, my name is ***, I major in software engineering at Liaoning University, and I am currently a junior. (I used to sleep every day thinking about how to introduce myself, but I forgot when I was interviewing...)
Face : Tell us about your project.
Me: I faltered and explained the reasons for the long delay, but did not get to the point.
This project is a B2C business-to-customer e-commerce project, which integrates the previously learned technology stack.
Do I need to be more specific about this project?
Face : No, let’s talk about the process of Spring Security
Me: SpringSecurity is similar to the general security framework shrio, mainly for authentication and authorization. It needs to inject a bean encryption and salt, (that class has not been spelled out yet, alas). Then implement a class, inherit a class, complete the authentication, and finally authorize the role. (Without serious recitation, there is indeed a problem with language expression)
Side : Are you familiar with zookeeper?
Me: (In retrospect, I said a lot of nonsense at the beginning, and I should cut directly to the topic) zookeeper can be summarized as a file system + monitoring notification mechanism. The file system is similar to the UNIX file system. There are four types of nodes: persistent, persistent order, Temporary type, temporary sequence, the maximum capacity is 1MB. The monitoring notification mechanism is that the server registers in zk, the client accesses it, and the client registers a watcher in the registry. Whenever the server modifies, deletes or increases or decreases the number of new nodes, it will notify the client. The watcher can only be used once. Prevent frequent operations and increase server pressure. Zookeeper has the ZAB protocol. When the server cluster is down or restarted, it will enter the crash recovery state, elect a leader, and the followers will replicate the data. When more than half of the recovery, it will enter the message broadcasting state and start processing client access.
Face : Do you know redis?
Me: (I think about it now, I should talk about NoSQL, in-memory database, key-value!!! When I am here, I am a little confused...) This is asking me about the basic data types of redis, which is very Basic, string, map, list, set, zset, (speaking fluently)
Face : Then have you learned about redis data storage?
Me: redis stores data in memory, so it is fast.
Father : What if the power goes out?
Me: redis can synchronize data to disk.
Face : Do you know how to do it?
Me: It seems that you can set the node to store to disk. (...I found it, I'm talking nonsense here...)
Face : Do you know the isolation level of the database?
Me: There are four isolation levels, (then I can't remember what I said...) Let the interviewer remind me, but I don't remember it. Finally, I said that I couldn't remember the four English letters. The interviewer asked me to speak Chinese, but I didn't remember it either. (—_—``` said that sql server and oracle are one level, which can prevent dirty reading, and mysql is one level higher, which can prevent dirty reading and repeated reading.
Family : Are you familiar with map?
Me: Mentioned iterators, collection, map is hashmap, hashtable
Face : talk about the difference between hashmap and hashtable
Me: One thread safe and one unsafe.
Face : Which thread safe?
Me: hashtable thread safety
Face : Do you know why?
Me: Add the sychronized keyword modification, the same as string. (I said that I didn't study the map carefully, so the interview hall suggested me to learn basic multi-threading, ... In fact, for the se part, I just waited for the last question on the back. The interviewer suggested that there must be his reason, take the time to do it. Do it, the basics are good, and there is no trouble in learning.)
Face : Do you know the seven-layer protocol of computer network?
Me: Computer Networking is a course offered this semester. I thought it was a summer interview, so I wrote it on my resume in advance. Physical layer, data link layer, network layer, application layer.
(This answer is very messy, and some can’t remember it clearly.)
Face : Which layer is TCP at?
Me: Network layer (pure nonsense!)
Face : Are you familiar with linux? Say a few common linux commands
Me: (I think it’s too simple to say common commands, I said a lot of my Alibaba Cloud server was attacked, and how to solve the problem buried a hole for myself, but I didn’t answer the question)
**面：查看内存占用的命令**
Me: It suddenly dawned on me that if I had known this order at the time, it would have been easier. Said the top command to view the process. . . Because the memory usage will not, ahahaha I'm really witty.
Face: three characteristics of object-oriented
Facet: Permission Access Modifiers
Face : What is the difference between spring and springboot? bean life cycle
Me: I said roughly, if I want to expand, the interviewer may have other things to do, so I didn’t expand.