Programming VIP

Redis client summary redis is a distributed cache database with C/S architecture. It has its own command-line client and corresponding Java or other language clients. redis can be read and written through some API s in these clients. preparation Step 1: create a project. Create a maven parent project, such as 03 redis, and create two sub p ...

I Connection pool 1. Introduction Mybatis uses its own connection pool technology, which can be found in mybatis config XML As shown in the figure: 2. Classification of mybaits connection pool UNPOOLED does not use the data source of the connection pool POOLED uses the data source of the connection pool JNDI database connection pool implem ...

1 Introduction 1.1 background In our current project architecture, the Web server (Tomcat) and database are basically deployed independently and monopolize the server resources. With the growth of the number of users, concurrent reading and writing to the database will increase the pressure on database access and lead to performance degradati ...

expiration mechanism As long as it is a cache, there must be an expiration mechanism. guava cache expiration is divided into the following three types:expireAfterAccess: if the data is not accessed (read or write) within the specified time, it is expired data. When there is no data or the expired data is read, only one thread is allowed to upda ...

After several school recruitment interviews, I found that http cache has been used as an interview question. When I first met this question, I was confused, so I summarized the following contents In any front-end project, it is common to access the server to obtain data. However, if the same data is repeatedly requested more than once, the red ...

Install redis standalone Step 1: install the GCC environment required for the C language yum install -y gcc-c++ yum install -y wget Step 2: Download and unzip the Redis source code package cd /root/redis wget http://download.redis.io/releases/redis-5.0.5.tar.gz tar -zxf redis-5.0.5.tar.gz Step 3: compile the Redis source code, enter the ...

1. What is flink? Flink is a distributed open source computing framework for data stream processing and batch data processing, which supports both stream and batch applications. Because the SLAs (Service Level Agreement) provided by streaming and batching are completely different, streaming generally requires support for low latency, Exact ...

Common cache algorithms:First in first out (FIFO) queue: first in first out. The data that enters first is eliminated first. Disadvantages: ignore the data access frequency and access times.Least recently used (LRU) : least recently used algorithm, that is, if the data has been accessed recently, the probability of being accessed in the future ...

brief introduction Today, we mainly learn about global unified exception handling step try catch is often used in Web applications, which will lead to the feeling of disordered code structure and is not conducive to debugging code. It will be a good thing if all exceptions can be unified into one module. Then @ ControllerAdvice and @ Excepti ...

Implementation of limited time rush purchase Use Redis to record the time of second kill goods and reject requests that have expired! Put the second kill goods into Redis and set the expiration time Use String type to set a certain expiration time in the form of kill + commodity id as key and commodity id as value (180 seconds here) Introdu ...