Programmer Group

PS: This article is detailed, so it is long. Reading time: 30m~1h. Please read it carefully. I hope you can have a clear understanding of unified exception handling in an hour. 1. Background In the process of software development, it is inevitable to deal with all kinds of exceptions. For myself, at least more than half of the time is dealing ...

1. Problem Description: Concurrent lrucache is used as the JVM cache pool object public class UserManager { private ConcurrentLruCache<UserCacheKey, UserInfo> cache = new ConcurrentLruCache<UserCacheKey, UserInfo>(100, new Function<UserCacheKey, UserInfo>() { @Override public UserInfo apply(UserCacheK ...

1, Review Following the last "dynamic header easyExcel import and export"( https://blog.csdn.net/qq_37337660/article/details/114680512)"， And the last dynamic header import( https://blog.csdn.net/qq_37337660/article/details/110288393 )”After that. We have a third wave easyExcel Torture, this time export complex Excel, by the w ...

3. Construction of Maven project 3.1 contents of Maven project The structure of the project is as follows: See the following figure for details: 3.2 commands for manually building projects mvn compile #compile mvn clean #eliminate mvn test #test mvn package #pack mvn install #Install to local warehouse Just be familiar ...

Summary of JUC multithreaded programming JUC: use of java.util.concurrent multithreading Toolkit Test demo:https://gitee.com/aqq/mytest.git 1. Daemon thread There are two kinds of threads in java: user thread and daemon thread Only if the user thread in the current JVM does not end, the daemon thread will work. Only when the last user thre ...

1: Introduction to thread pool Using thread pool, you can reuse threads and control the total number of threads. If the thread pool is not used, a new thread should be opened for each task. The overhead of repeatedly creating threads is large, and too many threads will occupy too much memory. This is too expensive. We want to have a fixed num ...

Algorithm efficiency In use, the algorithm efficiency is divided into two types: one is time efficiency (time complexity) and the other is space efficiency (space complexity). Time complexity refers to the speed at which the program runs. Spatial complexity refers to the additional space required by an algorithm. Time complexity What is ...

maven dependency <!--redis--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> <!--<version>2.1.4.RELEASE</version>--> </dependency> <dependency> ...

The emergence of Coroutines has subverted the programming style of Java for many years. If you are the author of a third-party library, you may want to use Coroutines and Flow to make your Java callback based library more Kotlin and collaborative. On the other hand, if you are an API consumer, you may prefer to access the Coroutines style API t ...

Use scenarios and versions Use scenarios Export information to excelEnter information from excel table into website database (exercise upload.) excel version Version 03 xls rows Max 65535 rowsVersion 07 xlsx has no limit on the number of rows One serious problem with POI is that it consumes a lot of memory EasyExcel is an open source exce ...