Programmer Think

1. Generic overview 1.1 understanding generics Generic, that is, parameterized types. The essence of generics is to parameterize types Parameterized type, that is, the type is parameterized from the original specific type, which is similar to the variable parameters in the method. At this time, the type is also defined as a parameter f ...

Before, some readers asked me if I have any useful BI (Business Intelligence) tools? BI tool is simply a data visualization tool. Today, I recommend an open-source data visualization tool DataEase, which is implemented based on SpringBoot and integrated with Apache Doris + Kettle. It can support second level query of large amount of data. I hop ...

Introduction: Hello, iron juice, a few days ago, it was snowing heavily in many cities ~ (Xiaobian in Hunan really didn't get too excited to see such heavy snow after a few years) I don't know if the lucky youyoumeng had fun snow? The snowball fight and the snowman wo are all played~ 😜😜 Skiing didn't come true, so this issue of Xiaobian wan ...

 pip install django Create project Enter the d:\projects directory and execute Django admin startproject bysms Create the following directory structure: bysms / project root         manage.py is a tool script used for project management The bysms / directory is a python package. It contains importan ...

1, Introduction to ThreadLocal ThreadLocal is called thread variable, which means that the variable filled in ThreadLocal belongs to the current thread and is isolated from other threads, that is, the variable is unique to the current thread. ThreadLocal creates a copy of the variable in each thread, so each thread can access its own int ...

regular expression catalogue regular expression 1, What is a regular expression? What is a regular expression? Purpose of regular expression: Important statement How to know regular expressions Java support for regular expressions Usage example of Pattern class 1. Sharing mode 2. Independent mode Method usage example of String cla ...

background Yesterday, Xiao Feng received an interview call from a company. One of the interview questions was a little interesting. I'll share it with you here. The interview question is how to delete the specified element in ArrayList. At first glance, it sounds like a simple question, but if you don't actually step on the pit, you can easi ...

Although you have built an index on this column and the query criteria are also index columns, the final execution plan does not take its index. Here are some key points causing this problem. Column to column comparison In a table, two columns (ID and c_id) have separate indexes. The following query criteria will not go through the index ...

Recently, when writing an ID generator, we need to compare the speed difference between UUID and the popular NanoID. Of course, we also need to test the ID generator created according to the rules. Such code belongs to the most basic API. Even if the speed is reduced by a few nanoseconds, it can add up considerably. The key is, how can I evalu ...

preface If is often used in the development process else... Judge, throw exceptions, branch handling, etc. These if else... Flooding in the code seriously affects the beauty of the code. At this time, we can use the Function interface of Java 8 to eliminate if else.... if (...){ throw new RuntimeException("Something's wrong")； } if (. ...