2022/07/29 jisoft Java Foundation (14) exception handling
1, What is exception handling Exception handling is also called exception handling. There are two purposes to deal with exceptions in the program, one is to find the exceptions in the program, and the other is to operate the exceptions relatively or notify the programmer to modify them. Using the try catch statement can accomplish these two pur ...
Posted by bothwell on Sat, 06 Aug 2022 21:26:11 +0300
NIO Selector execution process
1, What is Seletor?
The literal meaning of selector is not easy to understand. Seletor is a listener that can listen to events in the Channel. Channels can be registered in the seletor. When these registered channels have events, the seletor's select method will return these events to the thread for processing.
2, The difference bet ...
Posted by Fari on Tue, 02 Aug 2022 21:10:27 +0300
Kotlin - delay initialization and sealing classes
1, lateinit delay initialization keyword
Many syntax features in Kotlin, such as variable immutability, variable non nullability, and so on, are designed to ensure program safety as much as possible. For example, there are many global variable instances in your class. In order to ensure that they can meet Kotlin's null pointer check sta ...
Posted by Cut on Sun, 31 Jul 2022 22:28:16 +0300
Java from getting started to giving up 06 (what is object-oriented?)
What is object-oriented?
Process oriented
The process oriented method of solving problems is to follow the steps we have analyzed, step by step, follow the principle of top-down and gradual refinement, and focus on the process and steps of solving problems.
object-oriented
Java Language is an object-oriented programming language, and obj ...
Posted by the_ut_tick on Sat, 30 Jul 2022 22:17:10 +0300
Automatic recognition of nucleic acid detection time by software using OpenCV
Question introduction
In the program engineering training course, a problem occurred:
Mobile phone screenshot nucleic acid detection report, using OpenCV software to automatically identify whether the time for nucleic acid detection is within 72 hours.
I. Preparations
Software needed to accomplish this task:
- Python3.x
- OpenCV-Py ...
Posted by fitzromeo on Sat, 02 Jul 2022 22:04:45 +0300
Write, append, read, and copy of golang files: examples of using bufio packages
Write, append, read and copy operations of golang files
There is an OpenFile function under the os package of the Go language. Its prototype is as follows:
func OpenFile(name string, flag int, perm FileMode) (file *File, err error)
Where name is the file name of the file. If you are not running under the current path, you need to add the spe ...
Posted by teddmcload on Thu, 30 Jun 2022 16:56:27 +0300
IV. source code analysis of nacos Registry -- health detection
I. core principle flow chart
II. The client monitors the server
2.1 implement udp listening
The constructor of PushReceiver will trigger the initialization of listener
public PushReceiver(HostReactor hostReactor) {
try {
this.hostReactor = hostReactor;
this.udpSocket = new DatagramSocket();
thi ...
Posted by spitfire_esquive on Thu, 30 Jun 2022 16:41:17 +0300
C++ copy constructor
copy constructor
We often use a variable to initialize a variable of the same type, so there should be similar operations for custom types, so how to use an existing object to create another same object when creating an object?
Constructor: There is only a single parameter, which is a reference to an object of this class type (usually cons ...
Posted by mad81 on Wed, 25 May 2022 10:40:27 +0300
Techniques for improving the performance of Java string encoding and decoding
Introduction: common string codes include LATIN1, UTF-8, UTF-16 and GB18030. They have their own characteristics, and the conversion between them is complex. This article will introduce the skills to improve the performance of Java string encoding and decoding.
Author Wen Shaojin (high speed railway)
Source: Alibaba developer official account
...
Posted by phil88 on Tue, 24 May 2022 14:50:50 +0300
T, E, K, V in generics, remember?
preface Benefits of generics Wildcards in generics
Commonly used T, E, K, V,? ？ Unbounded wildcards Upper bound wildcard <? extends E> Wildcard lower bound? super E> ？ Difference between and T Class < T > and "class <? > difference Summary
preface
Java generics is a new feature introduced in JDK 5. Ge ...
Posted by jb60606 on Mon, 23 May 2022 23:59:38 +0300