Programmer Group

  0x01: byte stream Byte stream base class 1. InputStream InputStream: the base class of byte input stream. The abstract class is a superclass representing all classes of byte input stream. Common methods: // Reads the next byte of data from the input stream abstract int read() // A certain number of bytes are read from the input st ...

1. Scenario Display Regular expressions and corresponding functions are the same in oracle and mysql. Introduction to regular expression symbols: '^' Matches the start position of the input string, used in a square bracket expression, where it indicates that the character set is not accepted. '$' Matches the end of the input string. If set Re ...

1. Define your own database and data table 2. Access the defined data table through JDBC and insert 2 records. Requirements: 1. Submit SQL statements defined in database and data table; 2. Submit program implementation process; 3. Submit program running results. This is a small class assignment assigned by my teacher. What is JDBC JDBC(Jav ...

preface In C language, file is an important concept in programming. The operating system manages data in the unit of files. Although there may not be many places to use files in the future, files are still an indispensable part of C language. Well, no more nonsense. Let's get straight to the point. 1, What is a file Concept: files on dis ...

Technical introduction Date processing in java has always been a problem. There is no good way to handle it, so there is a third-party framework, such as joda. This article mainly explains the java date processing in detail. Joda can be used in 1.8. Time concept First, let's introduce some basic concepts, in which GMT and UTC can be expressed a ...

021. Delete the penultimate node of the linked list Title: Given a linked list, delete the penultimate node of the linked list, and return the head node of the linked list. Example: Input: head = [1,2,3,4,5], n = 2 Output: [1,2,3,5] Idea: Fast and slow pointers: the slow pointer is the head node, the difference between the f ...

1. What is the Linux three swordsman First of all, we want to know what the Linux three swordsmen are? The first tool is grep, which performs pattern pattern in each file or matching line, that is, searches the content according to the regular expression and prints it out The second tool is awk, which is abbreviated by three authors (aho, Kern ...

Original text: https://www.cnblogs.com/JanSN/p/12540247.html Because Python is a dynamic language and the Concept of Duck Typing is all over it, the Concept does not take type constraints as the carrier, but uses a Concept called protocol. In Python   I need to call one of your methods, and you happen to have this method.For example, in st ...

Today, I'm going to relearn enumeration types in Java. Why study again now? Because when I first started learning Java, I didn't pay much attention to enumeration. After work, I basically didn't use enumeration. As a result, I don't quite understand the data type of enumeration. Sometimes when I see the enumeration types and related operations ...

0. Architecture diagram 1. Network and system settings 1.1 /etc/profile agent sudo vi /etc/profile Comment out the following agent configuration source /etc/profile 1.2 wget agent sudo vi /etc/wgetrc 1.3 clearing environment variables env | grep -i proxy unset HTTPS_PROXY unset HTTP_PROXY unset FTP_PROXY unset https_prox ...