Java basics --- reflection mechanism, java basics ---1. Is java a Dynamic Language?
Generally speaking, dynamic language means that the program structure or variable type can be changed while the program is running. From this point of view, JAVA and C ++ are not dynamic languages.
But JAVA has a very prominent Dynamic correlation mechanism: reflection. Through reflection, Java can load, explore, and use cla
Python BASICS (6): List and metadata, and python Basics
I. List
The list is a container where a group of data can be placed, and each element in the list has a location index. Each element in the list can be changed. operations on the list will affect the original list. The definition of the List is defined by "[]". elements are separated by commas (,), for example:
a = [12,'hello',15.5,True]
A list is defi
Python BASICS (4): Conditions and loops, python Basics
In actual development, if you want to implement certain functions or requirements, some logic is involved, complicated or simple. How can you implement the python syntax? This involves conditions and loops. Obviously, most languages have conditional and cyclic syntaxes, and python syntaxes are similar to them. It is easy to learn, and students with basi
Python BASICS (10)-numbers, python basics-Numbers
The topic of this article is numbers in Python. Describes each numeric type in detail, the various operators they apply, and the built-in functions used to process numbers. At the end of the article, I briefly introduced several modules used to process numbers in the standard library.
URL: http://www.cnblogs.com/archimedes/p/python-number.html.Numeric type
N
Java programming basics-Fibonacci series and programming Basics
Problem description: A frog can jump to level 1 or Level 2 at a time. Find the total number of hops that the frog jumps to an n-level step.
Thought: possible situations: (1) n = 1, one method; (2) n = 2, two methods; (3) for level n, only jump from level n-1 or level N-2, so draw the conclusion:
| 1, (n = 1)
F (n) = | 2, (n = 2)| F (n-1) +
Java concurrency basics and java concurrency Basics
Concurrency is the ability to run multiple programs in parallel or run multiple parts of a program in parallel. If a time-consuming task in a program can be run asynchronously or in parallel, the throughput and interactivity of the entire program will be greatly improved. Modern PCs have multiple CPUs or one CPU has multiple cores. Whether multi-core capab
Java basics --- XML parsing (1), basics --- xmlXML is a scalable Markup Language
In the XML file, because more information is described, you should use the definition name of the element installed in the program to remove the corresponding content after obtaining an xml file, such an operation is called XML parsing.
In XML parsing, W3C defines the parsing methods of the SAX and DOM. program operations of th
Learning mysql syntax-basics (1), mysql syntax-Basics
PrefaceMysqlMysql syntax-This article uses Navicat Premium (Database Management Tool) to connect to mysql data.This article mainly consists of two parts:1. Create a user, create a database, assign permissions to the user, and delete user permissions.Ii. Common Data Types in MYSQLIii. Table-create a table, primary key, and foreign keyIv. Three paradigms
[Java tutorial 00] Computer basics, java Computer BasicsPreface
I think my friends here must want to learn JAVA or want to enter the IT industry. Considering that people may have different foundations, some people may still use new computers to make their learning smoother. Before learning a new computer language, I need to popularize some basic computer knowledge.Basic computer knowledge
Computer: an electronic Computer, commonly known as a Compute
Full Java basics and full Java Basics
This is a full set of basic java knowledge that I have prepared in my previous lectures. It can also be used by beginners for intermediate programmers. I have made it a chm document type. You can download the notes in a comprehensive and systematic manner, it can be up to 90% of the learning materials on the market. I hate the casually written information and the peopl
Full Java basics and full Java Basics
This is a full set of basic java knowledge that I have prepared in my previous lectures. It can also be used by beginners for intermediate programmers. I have made it a chm document type. You can download the notes in a comprehensive and systematic manner, it can be up to 90% of the learning materials on the market. I hate the casually written information and the peopl
Jacva BASICS (II) and jacva Basics
Data Type Variable Operator
1. Data Type
Basic Type: Class 8
Integer: byte short int long
Floating Point (decimal): double float
Character: char
Boolean: boolean
Reference Type: String type
2. Variables
Essence: a space in the memory used to store various types of data.
Three elements: data type variable name variable value
Syntax for declaring variables:
I: name of the da
Concurrent Programming (1) ---- Concurrent Programming basics, ---- programming Basics
Multithreading is a basic knowledge that programmers must master. However, due to the encapsulation of various frameworks, we seldom access multithreading. Once a problem occurs in the project, you cannot start. Multi-threading not only helps you better handle project problems, but also helps you understand some framework
Java basics-GUI programming (2), java basics gui Programming
I. event listening Mechanism
-- Event Source: the graphical components in the awt or swing package, that is, the components in which the event occurs.
-- Event: An operation performed by the Event user on the component.
-- Listener: Listener is responsible for event processing.
Ii. classes in the java. awt. event package
WindowEvent // window even
Java basics-I/O (3) and java basics I/O
1. Pipeline Flow
Demo: PipedInputStream and PipedOutputStream
Note: Pipeline streams are not recommended in one thread because the data written to the output stream is saved to an array of 1024 bytes in the input stream, if the written content exceeds the size of this array and is not read by the input stream, the thread where the output stream is located will wait. I
Java basics-JSP (2), java basics jsp
1. JSP implicit object Overview
To simplify the compilation of jsp expressions and script snippet code, JSP provides a total of nine pre-defined variables, also known as implicit objects or built-in objects.
The Servlet Source code generated by jsp contains the following declaration:
Public void _ jspService (final javax. servlet. http. httpServletRequest request, final
I. The CLR's FCL, CTS, and CLS1. The CLR is the common Language runtime, the common language runtime for the Microsoft. NET Framework.2. CTS is the common type system (common type systems), which is a formal specification developed by Microsoft to describe the definition and behavior of types, so that code written in one programming language can communicate with another programming language.The CTS stipulates that a type can consist of 0 or more members.
Fields (field)
Methods (me
Python basics-process and thread, python basics thread
I. Concepts of processes and threads
First, the concept of "multi-task" is introduced: multi-task processing means that users can run multiple applications at the same time. Each application is called a task. Linux and windows are multi-task operating systems, which are much more powerful than single-task systems.
For example, if you are using a browser
Python basics 2. python Basics
Iii. Analysis of variables, objects and values
1. If you don't remember it, it will be finished.
1.1 remember: all data is an object
1.2 remember: all variables are references to data objects.
1.3 analysis: reference count sys. getrefcount in python
2. variable naming rules
2.1 remember what you can do. It must start with a letter.
2.2 remember what you cannot do. You
SQL basics (1), SQL BASICS (
I. mysql management commands
/Applications/XAMPP/xamppfiles/bin/mysql-uroot
1. display all databases
Show databases;
2. Enter the mysql database
USE mysql;
3. display the currently displayed Library
Select database ();
4. display the names of all tables in the current database
Show tables;
5. query all records of the SQL table name
SELECT * FROM SQL;
6. log out of the mysql serv
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