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
Python BASICS (2) -- functions, python basics -- Functions
Return Value:
All python functions have return values, but no return in the function body. The default return value is None,
Function parameters:
1. Common Parameters
In strict order, the actual parameters are assigned to the formal parameters, which correspond to each other.
Example:
def send(xxx,z,content): print(xxx,z,content)send("yy","dd",'
Python basics 1 and python Basics
Start python
Summary:
1. Introduction to python
Ii. Installation
3. The first python Program
Iv. Variable and character encoding
V. user input
Vi. Data Types
7. All objects
8. Data Operations
9. if else process judgment
10. while Loop
11. for Loop
12. break and continue
1. Introduction to python
Python introduction:
Python is the famous Guido van rosum (Guid
SpringMVC basics- ing problem, springmvc basics ing
I. SpringMVC uses RequestMapping to solve the ing problem.
2. Before learning RequestMapping, Let's first look at a picture.
This figure shows the request URL, request Method, request header, and request body contained when an http request is sent. The figure is clearly marked.
Iii. RequestMapping
1. The translation is request ing. In my opinion, the ing
JQuery BASICS (2) $ and jQuery basics in jquery
In jQuery, $ is the most commonly used symbol, which provides a variety of functions. This includes selecting one or more elements on the page, prefix of functional functions, perfection of windows. onload, and creation of DOM nodes. This document describes how to use jQuery. As the foundation
1. Selector
In css, selector is used to select a class (Category se
Jquery basics and jquery Basics
The first is that js loads the jquery library and must be written. The second is js that implements this function,
Function: click this button.
$ (Document). ready (function () {}); after the page is loaded.
$ ("Button"). click (function () {}); after the html page element of the button is clicked.
$ ("P"). hide () ;}); select this element of the html page element
Automated Testing basics-Selenium iframe problem locating, basics-seleniumSometimes we find a phenomenon on the way to positioning. The elements are there, but we cannot determine the location. At this time, we need the particularity of the specific webpage. This section describes how to handle iframe. I. Differences between frame and iframe: The functions of Frame and Iframe are basically the same, but Ifr
Python BASICS (13th) and python Basics
The re module contains regular expressions. This chapter introduces the main features and regular expressions of the re module.
What is a regular expression?
A regular expression is a pattern that can match a text clip. The simplest regular expression is a normal string that can match itself. In other words, the regular expression 'python' can match the string 'pytho
for(inti=0;i) {System.out.println (Thread.CurrentThread (). GetName ()); Random ran=NewRandom (); intA1=ran.nextint (1000); Try{thread.sleep (A1); } Catch(interruptedexception e) {//TODO Auto-generated catch blockE.printstacktrace (); } } }}Importcom.hanqi.test.Test03; Public classTest04 { Public Static voidMain (string[] args) {//multithreading for starting interface mode//cannot be started directlyTest03 t3 =NewTest03 (); //you need to construct thread to give him an instanc
(savedinstancestate); Setcontentview (R.layout.activity_main); //instantiation asynctask Asynctasktest test = new asynctasktest (); //start background thread test.execute (); //main thread perform task: Output Hello,world in log LOG.D ( "mainactivity" , "Hello, World" ); }}The output in the log after execution is:The first thing to do is onpreexecute, which is responsible for initializing the parameters and executing them in the UI thread, and then outputting the "Hello, World" output
not be able to respond to screen rotation. In this case, you have to correlate two directions that need to change and allow the user to switch between them until they begin to apply the main task. Start the main task, and then start responding to the device's movement. (WTF, this translation can not understand)
2.3.3 to communicate with layouts (using layout to communicate)The layout is not just a UI element in the interface, but through the layout, you can tell the user what information i
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