concept pm3

database.Hibernate's core componentsHibernate Comprehensive Solution Architecture:Hibernate component hierarchy:These components are divided into 5 layers in the order in which they are used, and the upper layer can be invoked and used on the lower layer.1) Hibernate configuration file: Used primarily to configure database connection parameters. such as database drivers, URLs, user names, passwords, and so on.It has two forms: Hibernate.properties and Hibernate.cfg.xml. The configuration conten

= = = ' Buffer '? c8> Buffer.from (value.data): value;}); // output: console.log (copy);Buffer MergeGrammar:Buffer.concat (list[, Totallength])var buffer1 = Buffer.from (' rookie tutorial '); var buffer2 = Buffer.from ((' www.runoob.com ')); var buffer3 = Buffer.concat ([Buffer1,buffer2]); Console.log ("Buffer3 content:" + buffer3.tostring ());Buffer comparisonGrammar:Buf.compare (Otherbuffer); var buffer1 = Buffer.from (' ABC ' var result = Buffer1.compare (buffer2); if (Result + "

into the system. This account and user is a concept, through the establishment of different attributes of the user, on the one hand, can be reasonable use and control of system resources, on the other hand, can also help users organize files to provide security protection for user files. Each user uses a unique username and user password to enter the system and its home directory only if the user name and password are entered correctly when logging

#include 1. An existing process creates a new process by calling the function fork (), which is a copy of the calling process (the parent process).pid_t Fork ();The fork () function returns two times, returns the process ID of the child process in the parent process, and returns 0 in the child process.2. In the subprocess we execute the input command line by calling the function EXECLP () to load the new program into the new process.3. In the parent process, we call the function waitpid () to wa

packages that store software dependencies. easy for developers to maintain software package dependencies. Add the new packages in the development process to this list to avoid missing packages when the setup.py installation is dependent. Make it easy for readers to identify which Python packages the project uses. README: project documentation, functions as follows: software positioning, the basic functions of the software. How to run your code: Installation environment, star

string is divided according to the parameter separator to the maximum number of int, if an empty string ("") is used as separator, then each character in the Stringobject is divided. Separator can be either a string or a regular expression. String: The array is created by splitting the string stringobject into substrings at the boundary specified by separator. The string in the returned array does not include the separator itself. Regular Expressions: The returned array includes st

1. Callback functionIn fact, the callback function of PHP is exactly the same as the function of the callback function of C, Java and so on, all of which are in the process of executing the main thread and suddenly jump to execute the set callback function;After the callback function is executed, go back to the main thread to process the next processInstead of using the function name as a function parameter in PHP, like C and Java, the callback function is executed in PHP using the corresponding

sharing of the same application, but also realize the security sharing of public resources of different applications.3, Semaphore: It allows multiple threads to access the same resource at the same time, but needs to limit the maximum number of threads accessing this resource at the same time ;4. Events: It is also convenient to implement a priority comparison of multiple threads by keeping the threads synchronized in a notification operation .Iii. why multi-threaded programming is requiredThe

virtual hardware to running an application on an operating system that uses a specific logical resource. This provides ISSS flexibility while providing the simplicity of the PAAs, and is much more than running 12-factor applications. separation of concerns for development and operations : Provides a separation of build and deployment, and thus decoupling the application from the infrastructure. Agile Application creation and deployment : Container mirroring is more lightweight and effic

CSS is the abbreviation of the English cascading style Sheets , CSS is currently the latest version of CSS3, is able to truly achieve Web page performance and content separation of a style design language. Compared to the performance of traditional HTML, CSS can control the placement of objects in the Web page with pixel-level precision, support almost all font size styles, have the ability to edit Web objects and model styles, and be able to conduct preliminary interaction design, is currently

One, the communication between components The scope of the component instance is orphaned, which means that the data of the parent component cannot and should not be referenced directly within the child component's template. However, there is a need for communication between parent and child components, which the child component needs to communicate to the parent component to pass data to the child component. in Vue.js, the parent-child component's relationship can be summarized as props do

', port)) Gevent_server.listen () while True: CLI, addr = gevent_server.accept () Gevent.spawn (HANDLE_REQUEST,CLI) def handle_request (conn): try: while True: data = CONN.RECV (1024x768) print ("recv:", data) conn.send (data) if not data: Conn.shutdown (socket.) SHUT_WR) except Exception as ex: print (ex) finally: conn.close () if __name__ = = "__main__": Server (8001)There are two t

inherited structure, the order of execution is to first execute the static block of code from the topmost class to the lowest level, then execute the construction method from the top to the bottom. You cannot access a non-static member variable in a static method, you can access a static member variable in a static method, or you can access a static member variable in a non-static method. The this pointer cannot be used in static, which refers to the current instance.This article is from the "L

the substance.3, GeneratorThe generator function implements true asynchronous control that switches the execution environment and passes variables between execution environments to implement collaborative function threads.The well-known co modules, combined with promise and generator, enable synchronous coding of asynchronous processes.4. Async functionThe ES2017 standard introduces an async function that makes asynchronous operations easier. Is the syntactic sugar of the Generator function.The

Closures: The main role is to encapsulate variables, convergence permissions. Prevent the variable from being contaminated. For example, the jquery framework uses a large number of closures. Why is it?Ask a question? How does the framework avoid conflicts between the variables you declare and the variables that it comes from????? Obviously, need to close the bag!!! Valid only in the scope that you define.The concept and usage of closure in JS

The most classic introduction to the concept and usage of the ASP.Abstract Factory mode provides the client with an interface that enables the client to create objects in multiple product families without having to specify a specific type. This article still takes the example of the fast food restaurant that followed.Now, fast food restaurants often good, gradually grow, in order to fit different local people's eating habits, created two series (equiv

To figure out these three methods, you first need to understand the concept of capturing groups in a Java regular expression. The capturing group is also the sub-pattern of the pattern in parentheses to "()". The main reason to use capturing groups is to find out what you care more about in a match.Capturing groups can be numbered by calculating their opening brackets from left to right. For example, in an expression "(x) (y\\w*) (z)", there are three

a "read-modify-write" sequence of operations, and the resulting state depends on the previous state.In concurrent programming, incorrect results due to improper execution order is a very important case, the race condition (Race Condition).Race conditionA race condition occurs when the correctness of a calculation depends on the alternating execution timing of multiple threads. The most common race condition is the "check after execution (check-then-act)" operation, which determines the next act

be taken out, but directly execute.So, what is the sequence of these two functions executing? No hurry, let's debug: var getUserInfo = function () { console.log(‘aaa‘); $.getJSON("http://www.easy-mock.com/mock/5a09868228b23066479b8379/ajaxData/getUserInfo", function () { console.log(‘bbb‘); return data; }); } var data = getUserInfo(); console.log(data); console.log(‘ccc‘); renderUserInfo(data); The output of sequenti

of the window to interact with the external user (another system) of the perspective of the interface to the user to commit to the system to provide what services, stand in the system itself, the interface of the system must implement what services, An interface is the highest-level abstract type in a system. Interface interaction can improve the coupling system between two systems A through system B interaction, refers to system a access to system B, the reference variable is declared as the i