AXL FTP Server framework principle and its application in the Java class library

AXL FTP Server framework principle and its application in the Java class library Overview: AXL FTP Server is a Java -based open source FTP server framework that provides a lightweight and customized way to build and expand its FTP server.This article will introduce the framework principle of the AXL FTP Server, and provide some examples of applying and using AXL FTP Server in the Java class library. 1. The principle of framework: 1. Basic component of Axl FTP Server: AXL FTP Server consists of the following basic components: 1.1 FTP Server: Responsible for receiving FTP requests from the client and sending them to the corresponding processor for processing. 1.2 FTP Request Handler: Process FTP request and generate corresponding response data. 1.3 FTP Data Connection: The establishment and closing of FTP data transmission connection, and related operations of data transmission, such as uploading and downloading files. 1.4 FTP User Manager: Manage FTP users' certification and permissions control. 1.5 FTP File System: Define the file system structure and file operation method on the FTP server. 2. Working process: The workflow of AXL FTP Server is as follows: 2.1 Server start: Start the server by creating a FTP Server example, and specify the configuration parameters of the server, such as listening to ports and maximum number of connections. 2.2 Surveillance client connection: The server starts to listen to the client connection on the specified port.Once there is a client connection request to arrive, the server will receive connection and distribute it to the corresponding processor. 2.3 Processing FTP request: The FTP request processor calls different processing methods to process the request based on the receiving request types, such as login, listing file directory, upload files, etc., respectively.The processor will call FTP User Manager to verify the user's identity and perform permissions. 2.4 Processing data connection: For requests that need to be transmitted (such as uploading or downloading files), the server will create a FTP Data Connection and entrust the request data transmission operation to the data connection. 2.5 Response processing results: The FTP request processor package the processing results into response data and return to the client through the establishment control connection. 3. Support function: AXL FTP Server provides rich functions and extensions, allowing users to customize and expand according to their own needs.Some commonly used functions include: 3.1 User certification and permissions: Implement user certification and permissions control through FTP User Manager. 3.2 File upload and download: Support file upload and download operation. 3.3 File Directory Operation: Support the creation, deletion, rename and enumeration of the file directory. 3.4 File permissions management: Support file reading, writing, and execution permissions management. 3.5 Transfer mode selection: Support two data transmission modes: active mode and passive mode. 3.6 SSL/TLS encryption transmission: Support transmission data through SSL/TLS encryption. 2. Application in the Java library: It is very simple to use AXL FTP Server in the Java library. Below is a basic example of use: import org.apache.ftpserver.FtpServer; import org.apache.ftpserver.FtpServerFactory; import org.apache.ftpserver.usermanager.PropertiesUserManagerFactory; public class FtpServerExample { public static void main(String[] args) throws Exception { // Create FTP server factory FtpServerFactory serverFactory = new FtpServerFactory(); // Create a user manager factory PropertiesUserManagerFactory userManagerFactory = new PropertiesUserManagerFactory(); UserManagerFactory.setFile (new file ("users.properties"); // Set user attribute files // Set user manager serverFactory.setUserManager(userManagerFactory.createUserManager()); // Create FTP server instance FtpServer server = serverFactory.createServer(); // Start the server server.start(); // The server has started System.out.println ("FTP server has started"); } } The above example demonstrates how to create a simple FTP server with AXL FTP Server.First, use the `FTPSERVERFACTORY` to create an FTP server factory instance, and then use the` PropertiesuserManagerFactory` to create a user manager factory instance and set the user attribute file.Next, set the user manager to the server factory, and use the `CreateServer ()` method to create an FTP server instance.Finally, call the `Start ()" method to start the server. This is just a basic example. Axl FTP Server also provides rich configuration options and extensions, which can be customized and expanded as needed.You can get more detailed information and use examples by reading the official document. Summarize: This article introduces the principle of the Axl FTP Server framework and the application in the Java class library.AXL FTP Server provides a convenient and customized way to build and expand its FTP server.Through flexible configuration options and extensions, users can customize their FTP server according to their needs.Through a simple example code, we show how to use AXL FTP Server to create a basic FTP server.I hope this article will help you understand the principle of the AXL FTP Server framework and the application in the Java library.