In-depth understanding of the implementation principles of the Swagger's Swagger's Swagger Note Framework

In -depth understanding of the implementation principle of the Swagger annotation framework in the Java library Swagger is a popular API development tool that helps developers to automatically generate and maintain API documents.The Swagger annotation framework is used in the Java library, which can describe the details of the API and various metadata by adding annotations, thereby simplifying the writing of API documents.This article will study the implementation principles of the Swagger annotation framework in the Java class library, and how to use it to generate API documents. Introduction to the Swagger annotation framework The Swagger annotation framework is an open source framework used in the Java class library. It describes the details and metadata of the API by adding annotations.These annotations can be applied to class, methods and fields to define the requests and response structures, parameters, paths and other related metadata of API.By using the Swagger annotation framework, we can automatically generate API documents from the code, including the data structure, path information and other metadata of requests and response. 2. The implementation principle of the Swagger annotation framework The implementation principle of the Swagger annotation framework can be divided into two main steps: scanning and analyzing annotations, and generating API documents. 1. Scan and analytical annotation Use the Swagger annotation framework in the Java library, first of all, scanning, analysis, and processing of annotations need to be scanned.The annotation processing is implemented through the reflection mechanism, which can obtain the annotation information on the class, methods and fields.The Swagger annotation framework is defined by defining some predefined annotations, such as@API,@Apiopration,@APIPARAM, etc. to indicate all aspects of the API. When we run the application, the Swagger annotation framework scan the annotated class, methods and fields, and analyze the metadata of these annotations.By analyzing these annotations, the Swagger annotation framework can obtain information such as the path, HTTP method, request and response structure, parameter such as HTTP methods, requests and response structures, and parameters.This information will be used to generate API documents. 2. Generate API documentation After scanning and parsing annotations, the Swagger annotation framework will use metadata in these annotations to generate API documents.API documents can include data structure, path information, parameter description of requests and response. The Swagger annotation framework usually generates an API document called the OpenAPI specification (also known as the Swagger specification).OpenAPI specification is a specification for describing API. It is a JSON format that can be used to generate common API document formats, such as Swagger UI or Redoc.The Swagger annotation framework will convert the metadata obtained by the annotation analysis into the format of the OpenAPI specification and generate the corresponding JSON document. 3. Use the Swagger annotation framework to generate API documents The following is an example of generating API documents using the Swagger annotation framework: @RestController @API (tags = "User Management") public class UserController { @APIPERATION (VALUE = "Get User List", notes = "Getting all user information") @GetMapping("/users") public List<User> getUsers() { // Get the implementation of the user list } @APIPERATION (VALUE = "Creating User", Notes = "Create a new user based on the transmitted user information") @PostMapping("/users") public User createUser(@RequestBody User user) { // Create user realization } } In the above example, we use@API,@APIPERATION annotation to define the metadata of the API, including API's labels, paths, HTTP methods, request parameters, requests and response data structures. By running the application, the Swagger annotation framework will scan and analyze these annotations and generate the corresponding API documentation.We can export the generated API document as a JSON file specified in OpenAPI, and then present it with tools such as Swagger UI or Redoc to present it as an API document that is easy to read. in conclusion By using the Swagger annotation framework, we can easily generate API documents for the Java class library.In terms of implementation, the Swagger annotation framework obtains the metadata of the API through scanning and parsing annotations, and then generates API documents.We can flexibly use the Swagger annotation framework to define and generate API documents according to the needs of the project, and improve the efficiency and reliability of API development. I hope that this article can help you understand the implementation principles of the Swagger annotation framework in the Java class library and successfully apply it in actual projects.If necessary, please refer to the official Swagger documentation and related tutorials to obtain more detailed information.