Analyze and study the technical principles of the HTTP Client framework in the Java library

HTTP Client is a framework for sending HTTP requests and receiving HTTP responses in the Java class library.Based on Java's network communication technology, it provides a simple and flexible way to process HTTP communication. The technical principles of the http client framework involve the following key points: 1. URL and URI parsing: HTTP Client first needs to analyze the URL or URI provided by the user to obtain information such as host address, port slogan, path and other information.This information is the basis for sending HTTP requests. 2. Establish connection: HTTP Client uses Java's socket or HTTPClient class to establish TCP connection with the target server.Before the connection is established, it will find the target server through the host address and port number and perform DNS parsing. 3. Send request: Once you establish a connection with the target server, the HTTP Client will build an HTTP request.This includes the selection request method (GET, Post, etc.), setting request header (Content-Type, Cookie, etc.), and setting request body (form data or JSON data, etc.). 4. Receive response: HTTP Client sends a request to the server and wait for the server's response.Once the response is received, it will analyze the response status code, response head and response body.This information is very important for further processing response. 5. Processing response: HTTP Client can handle the response as needed.This includes the processing of response status codes (200, 404, etc.), parsing response (JSON, HTML, etc.), processing response head (cookie, etc.). HTTP Client's function extension also includes connection pool management, redirect processing, cookies management, and certification processing.It provides various configuration options and plug -in mechanisms, which can be customized according to actual needs. Below is an example code that uses Java's HTTP Client framework to send GET requests: import java.net.URI; import java.net.http.HttpClient; import java.net.http.HttpRequest; import java.net.http.HttpResponse; public class HttpClientExample { public static void main(String[] args) throws Exception { // Create HTTPCLIENT object HttpClient httpClient = HttpClient.newHttpClient(); // Create the httprequest object, specify the request URL HttpRequest httpRequest = HttpRequest.newBuilder() .uri(new URI("http://example.com")) .build(); // Send a GET request and get a response HttpResponse<String> response = httpClient.send(httpRequest, HttpResponse.BodyHandlers.ofString()); // Analysis response int statusCode = response.statusCode(); String responseBody = response.body(); // Processing response data System.out.println("Status code: " + statusCode); System.out.println("Response body: " + responseBody); } } In the above example, we use the HTTPClient class that comes with Java 11 to send GET requests and get response.By specifying the request URL, you can get the response status code and response after sending the request.This example shows the basic usage of the HTTP Client framework. In short, the HTTP Client framework plays an important role in the Java class library, providing simple and powerful HTTP communication capabilities.By understanding its technical principles in depth, we can better use this framework for development and tuning HTTP communication.