Apache HTTPCORE technical principle detailed explanation and examples

Detailed explanation and examples of Apache HTTPCORE technical principles Apache HTTPCORE is an open source Java library used to build a client and server application based on the HTTP protocol.It is the basic framework of Apache HTTPClient, which provides core components that process HTTP requests, responses and various functions related to HTTP.This article will introduce the technical principles of Apache HTTPCORE in detail and provide some Java code examples. 1. Overview of Apache httpcore Apache httpcore mainly includes the following two core components: HTTPCODEC and HTTPCORE-NIO. 1. HttpCodec HTTPCODEC is one of the core components of HTTPCORE, which is used to handle HTTP requests and responses.The main task is to convert the request and response message into byte flow in order to transmit it on the network.HTTPCODEC provides several different codecs to process different HTTP message formats, such as HTTP/1.1 and HTTP/2.Using HTTPCODEC, you can easily encode the HTTP message into byte array, or decoding the byte array to HTTP message. 2. HttpCore-NIO HTTPCORE-NIO is another core component of HTTPCORE, which provides NIO (NON-Blocking I/O, non-blocking I/O) mode to achieve efficient IO operations.Different from traditional blocking I/O, using NIO can achieve high concurrency and high -performance network communication.HTTPCORE-NIO uses the Java selector to build the buffer, process the inlet HTTP request and send HTTP response in non-blocking.At the same time, it also provides asynchronous processing HTTP requests and response capabilities, so that multiple HTTP request/response can not block the main thread.This makes HTTPCORE-NIO apply to server-side applications that need to process a large number of concurrent connections. Second, Apache httpcore's workflow The workflow of Apache HTTPCORE will be introduced in detail below. 1. Server workflow -Colon the HTTPSERVER object and specify the host and port to be bound. -Colon the HTTPPROCESSOR object and set the required protocol interceptor (such as a request to parse the interceptor and respond to generating interceptors). -Colon the httprequestHandlerMapper object to map URI to the corresponding request processor. -Colon the HTTPSERVICE object and set HTTPPROCESSOR and HTTPREQUEQUESTHANDLERMAPPER to HTTPSERVICE. -Colon the NHTTPCONNECTIONFACTORY object to create a connection based on the HTTP protocol. -Colon the IOREACTOR object and register HTTPSERVER into the iOREACTOR. -Beoppy IOREACTOR.Once the IOREACTOR starts, it will start to listen to the connection request. -The specific processing process is as follows: a. When a new connection request arrives, iOREACTOR will create a new I/O thread to process this request. b. Read the bytes from the connection I/O thread, and use HTTPCODEC to decode the byte to be httprequest.It then passed HttpRequest to HTTPSERVICE for processing. c. Httpservice handed HTTPREQUEST to HttprequestHandlerMapper to determine the request processor. d. HttpRequestHandler handles httprequest and generates the corresponding httpresponse. E. I/O thread uses HTTPCODEC to encode HTTPRESPONSE into bytes and write it back to the client. f. Close the connection and end the entire processing process. 2. Client workflow -Colon the ConnectionConfig object and set the configuration parameters of the connection. -Colon the IOREACTOR object. -Colon the AsyncclientBuilder object, set up I/Oreactor and ConnectionConfig, and build an Asyncclient object. -Colon HTTPHOST and HTTPREQUEST objects. -Call the Execute method of Asyncclient and pass it into HTTPHOST and HTTPREQUEST objects. -ASYNCCLIENT uses HTTPCODEC to encode HTTPREQUEST as bytes and send it to the server. -ASYNCCLIENT receives HTTPRESPONSE from the server and uses HTTPCODEC to decoding it as an HTTPRESPONSE object. -Chiside the response result according to the httpresponse object. 3. Apache httpcore example code The following is a simple Apache Httpcore example code, which demonstrates communication based on HTTPCORE-NIO and clients. 1. Server code // Create httpserver HttpServer server = ServerBootstrap.bootstrap() .setListenerPort(8080) .setServerInfo("HttpCore Server") .setConnectionReuseStrategy(NoConnectionReuseStrategy.INSTANCE) .registerHandler("/hello", (request, response, context) -> { StringEntity entity = new StringEntity("Hello, World!", ContentType.create("text/plain", "UTF-8")); response.setEntity(entity); }) .create(); // Start the server server.start(); 2. Client code // Create iOREACTOR IOReactor ioreactor = IOReactorBuilder.create().build(); // Create asyncclient try (CloseableHttpAsyncClient client = HttpAsyncClients.custom() .setIOReactor(ioreactor) .build()) { // Start asyncclient client.start(); // Create httphost and httprequest HttpHost host = new HttpHost("localhost", 8080, "http"); HttpRequest request = RequestBuilder.get().setUri("/hello").build(); // Execute the request Future<HttpResponse> future = client.execute(host, request, null); // Get the response HttpResponse response = future.get(); // Print results System.out.println(EntityUtils.toString(response.getEntity())); } This is a simple server -side and client communication example based on HTTPCORE.Through HTTPCORE, we can easily build applications based on the HTTP protocol and achieve efficient and reliable network communication. In summary, this article details the technical principles of Apache HTTPCORE, and provides a server-side and client communication example based on HTTPCORE-NIO.It is hoped that through the introduction of this article, it can deepen the understanding of Apache HTTPCORE, and can better apply it to build a high -performance HTTP application.