标签：http协议 name down oid byte address 虚拟 substring 客户端
web服务器也称为www(world wide web)服务器，主要功能是提供网上信息浏览服务。web服务器是可以向发出请求的浏览器提供文档的程序。
一般可分成如下4个步骤：连接过程、请求过程、应答过程以及关闭连接。下面对这4个步骤作一简单的介绍。
Web服务器上述4个步骤环环相扣、紧密相联，逻辑性比较强，可以支持多个进程、多个线程以及多个进程与多个线程相混合的技术。
服务器一般可以用c语言、Java、Python来写主体框架。以下用Java写在windows10的服务器。
服务器的不同写法从根本上都是遵循同一套网络协议的，在网络上传递的数据是完全一致的，对于客户端而言，服务器的具体写法并不影响消息的传递。
web服务器最基本功能：
在设计服务器功能时，可以分为三块，用三个类来写：
主类HttpServer
import java.net.Socket; import java.net.ServerSocket; import java.net.InetAddress; import java.io.InputStream; import java.io.OutputStream; import java.io.IOException; import java.io.File; public class HttpServer { public static final String WEB_ROOT = System.getProperty("user.dir") + File.separator + "webroot"; private static final String SHUTDOWN_COMMAND = "/SHUTDOWN"; private boolean shutdown = false; public static void main(String[] args) { HttpServer server = new HttpServer(); server.await(); } public void await() { ServerSocket serverSocket = null; int port = 8080; try { serverSocket = new ServerSocket(port, 1, InetAddress.getByName("127.0.0.1")); } catch (IOException e) { e.printStackTrace(); System.exit(1); } while (!shutdown) { Socket socket = null; InputStream input = null; OutputStream output = null; try { socket = serverSocket.accept(); input = socket.getInputStream(); output = socket.getOutputStream(); Request request = new Request(input); request.parse(); Response response = new Response(output); response.setRequest(request); response.sendStaticResource(); socket.close(); shutdown = request.getUri().equals(SHUTDOWN_COMMAND); } catch (Exception e) { e.printStackTrace(); continue; } } } }
请求类Request
import java.io.InputStream; import java.io.IOException; public class Request { private InputStream input; private String uri; public Request(InputStream input) { this.input = input; } public void parse() { StringBuffer request = new StringBuffer(2048); int i; byte[] buffer = new byte[2048]; try { i = input.read(buffer); } catch (IOException e) { e.printStackTrace(); i = -1; } for (int j = 0; j < i; j++) { request.append((char) buffer[j]); } System.out.print(request.toString()); uri = parseUri(request.toString()); } private String parseUri(String requestString) { int index1, index2; index1 = requestString.indexOf(‘ ‘); if (index1 != -1) { index2 = requestString.indexOf(‘ ‘, index1 + 1); if (index2 > index1) return requestString.substring(index1 + 1, index2); } return null; } public String getUri() { return uri; } }
响应类Response
import java.io.OutputStream; import java.io.IOException; import java.io.FileInputStream; import java.io.File; public class Response { private static final int BUFFER_SIZE = 1024; Request request; OutputStream output; public Response(OutputStream output) { this.output = output; } public void setRequest(Request request) { this.request = request; } public void sendStaticResource() throws IOException { byte[] bytes = new byte[BUFFER_SIZE]; FileInputStream fis = null; try { File file = new File(HttpServer.WEB_ROOT, request.getUri()); if (file.exists()) { fis = new FileInputStream(file); int ch = fis.read(bytes, 0, BUFFER_SIZE); while (ch != -1) { output.write(bytes, 0, ch); ch = fis.read(bytes, 0, BUFFER_SIZE); } } else { String errorMessage = "HTTP/1.1 404 File Not Found\r\n" + "Content-Type: text/html\r\n" + "Content-Length: 23\r\n" + "\r\n" + "<h1>File Not Found</h1>"; output.write(errorMessage.getBytes()); } } catch (Exception e) { System.out.println(e.toString()); } finally { if (fis != null) fis.close(); } } }
标签：http协议 name down oid byte address 虚拟 substring 客户端
原文地址：https://www.cnblogs.com/heibaimao123/p/9535446.html
