我的第一个 web server 程序
参考书《How Tomcat Works》这本书非常好，我觉得翻译也不错。
根据第二章的例子，我写了我的第一个 web server 程序
HttpServer.java
package ex01.xiejiaohui;import java.io.File;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.net.InetAddress;import java.net.ServerSocket;import java.net.Socket;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[] ars) {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);}// Loop waiting for a requestwhile (!shutdown) {Socket socket = null;InputStream input = null;OutputStream output = null;try {socket = serverSocket.accept();input = socket.getInputStream();output = socket.getOutputStream();// create Request object and parseRequest request = new Request(input);request.parse();// create Response objectResponse response = new Response(output);response.setRequest(request);response.sendStaticResource();// Close the socketksocket.close();// check if the previous URI is a shutdown commandshutdown = request.getUri().equals(SHUTDOWN_COMMAND);} catch (Exception e) {e.printStackTrace();continue;}}}}package ex01.xiejiaohui;import java.io.IOException;import java.io.InputStream;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;}}package ex01.xiejiaohui;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.OutputStream;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 {// file not foundString 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) {// thrown if cannot instantiate a File objecte.printStackTrace();System.out.println(e.toString());} finally {if (fis != null) {fis.close();}}}}