找到本好书,《How Tomecat Work》。嘻嘻,按里面的章节学习中。
今天仿写了一个非常简单的 HttpServer,可是在第二次访问时就出错了。郁闷啊,还不知道原因,先记录一下,下次再研究出错的原因。
package server; import java.io.*; import java.net.*; /** * HttpServer to handler HTTP request. * * @author Cream * @since 2011-06-06 */ public class HttpServer { public static final String WEB_ROOT = System.getProperty("user.dir") + File.separator; private final String SHUTDOWN_COMMAND = "/SHUTDOWN"; private int port = 8080; private boolean shutdown = false; public static void main(String[] args) { HttpServer server = new HttpServer(); server.await(); } public void await() { ServerSocket server = null; try { server = new ServerSocket(port, 1, InetAddress.getByName("127.0.0.1")); } catch (IOException e) { e.printStackTrace(); System.exit(1); } // Loop waiting for a request while (!shutdown) { Socket socket = null; InputStream input = null; OutputStream output = null; try { socket = server.accept(); input = socket.getInputStream(); output = socket.getOutputStream(); Request request = new Request(input); request.parse(); Response response = new Response(output); response.setRequest(request); response.sendStaticResource(); // Close the socket socket.close(); // Check if the previous URI is a shutdown command shutdown = request.getUri().equals(SHUTDOWN_COMMAND); } catch (Exception e) { e.printStackTrace(); continue; } } } }
package server; import java.io.*; import java.net.*; public class Request { private final InputStream input; private String uri; public Request(InputStream input) { this.input = input; } public String getUri() { return this.uri; } public void parse() throws IOException { StringBuffer request = new StringBuffer(); InputStreamReader isr = new InputStreamReader(input); BufferedReader reader = new BufferedReader(isr); try { // Now we only read the first line to get URI. String header = null; if (reader.ready()) { // 这里出错了,貌似不是总是 ready 状态的。 header = reader.readLine(); this.uri = parseUri(header); } // Output the other HTTP header information System.out.println(header); while (reader.ready()) { System.out.println(reader.readLine()); } } catch (IOException e) { e.printStackTrace(); } } public void close() { try { if (input != null) { input.close(); } } catch (IOException e) { e.printStackTrace(); } } private String parseUri(String header) { int index1, index2; index1 = header.indexOf(' '); if (index1 != -1) { index2 = header.indexOf(' ', index1 + 1); if (index2 > index1) { return header.substring(index1 + 1, index2); } } return null; } }
package server; import java.io.*; import java.net.*; public class Response { private int BUFFER_SIZE = 8192; private final OutputStream output; private Request request; 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]; String uri = request.getUri(); System.out.println("HttpServer.WEB_ROOT:" + HttpServer.WEB_ROOT); File file = new File(HttpServer.WEB_ROOT, uri); FileInputStream fis = null; try { if (file.exists()) { // Output file 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 found 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 (IOException e) { e.printStackTrace(); } } }