打造自己的web容器（2）

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Web Socket 应用服务器浏览器 HTML

---- 一个简单的web容器

上一篇对socket作了一下简单介绍，这一篇对其进行扩展，建立一个能够读取静态资源的web容器雏形。
由三个类完成：
Request：包装浏览器的请求
Response：包装服务器端的响应
HttpServer：HTTP服务器(接受请求，发送响应)

/**
 * 包装浏览器的请求
 * @author chenwq
 */
public class Request {

	private InputStream input;

	private String uri;

	public Request(InputStream input) {

		this.input = input;
	}

	public void parse() {

		// Read a set of characters from the socket
		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]);
		}
		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;
	}
}

/**
 * 包装服务器端的响应
 * @author chenwq
 */
public class Response {
 
	private static final int BUFFER_SIZE = 1024;

	private Request request;

	private 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 {
			//根据 parent 路径名字符串和 child 路径名字符串创建一个新 File 实例
			//child 路径名字符串用于表示目录或文件
			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 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 (Exception e) {
			// thrown if cannot instantiate a File object
			System.out.println(e.toString());
		}
		finally {
			if (fis != null)
				fis.close();
		}
	}
}

/**
 * HTTP服务器(接受请求，发送响应)
 * @author chenwq
 */
public class HttpServer {

	/* WEB应用的根目录 */
	public static final String WEB_ROOT = System.getProperty("user.dir") + File.separator + "WebContent";

	// shutdown command
	private static final String SHUTDOWN_COMMAND = "/SHUTDOWN";

	// the shutdown command received
	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);
		}
		// Loop waiting for a request
		while (!shutdown) {
			Socket socket = null;
			InputStream input = null;
			OutputStream output = null;
			try {
				socket = serverSocket.accept();
				input = socket.getInputStream();
				output = socket.getOutputStream();
				// create Request object and parse
				Request request = new Request(input);
				request.parse();
				// create Response object
				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;
			}
		}
	}
}

测试页面：index.html，该页面位于 ${user.dir}/WebContent/ 下

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
		<title>Insert title here</title>
	</head>
	<body>
		<h1> Hello! MyWebContainer </h1>
	</body>
</html>

运行HttpServer，启动容器，在浏览器中键入：http://localhost:8080/index.html，得到如下反馈：