《深入剖析Tomcat》阅读(一)

package com.simpleHttpServer;

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";

	// 关闭HttpServer命令
	private static final String SHUTDOWN_COMMAND = "/SHUTDOWN";

	// 是否收到关闭HttpServer命令
	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);
		}

		// 循环等待Http请求
		while (!shutdown)
		{
			Socket socket = null;
			InputStream input = null;
			OutputStream output = null;
			try
			{
				socket = serverSocket.accept();
				input = socket.getInputStream();
				output = socket.getOutputStream();

				// 创建一个Request对象并解析
				Request request = new Request(input);
				request.parse();

				// 创建一个Response对象
				Response response = new Response(output);
				response.setRequest(request);
				response.sendStaticResource();

				// 关闭socket
				socket.close();

				// 检查是否是关闭命令
				shutdown = request.getUri().equals(SHUTDOWN_COMMAND);
			} catch (Exception e)
			{
				e.printStackTrace();
				continue;
			}
		}
	}
}

package com.simpleHttpServer;

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;
	}

}

package com.simpleHttpServer;

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();
		}
	}
}

try
   {
	serverSocket = new ServerSocket(port, 1, InetAddress.getByName("127.0.0.1"));
   } catch (IOException e)
   {
	 e.printStackTrace();
	 System.exit(1);
   }

public ServerSocket(int port, int backlog, InetAddress bindAddr) throws IOException {
        setImpl();
        if (port < 0 || port > 0xFFFF)
            throw new IllegalArgumentException(
                       "Port value out of range: " + port);
        if (backlog < 1)
          backlog = 50;
        try {
            bind(new InetSocketAddress(bindAddr, port), backlog);
        } catch(SecurityException e) {
            close();
            throw e;
        } catch(IOException e) {
            close();
            throw e;
        }
    }