//httpServer.java 
import java.net.*;
import java.io.*;
import java.util.*;
import java.lang.*;
public class httpServer{
	public static void main(String args[]) {
		int port;
		ServerSocket server_socket;
		//讀取服務(wù)器端口號(hào)
		try {
			port = Integer.parseInt(args[0]);
		}
		catch (Exception e) {
			port = 8080;
		}
		
		try {
			//監(jiān)聽服務(wù)器端口，等待連接請(qǐng)求
			server_socket = new ServerSocket(port);
			System.out.println("httpServer running on port " +
				server_socket.getLocalPort());
			//顯示啟動(dòng)信息
			while(true) {
				Socket socket = server_socket.accept();
				System.out.println("New connection accepted " +
					socket.getInetAddress() +
					":" + socket.getPort());
				//創(chuàng)建分線程
				try {
					httpRequestHandler request = new httpRequestHandler(socket);
					Thread thread = new Thread(request);
					//啟動(dòng)線程
					thread.start();
				}
				catch(Exception e) {
					System.out.println(e);
				}
			}
		}
		catch (IOException e) {
			System.out.println(e);
		}
	}
}

class httpRequestHandler implements Runnable {
	final static String CRLF = "\r\n";
	Socket socket;
	InputStream input;
	OutputStream output;
	BufferedReader br;
	// 構(gòu)造方法
	public httpRequestHandler(Socket socket) throws Exception{
		this.socket = socket;
		this.input = socket.getInputStream();
		this.output = socket.getOutputStream();
		this.br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
	}
	// 實(shí)現(xiàn)Runnable 接口的run()方法
	public void run()
	{
		try {
			processRequest();
		}
		catch(Exception e) {
			System.out.println(e);
		}
	}
	private void processRequest() throws Exception 
	{
		while(true) {
			//讀取并顯示W(wǎng)eb 瀏覽器提交的請(qǐng)求信息
			String headerLine = br.readLine();
			System.out.println("The client request is "+headerLine);
			if(headerLine.equals(CRLF) || headerLine.equals("")) 
				break;
			StringTokenizer s = new StringTokenizer(headerLine);
			String temp = s.nextToken();
			if(temp.equals("GET")) {
				String fileName = s.nextToken();
				fileName = "." + fileName ;
				// 打開所請(qǐng)求的文件
				FileInputStream fis = null ;
				boolean fileExists = true ;
				try{
					fis = new FileInputStream( fileName ) ;
				}
				catch ( FileNotFoundException e ){
					fileExists = false ;
				}
				// 完成回應(yīng)消息
				String serverLine = "Server: a simple java httpServer";
				String statusLine = null;
				String contentTypeLine = null;
				String entityBody = null;
				String contentLengthLine = "error";
				if ( fileExists ){
					statusLine = "HTTP/1.0 200 OK" + CRLF ;
					contentTypeLine = "Content-type: " +
						contentType( fileName ) + CRLF ;
					contentLengthLine = "Content-Length: "
						+ (new Integer(fis.available())).toString()
						+ CRLF;
				}
				else
				{
					statusLine = "HTTP/1.0 404 Not Found" + CRLF ;
					contentTypeLine = "text/html" ;
					entityBody = "＜HTML＞" +
						"＜HEAD＞＜TITLE＞404 Not Found＜/TITLE＞＜/HEAD＞" +
						"＜BODY＞404 Not Found"
						+"＜br＞usage:http://yourHostName:port/"
						+"fileName.html＜/BODY＞＜/HTML＞" ;
				}
				// 發(fā)送到服務(wù)器信息
				output.write(statusLine.getBytes());
				output.write(serverLine.getBytes());
				output.write(contentTypeLine.getBytes());
				output.write(contentLengthLine.getBytes());
				output.write(CRLF.getBytes());
				// 發(fā)送信息內(nèi)容
				if (fileExists){
					sendBytes(fis, output) ;
					fis.close();
				}
				else{
					output.write(entityBody.getBytes());
				}
			}
		}
		//關(guān)閉套接字和流
		try {
			output.close();
			br.close();
			socket.close();
		}
		catch(Exception e) {}
	}
	private static void sendBytes(FileInputStream fis, OutputStream os)
	throws Exception{
		// 創(chuàng)建一個(gè) 1K buffer
		byte[] buffer = new byte[1024] ;
		int bytes = 0 ;
		// 將文件輸出到套接字輸出流中
		while ((bytes = fis.read(buffer)) != -1 ){
			os.write(buffer, 0, bytes);
		}
	}
	private static String contentType(String fileName){
		if (fileName.endsWith(".htm") || fileName.endsWith(".html"))
		{
			return "text/html";
		}		
		return "fileName";
	}
}