tomcat学习一（简单web服务器示例）

Request.java

package com.chen;

import java.io.IOException;
import java.io.InputStream;

public class Request {
	private InputStream input ;
	private String uri;
	
	public Request(){}
	public Request(InputStream input){
		this.input = input;
	}
	
	public void parse(){
		byte by[] = new byte[2048];
		int len = 0 ;
		StringBuilder sb = new StringBuilder();
		try {
			//while(len!=-1){
			len =input.read(by);
			System.out.println("len="+len);
			if(len>0){
				sb.append(new String(by,0,len));
			}
			//}
		} catch (IOException e) {
			e.printStackTrace();
		}
		this.uri = parseUri(sb.toString());
	}
	
	private String parseUri(String str) {
		int index1 , index2 ;
		index1 = str.indexOf(' ');
		if(index1!=-1){
			index2 = str.indexOf(' ',index1+1);
			if(index2>index1)
				return str.substring(index1+1,index2);
		}
		return null;
	}
	public String getUri() {
		return uri;
	}
	public void setUri(String uri) {
		this.uri = uri;
	}
	
}

Response.java

package com.chen;

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;
	private OutputStream output;
	private Request request ;
	
	public Response(){}
	
	public Response(OutputStream output){
		this.output = output;
	}

	public Request getRequest() {
		return request;
	}

	public void setRequest(Request request) {
		this.request = request;
	}
	
	public void sendStaticResource() throws IOException{
		byte[] bytes = new byte[BUFFER_SIZE];
		FileInputStream fis = null;
		try{
			System.out.println("uri:"+request.getUri());
			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){
			e.printStackTrace();
		}finally{
			if(fis!=null){
				fis.close();
			}
		}
		
	}
	
}

HttpServer.java

package com.chen;

import java.io.File;
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";
	public static final String SHUTDOWN_COMMAND="/SHUTDOWN";
	
	public static void main(String[] args) {
		HttpServer server = new HttpServer();
		server.await();
	}
	private boolean shutdown = false;
	
	public void await(){
		ServerSocket serverSocket = null;
		int port = 8080;
		try{
			serverSocket = new ServerSocket(port, 1, InetAddress.getByName("127.0.0.1"));
		}catch(Exception e){
			e.printStackTrace();
			System.exit(1);
		}
		
		while(!shutdown){
			Socket socket = null;
			InputStream input = null;
			OutputStream output = null;
			try{
				socket = serverSocket.accept();
				input = socket.getInputStream();
				output = socket.getOutputStream();
				
				Request request = new Request(input);
				request.parse();
				
				Response response = new Response(output);
				response.setRequest(request);
				response.sendStaticResource();
				
				socket.close();
				
			}catch(Exception e){
				e.printStackTrace();
				System.exit(1);
			}
			
			
		}
		
	}
}