My First Web Server

My First Web Server

HttpServer.java

package com.xiejiaohui.ch1;

import java.io.File;
import java.io.IOException;
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";
    private static final String SHUTDOWN_COMMAND = "/SHUTDOWN";

    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);
        }
        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();
                
                shutdown = request.getUri().equals(SHUTDOWN_COMMAND);
            } catch (Exception e) {
                e.printStackTrace();
                continue;
            }
        }
        
    }

}

Request.java

package com.xiejiaohui.ch1;

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

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;
    }

}

Response.java

package com.xiejiaohui.ch1;

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 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 {
            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();
            System.out.println(e.toString());
        } finally {
            if (fis != null) {
                fis.close();
            }
        }
    }
    

}