SimpleHttpServer

SimpleHttpServer.java

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;

public class SimpleHttpServer {

    private static String requestPath;

    private static Map<String, String> CONTENT_TYPES = new HashMap<String, String>();

    static {
        CONTENT_TYPES.put("html", "text/html");
        CONTENT_TYPES.put("htm", "text/html");
        CONTENT_TYPES.put("css", "text/css");
        CONTENT_TYPES.put("js", "text/javascript");
        CONTENT_TYPES.put("jpg", "image/jpeg");
        CONTENT_TYPES.put("jpeg", "image/jpeg");
        CONTENT_TYPES.put("png", "image/png");
        CONTENT_TYPES.put("gif", "image/gif");
        CONTENT_TYPES.put("pdf", "application/pdf");
        CONTENT_TYPES.put("txt", "text/plain");
        CONTENT_TYPES.put("xml", "text/xml");
        CONTENT_TYPES.put("zip", "application/zip");
        CONTENT_TYPES.put("exe", "application/octet-stream");
    }

    public static void main(String[] args) throws IOException {
        String documentRoot = args[0];
        int port = Integer.parseInt(args[1]);

        ServerSocket server = new ServerSocket(port);

        while (true) {
            Socket client = server.accept();

            // HTTPリクエストを出力
            outputRequest(client);

            // HTTPレスポンスを出力
            outputResponse(client, documentRoot);
        }
    }

    private static void outputRequest(Socket client) throws IOException {
        System.out.println("------------------------------------------");

        BufferedReader br = new BufferedReader(new InputStreamReader(client.getInputStream()));

        // 1行目からリクエストパスを取得しておく（/でアクセスされた場合はindex.htmlを表示）
        String inline = br.readLine();
        requestPath = inline.split(" ")[1];
        if (requestPath.endsWith("/")) {
            requestPath += "index.html";
        }

        while (br.ready() && inline != null) {
            System.out.println(inline);
            inline = br.readLine();
        }

        System.out.println("------------------------------------------");
    }

    private static void outputResponse(Socket client, String documentRoot) throws IOException {
        PrintStream ps = new PrintStream(client.getOutputStream());

        String responseFile = documentRoot + requestPath;
        File file = new File(responseFile);

        FileInputStream fis = null;
        try {
            fis = new FileInputStream(file);

            // ヘッダー出力
            int bodyLength = (int) file.length();
            ps.println("HTTP/1.1 200 OK");
            ps.println("Content-Length: " + bodyLength);
            ps.println("Content-Type: " + getContentType(file));
            ps.println("");

            // ボディ出力
            byte buf[] = new byte[bodyLength];

            fis.read(buf);
            ps.write(buf, 0, bodyLength);
            ps.flush();
        } catch (FileNotFoundException e) {
            // ヘッダー出力
            ps.println("HTTP/1.1 404 Not Found");
            ps.println("");
            ps.println("<h1>指定されたファイルは存在しません。</h1>");
        } finally {
            if (fis != null) {
                fis.close();
            }
        }

        ps.close();
    }

    private static String getContentType(File file) {
        String extension = getExtension(file);

        String contentType = CONTENT_TYPES.get(extension);

        if (contentType == null) {
            return "text/html";
        } else {
            return contentType;
        }
    }

    private static String getExtension(File file) {
        String path = file.getPath();
        int lastDotPosition = path.lastIndexOf(".");

        String extension = null;
        if (lastDotPosition == -1) {
            extension = "";
        } else {
            extension = path.substring(lastDotPosition + 1).toLowerCase();
        }

        return extension;
    }
}