package cn.how2j.diytomcat.util;

public class Constant {
    public final static String response_head_202 =
            "HTTP/1.1 200 OK\r\n" +
            "Content-Type: {}\r\n\r\n";
}

package cn.how2j.diytomcat.http;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;

public class Response {

    private StringWriter stringWriter;
    private PrintWriter writer;
    private String contentType;
    public Response(){
        this.stringWriter = new StringWriter();
        this.writer = new PrintWriter(stringWriter);
        this.contentType = "text/html";
    }

    public String getContentType() {
        return contentType;
    }

    public PrintWriter getWriter() {
        return writer;
    }

    public byte[] getBody() throws UnsupportedEncodingException {
        String content = stringWriter.toString();
        byte[] body = content.getBytes("utf-8");
        return body;
    }

}

package cn.how2j.diytomcat;

import cn.how2j.diytomcat.http.Request;
import cn.how2j.diytomcat.http.Response;
import cn.how2j.diytomcat.util.Constant;
import cn.hutool.core.util.ArrayUtil;
import cn.hutool.core.util.NetUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.core.util.ZipUtil;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Bootstrap {

    public static void main(String[] args) {

        try {
            int port = 18080;

            if(!NetUtil.isUsableLocalPort(port)) {
                System.out.println(port +" 端口已经被占用了，排查并关闭本端口的办法请用：\r\nhttps://how2j.cn/k/tomcat/tomcat-portfix/545.html");
                return;
            }
            ServerSocket ss = new ServerSocket(port);

            while(true) {
                Socket s =  ss.accept();
                Request request = new Request(s);
                System.out.println("浏览器的输入信息： \r\n" + request.getRequestString());
                System.out.println("uri:" + request.getUri());

                Response response = new Response();
                String html = "Hello DIY Tomcat from how2j.cn";
                response.getWriter().println(html);

                handle200(s, response);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    private static void handle200(Socket s, Response response) throws IOException {
        String contentType = response.getContentType();
        String headText = Constant.response_head_202;
        headText = StrUtil.format(headText, contentType);
        byte[] head = headText.getBytes();

        byte[] body = response.getBody();

        byte[] responseBytes = new byte[head.length + body.length];
        ArrayUtil.copy(head, 0, responseBytes, 0, head.length);
        ArrayUtil.copy(body, 0, responseBytes, head.length, body.length);

        OutputStream os = s.getOutputStream();
        os.write(responseBytes);
        s.close();
    }
}